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914World.com _ 914World Garage _ The alternator replacement thread
Posted by: Vacca Rabite Aug 12 2018, 07:07 PM
Waiting on the side of the road for a flatbed to take me home.
Engine ran great. Charging system not so much. Driving along. Lights started going dim. Car started bucking. Only 5 miles to home but it wasn’t going to make it, and no shoulders to pull over safe on the little farm roads. So I pulled into a spot I knew of and shut it down and parked it and now I wait.
McMark had said earlier he wasn’t sure about the charging system. But the alt light was not on and no issues before now.
So. What’s the alternator I need to buy?
Maybe a new VR as well?
I guess I should test the battery and make sure it’s okay too.
Zach
Posted by: FL 000 Aug 12 2018, 07:26 PM
That sucks, I know the feeling. Same thing happened to me Friday but with a broken CV joint. Good that you are close to home and hopefully an easy fix.
Posted by: ClayPerrine Aug 12 2018, 07:32 PM
Did you check the generator light bulb? The wrong one will cause the alternator to fail to charge.
Posted by: Vacca Rabite Aug 12 2018, 07:57 PM
Bruce Stone is the man and has an alternator for me. Hopefully that is the issue and not a crapped out relay board or faulty wiring.
Zach
Posted by: bobboinski Aug 12 2018, 07:58 PM
Did you check the generator light bulb? The wrong one will cause the alternator to fail to charge.
Seriously? The more I know about these cars the more I love them!
Posted by: ClayPerrine Aug 12 2018, 08:06 PM
Did you check the generator light bulb? The wrong one will cause the alternator to fail to charge.
Seriously? The more I know about these cars the more I love them!
Very serious. The generator light provides the circuit to the alternator field. If the alternator is not charging, the light comes on because of the voltage differental between the alternator and the rest of the electrical system. When the alternator is charging, both sides of the bulb are "hot" so the light goes off.
That's why you can't use an LED in the generator light socket.
Posted by: Mark Henry Aug 12 2018, 08:25 PM
The alternator idiot light was on when you turned the key before starting right?
The light excites the field, so no light before starting and the alternator won't work.
Your alternator light not coming on once the charging system failed tells me something was wrong with the idiot light wiring circuit. That will also need to be fixed.
The two idiot lights are very important, I won't start my engines without them working correctly first.
Posted by: Vacca Rabite Aug 12 2018, 08:30 PM
Yup. Red light was on when I turned the key and went off when the engine started.
The light never turned on while I was driving. Just noticed the lights started getting dim about 10 miles into a 20 mile drive.
After I turned the car off on the side of the road, the alt light did not light when I tried to start the car again when the tow truck showed up. But the battery was really drained by then.
Zach
Posted by: Unobtanium-inc Aug 12 2018, 08:31 PM
I hate the site of a pretty Porsche being dragged, this was my car at my dentist's office, the last place I wanted to spend any extra time.
Hopefully your car is something easy.
Attached image(s)
Posted by: Vacca Rabite Aug 12 2018, 08:39 PM
I probably would have made it home if I had not needed to use the headlights. But, I would not have noticed the problem were it not for the headlights dimming and assumed something was wrong with the EFI when the car eventually started bucking.
Zach
Posted by: Mark Henry Aug 12 2018, 08:43 PM
Yup. Red light was on when I turned the key and went off when the engine started.
The light never turned on while I was driving. Just noticed the lights started getting dim about 10 miles into a 20 mile drive.
After I turned the car off on the side of the road, the alt light did not light when I tried to start the car again when the tow truck showed up. But the battery was really drained by then.
Zach
That is odd, as a preventative I'd still go through your grounds and connections at the combo gauge. Also make sure your battery posts, battery and trans ground straps, etc., are all clean and have good continuity.
Bad battery and ground connections can make your electrical system do wierd shite.
Posted by: bobboinski Aug 12 2018, 08:50 PM
Yup. Red light was on when I turned the key and went off when the engine started.
The light never turned on while I was driving. Just noticed the lights started getting dim about 10 miles into a 20 mile drive.
After I turned the car off on the side of the road, the alt light did not light when I tried to start the car again when the tow truck showed up. But the battery was really drained by then.
Zach
That is odd, as a preventative I'd still go through your grounds and connections at the combo gauge. Also make sure your battery posts, battery and trans ground straps, etc., are all clean and have good continuity.
Bad battery and ground connections can make your electrical system do wierd shite.
I had a bad ground on my Tacoma and the headlights would turn themselves on (dimly) and the warning buzzer would sound at about half volume. This would happen randomly. Guy I worked with said to check the grounds and he was right. Negative clamp on the battery was severely corroded so I replaced it and all has been fine for over a year now. Learned my lesson.
Posted by: r_towle Aug 12 2018, 09:03 PM
get an amp gauge.
Bummer, but you are so close man....glad you stuck with it.
rich
Posted by: Spoke Aug 12 2018, 09:04 PM
I wouldn't put in a new alternator until you know what is wrong with the charging system. Like Mark said, check all grounds and battery connections.
Charge the battery, remove the VR, short DF to D+ at the VR connector. This will put the alternator in maximum charge condition. Start the car and measure the battery voltage. If it is more than 15V, then the alternator is ok. Don't do this test too long as it applies maximum stress on the alternator and battery.
If you don't see 15V or so, the VR may be suspect.
I know the feeling of a Porsche riding on a flatbed. This ride from Pittsburgh to Allentown a couple of weeks ago cost me a cool $1000.
Posted by: Dave_Darling Aug 12 2018, 10:46 PM
I had a VR that came unplugged while I was driving. No warning light, and no charging either. The light did stay off after I shut the engine off and turned the key back on again, though.
--DD
Posted by: bdstone914 Aug 12 2018, 10:50 PM
Bruce Stone is the man and has an alternator for me. Hopefully that is the issue and not a crapped out relay board or faulty wiring.
Zach
I also have rebuild tested relay boards should that be the problem. Done by 914Sixer, Mark Heard.
Posted by: Amphicar770 Aug 13 2018, 06:09 AM
I wouldn't put in a new alternator until you know what is wrong with the charging system. Like Mark said, check all grounds and battery connections.
Charge the battery, remove the VR, short DF to D+ at the VR connector. This will put the alternator in maximum charge condition. Start the car and measure the battery voltage. If it is more than 15V, then the alternator is ok. Don't do this test too long as it applies maximum stress on the alternator and battery.
If you don't see 15V or so, the VR may be suspect.
I know the feeling of a Porsche riding on a flatbed. This ride from Pittsburgh to Allentown a couple of weeks ago cost me a cool $1000.
Ouch! If you drive older cars, AAA Platinum is a must have. My Jaguar got a free flatbed ride from Virginia to North of Philly about a year ago.
Posted by: Unobtanium-inc Aug 13 2018, 06:47 AM
[/quote]
Ouch! If you drive older cars, AAA Platinum is a must have. My Jaguar got a free flatbed ride from Virginia to North of Philly about a year ago.
[/quote]
Yes, AAA is a must if you're driving an old car. Plus you save at hotels and stuff.
Posted by: dr914@autoatlanta.com Aug 13 2018, 06:58 AM
yup you ran out of juice, would check the belt tightness and then the voltage regulator, a new Bosch alternator is the final solution if the other two fail to 'rectify"
Waiting on the side of the road for a flatbed to take me home.
Engine ran great. Charging system not so much. Driving along. Lights started going dim. Car started bucking. Only 5 miles to home but it wasn’t going to make it, and no shoulders to pull over safe on the little farm roads. So I pulled into a spot I knew of and shut it down and parked it and now I wait.
McMark had said earlier he wasn’t sure about the charging system. But the alt light was not on and no issues before now.
So. What’s the alternator I need to buy?
Maybe a new VR as well?
I guess I should test the battery and make sure it’s okay too.
Zach
Posted by: bdstone914 Aug 13 2018, 08:10 AM
I wouldn't put in a new alternator until you know what is wrong with the charging system. Like Mark said, check all grounds and battery connections.
Charge the battery, remove the VR, short DF to D+ at the VR connector. This will put the alternator in maximum charge condition. Start the car and measure the battery voltage. If it is more than 15V, then the alternator is ok. Don't do this test too long as it applies maximum stress on the alternator and battery.
If you don't see 15V or so, the VR may be suspect.
I know the feeling of a Porsche riding on a flatbed. This ride from Pittsburgh to Allentown a couple of weeks ago cost me a cool $1000.
AAA Extended plan cost about $160 a years and well worth it. You get two tows per year up to 200 miles each . Did that after a 25 mile tow cost $125 with towing "insurance". But I see that is is closer to 300 miles from Pittsburgh to Allentown.
Posted by: Vacca Rabite Aug 13 2018, 08:19 AM
I have AAA gold so my tow was covered. As I gain confidence with the car and drive it further I’ll maybe up my service.
Did a test this morning with a spare VR I had.
Battery charged overnight.
With a newer VR (the one on the car last night when it failed) the Alternator light did not turn on when I put the key in.
With the old rusty “spare” the light lit up on key in, but did not turn off when the car started, even after I revved the engine.
Oh. And WHY AM I NOT WORKING ON A MONDAY you ask? Electrical storm last night took out power to the upper floors of my house (without tripping the breaker) at about 2:30 am; so now I’m waiting for the electrician to see what the damage is. At least 1/2 my House has power. :-/
Posted by: mepstein Aug 13 2018, 08:34 AM
I hope the house is ok. We had flooding in SE PA. Couldn’t pull out of the driveway the water was so deep this morning.
Posted by: Vacca Rabite Aug 13 2018, 09:09 AM
Just did Spokes test of shorting DF and D+.
Battery went from 12.12 volts engine off to 11.87 volts engine on at idle.
If I understand correctly even at idle I should expect to see greater then 12 volts with the VR shorted to Max Effort state. I’m guess the alternator is just dead. 
I also made sure the belt was tight, and it was good and tight.
Going through grounds and don’t see anything too off kilter, though I have only looked at engine bay grounds as yet.
This alternator, by the way, only had about 300 miles on it. It failed really quick.
While I’m thinking about t, is there a way to bench test the voltage regulators?
Zach
Posted by: Vacca Rabite Aug 13 2018, 09:12 AM
I hope the house is ok. We had flooding in SE PA. Couldn’t pull out of the driveway the water was so deep this morning.
I can’t find evidence of lightning having hit the house, but the crash last night was right on top of us.
I turned off the breaker for the suspected circuits so the house didn’t burn down and tried to go back to sleep.
When it rains it pours I suppose. Lol.
Zach.
Posted by: 1adam12 Aug 13 2018, 11:26 AM
I have AAA gold so my tow was covered. As I gain confidence with the car and drive it further I’ll maybe up my service.
Did a test this morning with a spare VR I had.
Battery charged overnight.
With a newer VR (the one on the car last night when it failed) the Alternator light did not turn on when I put the key in.
With the old rusty “spare” the light lit up on key in, but did not turn off when the car started, even after I revved the engine.
Oh. And WHY AM I NOT WORKING ON A MONDAY you ask? Electrical storm last night took out power to the upper floors of my house (without tripping the breaker) at about 2:30 am; so now I’m waiting for the electrician to see what the damage is. At least 1/2 my House has power. :-/
I don't know man... sounds like the beginning of 'War of the Worlds'. If Tom Cruise runs by your house, you should run too! Just say'n lol
Posted by: Vacca Rabite Aug 13 2018, 11:39 AM
Electrician for the house will be here in a few minutes, but I've searched all the grounds from the cockpit back. Battery to body is pristine. Trans to body has no corrosion. Every place that grounds in the engine bay was tip-top. I need to look in the cockpit yet, but I suspect things will be good there too. The car is kept indoors and I don't have that many miles on the body since the restoration ended back in 2009/2010. If the ground that are exposed to the elements are good, I have to think the cockpit grounds will be good too.
Zach
Posted by: ClayPerrine Aug 13 2018, 12:16 PM
Just did Spokes test of shorting DF and D+.
Battery went from 12.12 volts engine off to 11.87 volts engine on at idle.
If I understand correctly even at idle I should expect to see greater then 12 volts with the VR shorted to Max Effort state. I’m guess the alternator is just dead.
I also made sure the belt was tight, and it was good and tight.
Going through grounds and don’t see anything too off kilter, though I have only looked at engine bay grounds as yet.
This alternator, by the way, only had about 300 miles on it. It failed really quick.
While I’m thinking about t, is there a way to bench test the voltage regulators?
Zach
A Bosch alternator is a B circuit alternator. That means that applying 12v to the field (DF) terminal on the alternator will make it provide maximum output, somewhere in the neighborhood of 15 to 18 volts. You should also hear the whine come from the alternator and an RPM drop on the motor.
Zach.. check and make sure the relay board is not the culprit. Pull the 3pin alternator plug off the relay board, and with the car running, apply 12v from the battery positive post to the DF terminal. If you don't get 15 to 18 volts and a whine, I would replace the alternator and the wiring harness to it. There is a group sale on the harnesses going on right now in another thread.
Buy a new Bosch alternator. A lot of the "rebuilt" alternators out there are just cleaned and maybe replace the brushes.
Posted by: 914_teener Aug 13 2018, 12:27 PM
So was a battery charger plugged in and hooked up to your car when the lightning struck?
Posted by: Vacca Rabite Aug 13 2018, 12:31 PM
So was a battery charger plugged in and hooked up to your car when the lightning struck?
Yes, but the garage seems to have escaped unharmed.
Electrician is here now, and power is restored to the entire house. A bathroom GFI outlet died though and requires replacement.
Zach
Posted by: Vacca Rabite Aug 13 2018, 12:37 PM
A Bosch alternator is a B circuit alternator. That means that applying 12v to the field (DF) terminal on the alternator will make it provide maximum output, somewhere in the neighborhood of 15 to 18 volts. You should also hear the whine come from the alternator and an RPM drop on the motor.
Zach.. check and make sure the relay board is not the culprit. Pull the 3pin alternator plug off the relay board, and with the car running, apply 12v from the battery positive post to the DF terminal. If you don't get 15 to 18 volts and a whine, I would replace the alternator and the wiring harness to it. There is a group sale on the harnesses going on right now in another thread.
Buy a new Bosch alternator. A lot of the "rebuilt" alternators out there are just cleaned and maybe replace the brushes.
I'll check it, though it will be after the electrician for the house leaves.
I bought the alternator and VR Bruce had. Its rebuilt but by a local guy that he trusts to do it right. If Bruce trusts it, so do I.
Zach
Posted by: ClayPerrine Aug 13 2018, 12:45 PM
A Bosch alternator is a B circuit alternator. That means that applying 12v to the field (DF) terminal on the alternator will make it provide maximum output, somewhere in the neighborhood of 15 to 18 volts. You should also hear the whine come from the alternator and an RPM drop on the motor.
Zach.. check and make sure the relay board is not the culprit. Pull the 3pin alternator plug off the relay board, and with the car running, apply 12v from the battery positive post to the DF terminal. If you don't get 15 to 18 volts and a whine, I would replace the alternator and the wiring harness to it. There is a group sale on the harnesses going on right now in another thread.
Buy a new Bosch alternator. A lot of the "rebuilt" alternators out there are just cleaned and maybe replace the brushes.
I'll check it, though it will be after the electrician for the house leaves.
I bought the alternator and VR Bruce had. Its rebuilt but by a local guy that he trusts to do it right. If Bruce trusts it, so do I.
Zach
If you were close to me, I would give you one of the 8 known good alternators I have sitting on a shelf in my attic. They all have wiring harnesses and the metal air deflectors installed.
Posted by: Vacca Rabite Aug 14 2018, 07:32 AM
So, new alt, VR and harness are all on order.
Hopefully this weekend I'll be able to start putting on new parts.
I guess to fill the time I could start working on the front of the car. I have a headlight bushing kit my car desperately needs, as well as putting the surrounds back on.
Ass of the car is up in the air, so I could go and pull the tin and the old alternator too. Just get everything ready to go.
And I suppose I could start hooking up the cabin gauges again. You know, so I'd know next time when my charging system is about to take a dump on me.
Zach
Posted by: 90quattrocoupe Aug 14 2018, 11:21 AM
Nothing to do with the car, but if your GFI plug going bad takes out the whole circuit, then it is wired in series.
The cheap way to wire a house is to wire it up in series. This takes less wiring and less time.
The proper way is to wire a circuit in parallel. A lot of electricians don't want to take the time to put pig tails on the plugs. They just wire up the plugs so the circuit goes through the plug. If a plug goes out, it takes out the whole circuit.
Greg W.
Posted by: 914_teener Aug 14 2018, 12:34 PM
Check the ignition switch.
Posted by: Vacca Rabite Aug 18 2018, 07:59 PM
Tonight I put the new alternator, harness and VR in.
The red GEN light shone bright red at key in and turned off as soon as the engine started.
So that’s done, and initial results are promising.
At idle (about 1000 rpm) the battery was showing 12.89 volts (measured at the battery using a multi-meter) and RISING. I did not test amps. Is that about what I should expect to see from the alternator measuring voltage at the battery while at idle?
Haynes is saying 14 volts (mean) at 2200-6000 rpm, but I don’t know where they were measuring that. I guess I should test again tomorrow at a higher RPM. THATS what I get for looking at Haynes after I do the test.
Zach
Posted by: Spoke Aug 18 2018, 08:08 PM
12.89V at idle after the engine is warmed up or right after the engine started?
What is the voltage at higher revs?
Above 12.6V is good since the system is charging the battery. The voltage should be 13.5-14.0 at higher revs.
Posted by: Vacca Rabite Aug 18 2018, 08:10 PM
12.89V at idle after the engine is warmed up or right after the engine started?
What is the voltage at higher revs?
Above 12.6V is good since the system is charging the battery. The voltage should be 13.5-14.0 at higher revs.
Right after the engine started.
I only ran the car long enough to start it and measure voltage. Car was on maybe 2 minutes tops.
Zach
Posted by: Spoke Aug 18 2018, 08:48 PM
It sounds ok so far. How many times did you rev the engine? That's when the alternator and VR will reach peak efficiency. As soon as you start the engine the battery has been weaken by the load of the start and the alternator+VR usually are running at low RPM during the start. A measurement at 2-3K after a minute or 2 warm up will let you know how the alternator+VR are working.
12.8-13.1 is good just after the start with low revs. Should increase to 13.25-14V when revving the engine.
Posted by: Vacca Rabite Aug 20 2018, 04:07 PM
System still isn’t charging right.
I drove the car to the gym, and then around. Maybe 7 miles. Pulled into the house and got the mutimeter out.
At idle I was showing 12.12 volts across the battery terminals.
Revving the car to 3k and I was showing 12.06 across the terminals. I should be seeing more at rev.
Grounds are good
Alternator, voltage regulator, and voltage harness are all replaced. Gen light is acting like it should.
I shorted D+ to DF and the engine loaded up and I saw 15 volts bear idle.
So what’s next?
Relay board?
New VR still suspect?
Zach
Posted by: MarkV Aug 20 2018, 05:04 PM
A fully charged car battery should be 12.6 volts so I would say that if you have less than that at idle you are running off the battery.
A normal working charging system should read 13.5-14 at idle.
Do you have a known good VR you can try?
Doesn't make sense that the board is bad if you can jump the VR leads and get it to charge.
Posted by: 904svo Aug 20 2018, 05:05 PM
Made sure you have the correct bulb (not a led ) in the gen lamp socket. Since
this bulb supply the voltage to make the generator work correctly a wrong bulb will
cause strange things to happen.
Posted by: Vacca Rabite Aug 20 2018, 06:16 PM
Made sure you have the correct bulb (not a led ) in the gen lamp socket. Since
this bulb supply the voltage to make the generator work correctly a wrong bulb will
cause strange things to happen.
I know about the GEN light bootstrap. That light is correct.
Doesn't make sense that the board is bad if you can jump the VR leads and get it to charge.
I need to find the other two voltage regulators I have and test them. I hope I did not toss them away Saturday/Sunday while doing the alternator replacement.
I know its working better. Before when I did the D+ to DF test there was no load on the engine or anything. Changing the alternator HELPED but I don't think it fixed everything. And I'm concerned there is an underlying issue that killed the alternator. It may well be the VR.
Zach
Posted by: Robnxious Aug 20 2018, 08:01 PM
I just got done running this issue down as well myself. While the Alt light would go out when I started the car and revved it, and it SEEMED like it was charging, it wasn't until I replaced my VR that I was able to get the alternator to start correctly charging the battery. I ended up getting a Hella replacement, which is a bit smaller, though it doesn't look like this
https://www.amazon.com/gp/product/B01LT7E5RQ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
Posted by: MarkV Aug 20 2018, 10:33 PM
Years ago when I thought my mechanical VR was going bad I replaced it with one similar to this:
https://www.ebay.com/itm/Auto-Tune-PT825-Voltage-Regulator/182685301557?fits=Make%3APorsche%7CModel%3A914&epid=14006105162&hash=item2a88e47b35:g:~DkAAOSwUrdZdz~6
It is solid state and the electronics are potted. There is a short pigtail and the VR mounts where the screw for the mechanical VR mounts. I think they make an ajustable one as well.
Posted by: MarkV Aug 20 2018, 10:36 PM
Adjustable:
https://www.ebay.com/itm/NEW-ALTERNATOR-ADJUSTABLE-EXTERNAL-VOLTAGE-REGULATOR-Fits-PORSCHE-911-914-MORE/291674432232?fits=Make%3APorsche%7CModel%3A914&hash=item43e926a2e8:g:PDIAAOSwFMZWrpTX:sc:USPSPriority!85749!US!-1
That one might be for a 6 cylinder?
Posted by: Vacca Rabite Aug 21 2018, 07:10 AM
I bought one of the solid state pig-tailed voltage regulators off Amazon. Costs a little more but will be at my door wednesday.
By sheer force of will, this will work. I don't want to buy a new relay board. I am worried though that I've now had 4 VRs for this car. I think they have all been the mechanical points type though, and I know mine was ancient. The one from McMark was newish, but may have been damaged by the failing alternator. I don't know what to say about the NOS mechanical one from Bruce.
And if this new one does not work, I've got to assume an issue with the relay board itself, and not the VRs fault at all.
Zach
Posted by: plas76targa Aug 21 2018, 08:29 AM
Zach, This issue was the first ‘problem’ i experienced with my 914 soon after buying it in 2005. After all the tests, try several VRs, I put a WTB in the adds and Gerald sent one au gratis. [i was for ever committed to 914 world]. Try a different relay board.
Posted by: Vacca Rabite Aug 22 2018, 04:44 PM
Well, the new solid state VR did nothing.
I am forced to admit the issue MUST be with the board.
Though it is probably folly, I am going to attempt to rehab the board. I have a feeling this board has been the death of 2 alternators and probably other gremlins that have plagued me and McMark and the others who have helped withthis car over the years.
When I took the board off there was already evidence of a previous "repair" where someone had taken the potting off around the VR plug and soldered something down. I'm going to clear all the potting and start from new.
Because I'm stubborn. And I want to drive my car maybe this weekend.
Its frustrating as the car seems to be charging at idle. I had a meter on the battery for about 15 minutes and the battery went from 12.25 volts at start to 12.54 volts after a few minutes.
But as SOON as the engine revved to about 3000rpm, the battery fell to 12.01 and bounced around on the meter.
If I can't find an issue on the board by Friday, I'll suck it up and put up a post for a new board.
@http://www.914world.com/bbs2/index.php?showuser=3031
Zach
Posted by: 904svo Aug 22 2018, 06:52 PM
With the engine running measure for voltage between the alternator body and the engine case if you measure any voltage you have a grounding problem with the alternator and the engine case with the bolts hold the alternator in place
Posted by: Spoke Aug 22 2018, 07:54 PM
While you have the relay board out, measure the resistance between the D+ to D+, DF to DF to Pin 2 of the cabin connector, and D- to D-.
You can see by the schematic below that the relay board doesn't do too much for the alternator except provide a place to mount the voltage regulator and provide a wire back to the dash for the GEN light.
You shouldn't be killing alternators that easily. Check all grounds and the transmission strap. When you had your engine out you didn't paint or powder coat the fan shroud? The alternator is grounded to the shroud and the only direct ground connection to the engine case are the 4 little studs attaching the shroud to the engine. The tin might also provide some grounding but it's really those little studs providing the most grounding.
Attached thumbnail(s)
Posted by: mepstein Aug 22 2018, 08:33 PM
Well, the new solid state VR did nothing.
I am forced to admit the issue MUST be with the board.
Though it is probably folly, I am going to attempt to rehab the board. I have a feeling this board has been the death of 2 alternators and probably other gremlins that have plagued me and McMark and the others who have helped withthis car over the years.
When I took the board off there was already evidence of a previous "repair" where someone had taken the potting off around the VR plug and soldered something down. I'm going to clear all the potting and start from new.
Because I'm stubborn. And I want to drive my car maybe this weekend.
Its frustrating as the car seems to be charging at idle. I had a meter on the battery for about 15 minutes and the battery went from 12.25 volts at start to 12.54 volts after a few minutes.
But as SOON as the engine revved to about 3000rpm, the battery fell to 12.01 and bounced around on the meter.
If I can't find an issue on the board by Friday, I'll suck it up and put up a post for a new board.
@http://www.914world.com/bbs2/index.php?showuser=3031
Zach
If you need another board, just pm me your address. I have a good one you can have $n/c. If I send tomorrow, you should receive Saturday.
Posted by: Vacca Rabite Aug 22 2018, 09:34 PM
While you have the relay board out, measure the resistance between the D+ to D+, DF to DF to Pin 2 of the cabin connector, and D- to D-.
You shouldn't be killing alternators that easily. Check all grounds and the transmission strap. When you had your engine out you didn't paint or powder coat the fan shroud? The alternator is grounded to the shroud and the only direct ground connection to the engine case are the 4 little studs attaching the shroud to the engine. The tin might also provide some grounding but it's really those little studs providing the most grounding.
I did in fact powder coat the shroud and tins. That could be it.
I’ll run a ground wire from the alternator bolt to the engine case.
My other grounds are all golden. Trans, battery, and wire harness all made solid connections. I did not know about how the alternator grounded though.
Zach
Posted by: Vacca Rabite Aug 22 2018, 09:36 PM
If you need another board, just pm me your address. I have a good one you can have $n/c. If I send tomorrow, you should receive Saturday.
Mark. Yes please! Pm sent.
Zach
Posted by: Spoke Aug 23 2018, 04:42 AM
I did in fact powder coat the shroud and tins. That could be it.
I’ll run a ground wire from the alternator bolt to the engine case.
My other grounds are all golden. Trans, battery, and wire harness all made solid connections. I did not know about how the alternator grounded though.
Zach
If you didn't scratch off the powder coating from around the shroud mounting studs, the alternator not being grounded is a possibility. A grounding wire from the alternator case to the engine case is a good idea. Before you do this measure the resistance from the alt case to engine case. It should be zero ohms. Use a heavy wire like the one going from the alt to the starter.
There was another 914 owner who had charging trouble and also realized the accelerator cable was getting hot. It turned out the alternator was grounding through the cable.
Posted by: Vacca Rabite Aug 27 2018, 05:04 PM
I got Epstien's package in the mail today. So that was a good excuse to fiddle with the car after work.
I tested continuity from the alternator to the engine block and to the body. Very strong continuity, about one ohm resistance from the alternator case to the body. From the transmission to the body was basically zero resistance (there was a very small number on the screen of my meter). So, gounding was not an issue.
I replaced the board with a new one from Mark and put everything back. I am using the new solid state VR.
Started the car, and was measuring 12.6 volts at the battery on the meter at warm idle. Unplugged the VR and it dropped to 12 volts on the battery, and the engine idle speed increased slightly. So the car IS charging at idle.
Bring the throttle up to 4K rpm, and voltage dropped to 12.05 volts. So back to its old tricks. With all my lights on (driving lights, head lights, flashers) and the engine at 4K rpm I was only making 11.3 volts at the battery.
Unplugged the VR again and shorted DF to D+ and was making 14 volts at idle and the engine idle lowered noticeably.
I had my laptop plugged in and talking to the ECU, and the ECU is seeing about .6 volts less then my meter is seeing across the battery terminals. The tuning software was occationaly flashing the red "charging" flag.
At this place, I have replaced:
Alternator
VR (several times)
relay board
Alternator harness
I have confirmed that all the engine compartment grounds are in good shape.
About the only thing I can think to do at this time is add a ground wire from the alt to the engine case, but I really doubt that's my issue at this point. :-/
The other option is a bigger alternator (70 amp maybe?).
Is it at all possible that my battery is the issue? I'm using a Odessey race battery.
Thinking out loud. Is it at all possible that the alternator I put in (that I got from @http://www.914world.com/bbs2/index.php?showuser=1319 ) was internally regulated? Would double regulation do what I am seeing? How would I tell?
@http://www.914world.com/bbs2/index.php?showuser=3031
@http://www.914world.com/bbs2/index.php?showuser=1143
Zach
Posted by: Vacca Rabite Aug 27 2018, 05:09 PM
EVERYTHING seems to be pointing to the voltage regulator. But I've tried three of them now, and they have all acted the same.
I double checked belt tension on the alternator and I can push it in about 1/2 inch, which IIRC was the right tension. I'm not hearing any belt squeal or squeaks at speed, just healthy engine sounds.
I guess I could look for an adjustable VR and turn up the output. I SHOULD NOT need that, but if it works....?
Edit: I just bought an adjustable VR. Hopefully I'll be able to dial in a little bit more output.
Zach
Posted by: MarkV Aug 27 2018, 07:57 PM
Well I am stumped.
Idle at 12.6 volts is barely charging a fully charged battery should have 12.6 volts with the engine off. At an idle is should be 13 or more. I would be tempted to start from scratch and clean all of the grounds and terminals. Clean the battery terminals to bare metal. I run a heavy negative cable directly to one of the engine to transmission bolts. It could be that something is working barely at an idle but falls off under any kind of load.
Posted by: 904svo Aug 27 2018, 09:40 PM
just a WAG try cleaning fuse #9 (both sides) this supply the voltage to excite the
alternator if its dirty it could stop it from charging.
Posted by: Spoke Aug 28 2018, 04:53 AM
If you're measuring one ohm between the alt case and engine block, this should be considered a very large resistance. If indeed you have 1 ohm resistance between alt case and engine block, this would account for strange behavior and not as much voltage applied to the battery.
Ohms law is V = I x R. With 1 ohm if there is 1 amp of charging current, there will be 1V drop in a system where the difference between 1-2V is huge.
You can test to see if you have a voltage drop from alt case to chassis by measuring at the VR from D- to chassis. See the schematic below where D- at the VR is connected to the alt case. Short D+ to DF; start the car and measure voltage from D- to chassis. There's a chassis stud right by the relay board. You should read zero volts or near there.
Attached thumbnail(s)
Posted by: McMark Aug 28 2018, 05:16 AM
I can't remember...
Is your alternator harness new?
Battery positive cable?
Battery?
You can also attach the VR directly to the alternator harness, bypassing the relay board, BUT you'll have to add a jumper wire to bootstrap the alt and make it charge.
Another aspect is that a dead/dying battery won't take a full charge, and that can look like charging issues.
Oh and I have the distinct impression your car has a curse on the electrical system.
Posted by: Vacca Rabite Aug 28 2018, 07:35 AM
I can't remember...
Is your alternator harness new?
Battery positive cable?
Battery?
You can also attach the VR directly to the alternator harness, bypassing the relay board, BUT you'll have to add a jumper wire to bootstrap the alt and make it charge.
Another aspect is that a dead/dying battery won't take a full charge, and that can look like charging issues.
Oh and I have the distinct impression your car has a curse on the electrical system.
New Alt. New Alternator harness. New VR.
Battery is the Odyssey race battery that came from your shop last year. No telling how old it is.
And my car decidedly has some sort of gremlins. I'm slowly eliminating them.
Zach
Posted by: jarodswordmaster Sep 5 2018, 05:56 AM
I can't remember...
Is your alternator harness new?
Battery positive cable?
Battery?
You can also attach the VR directly to the alternator harness, bypassing the relay board, BUT you'll have to add a jumper wire to bootstrap the alt and make it charge.
Another aspect is that a dead/dying battery won't take a full charge, and that can look like charging issues.
Oh and I have the distinct impression your car has a curse on the electrical system.
New Alt. New Alternator harness. New VR.
Battery is the Odyssey race battery that came from your shop last year. No telling how old it is.
And my car decidedly has some sort of gremlins. I'm slowly eliminating them.
Zach
Where have you gotten with this now? Did you find the culprit. I'm going through the same scenario and don't feel like spending what I don't need to spend for parts that are okay.
Posted by: VaccaRabite Sep 5 2018, 06:37 AM
I can't remember...
Is your alternator harness new?
Battery positive cable?
Battery?
You can also attach the VR directly to the alternator harness, bypassing the relay board, BUT you'll have to add a jumper wire to bootstrap the alt and make it charge.
Another aspect is that a dead/dying battery won't take a full charge, and that can look like charging issues.
Oh and I have the distinct impression your car has a curse on the electrical system.
New Alt. New Alternator harness. New VR.
Battery is the Odyssey race battery that came from your shop last year. No telling how old it is.
And my car decidedly has some sort of gremlins. I'm slowly eliminating them.
Zach
Where have you gotten with this now? Did you find the culprit. I'm going through the same scenario and don't feel like spending what I don't need to spend for parts that are okay.
Not yet.
I've been going through grounds as I am able, but life got a bit busy and my allergies have been HORRIBLE the past couple weeks. Hot and humid or pouring and walking around with my head in a fog. Ugh.
However, I'm currently showing 0 ohms resistance from alt to body and engine to body. Which seems to eliminate grounding as being the issue.
Friday I'm going to buy a new battery. I've replaced or cleaned everything else.
Zach
Posted by: VaccaRabite Sep 7 2018, 02:14 PM
I got a new battery.
Not really any change over the smaller race battery.
So I started playing with the collection of VRs I have recently collected.
Depending on what VR I used, at idle I was seeing a range from 12.3 volts to 13.6 volts. The best results were from a hella solid state VR and an unamed adjustable solid state VR.
With headlights and driving lights on, I’m showing 12.5 at the battery with the better VRs at hot idle.
The voltage still drops when the engine revs, and sits at about 12.3-12.5 volts at 4K.
If I short DF and D+ voltage DOES rise with rpms, and quickly goes up to 17-18volts.
I have gone through all my grounds and currently see 0.000 ohms resistance anywhere. No resistance between engine case and negative battery terminal. None between alternator and engine or alt and body.
My measurements from the battery and the voltmeter on the ECU are different by a volt (ECU sees slightly less voltage then the battery is showing).
I’m left thinking this is just how my car is, and I DO NOT like it. I’m totally stumped, and have run out of things to replace. I think my car is probably fine to drive during the day, but I am afraid to drive it anywhere at night.
Help?
@http://www.914world.com/bbs2/index.php?showuser=3031
@http://www.914world.com/bbs2/index.php?showuser=1143
@http://www.914world.com/bbs2/index.php?showuser=419
PS. I just reread Spoke’s last post and still need to measure voltage between D- and the body. I’ll do that tonight. Now I’m off to the hospital to give comfort to mom.
Zach
Posted by: rjames Sep 7 2018, 02:48 PM
Watching this thread rabidly as my charging system is exhibiting similar behaviors.
Posted by: worn Sep 7 2018, 04:26 PM
I got a new battery.
Not really any change over the smaller race battery.
So I started playing with the collection of VRs I have recently collected.
Depending on what VR I used, at idle I was seeing a range from 12.3 volts to 13.6 volts. The best results were from a hella solid state VR and an unamed adjustable solid state VR.
With headlights and driving lights on, I’m showing 12.5 at the battery with the better VRs at hot idle.
The voltage still drops when the engine revs, and sits at about 12.3-12.5 volts at 4K.
If I short DF and D+ voltage DOES rise with rpms, and quickly goes up to 17-18volts.
I have gone through all my grounds and currently see 0.000 ohms resistance anywhere. No resistance between engine case and negative battery terminal. None between alternator and engine or alt and body.
My measurements from the battery and the voltmeter on the ECU are different by a volt (ECU sees slightly less voltage then the battery is showing).
I’m left thinking this is just how my car is, and I DO NOT like it. I’m totally stumped, and have run out of things to replace. I think my car is probably fine to drive during the day, but I am afraid to drive it anywhere at night.
Help?
@http://www.914world.com/bbs2/index.php?showuser=3031
@http://www.914world.com/bbs2/index.php?showuser=1143
@http://www.914world.com/bbs2/index.php?showuser=419
PS. I just reread Spoke’s last post and still need to measure voltage between D- and the body. I’ll do that tonight. Now I’m off to the hospital to give comfort to mom.
Zach
After a lot of trying along similar lines I bought about six different voltage regulators and found that they pretty much all tended to undercharge. Especially with lights on. I ended up purchasing an adjustable regulator and that solved the problem. Now I have several extra alternators and other electrical system parts that I swapped out along the way. Can’t tell you how nice it is to be able to turn the switch and see about 13 and a half volts going in, plus or minus a bit. My regulator came from a site oriented towards Volvo 1800s.
Hope it works for you soon.
Posted by: FourBlades Sep 7 2018, 07:36 PM
Does the charging problem only happen when the lights are on?
What is the resistance of your lighting circuit?
If it is way low, could it act like a partial short?
Man, I hate chasing electrical gremlins, I feel for you!
John
Posted by: jarodswordmaster Sep 7 2018, 09:26 PM
I can't get any charge out of my alternator with any of the tests so I"m assuming the alternator needs to be replaced.
Posted by: Spoke Sep 7 2018, 09:50 PM
I got a new battery.
Not really any change over the smaller race battery.
So I started playing with the collection of VRs I have recently collected.
Depending on what VR I used, at idle I was seeing a range from 12.3 volts to 13.6 volts. The best results were from a hella solid state VR and an unamed adjustable solid state VR.
With headlights and driving lights on, I’m showing 12.5 at the battery with the better VRs at hot idle.
The voltage still drops when the engine revs, and sits at about 12.3-12.5 volts at 4K.
If I short DF and D+ voltage DOES rise with rpms, and quickly goes up to 17-18volts.
I have gone through all my grounds and currently see 0.000 ohms resistance anywhere. No resistance between engine case and negative battery terminal. None between alternator and engine or alt and body.
My measurements from the battery and the voltmeter on the ECU are different by a volt (ECU sees slightly less voltage then the battery is showing).
I’m left thinking this is just how my car is, and I DO NOT like it. I’m totally stumped, and have run out of things to replace. I think my car is probably fine to drive during the day, but I am afraid to drive it anywhere at night.
Help?
@http://www.914world.com/bbs2/index.php?showuser=3031
@http://www.914world.com/bbs2/index.php?showuser=1143
@http://www.914world.com/bbs2/index.php?showuser=419
PS. I just reread Spoke’s last post and still need to measure voltage between D- and the body. I’ll do that tonight. Now I’m off to the hospital to give comfort to mom.
Zach
About the voltage measurement from D- to chassis, connect the negative lead to the chassis post beside the relay board. You should read 0.0V since the alternator case is bolted to the fan shroud which is bolted to the engine case which is bolted to the transmission which is strapped to the chassis post under the trunk. All should be 0.0 ohm connections. The strap does have finite resistance which is proportional to its length; maybe 10 mOhm.
A loss of even 1V with the ground will greatly affect the charging circuit. I doubt this is an issue but we've got to cross off all variables. With the charging problems you've been having, something in the charging system is definitely wrong. You haven't found it yet. It shouldn't be the battery, alternator, or VR since you've changed all these items and the system still isn't right.
Which VR gave 13.6V at idle? Seems that VR is the best candidate seeing that you can get high voltages when DF is shorted to D+.
With DF shorted to D+, do you see the same drooping of voltage when revving the engine?
Which VR gave the drooping voltage you quoted?
Posted by: Spoke Sep 7 2018, 09:58 PM
I can't get any charge out of my alternator with any of the tests so I"m assuming the alternator needs to be replaced.
Is the GEN light on when the engine is running?
What voltage do you read on the battery with DF shorted to D+?
Posted by: jarodswordmaster Sep 8 2018, 08:41 AM
I can't get any charge out of my alternator with any of the tests so I"m assuming the alternator needs to be replaced.
Is the GEN light on when the engine is running?
What voltage do you read on the battery with DF shorted to D+?
Yes, the gen light is on when the engine is running, same volts running and not running, 12.6. when I short DF to D+ I get no change in the voltage. I'll run through all the tests again today. I short DF to D+ with all connections still made between the alternator, relay board and VR correct?
Posted by: Spoke Sep 8 2018, 08:48 AM
I can't get any charge out of my alternator with any of the tests so I"m assuming the alternator needs to be replaced.
Is the GEN light on when the engine is running?
What voltage do you read on the battery with DF shorted to D+?
Yes, the gen light is on when the engine is running, same volts running and not running, 12.6. when I short DF to D+ I get no change in the voltage. I'll run through all the tests again today. I short DF to D+ with all connections still made between the alternator, relay board and VR correct?
Remove the VR then short D+ to DF. Measure the voltage from DF/D+ to chassis. Should be the same as the battery voltage. If not, the alternator is suspect.
When did this change from working correctly to not working correctly? Did you check the alternator belt for tightness?
Posted by: jarodswordmaster Sep 8 2018, 08:59 AM
I can't get any charge out of my alternator with any of the tests so I"m assuming the alternator needs to be replaced.
Is the GEN light on when the engine is running?
What voltage do you read on the battery with DF shorted to D+?
Yes, the gen light is on when the engine is running, same volts running and not running, 12.6. when I short DF to D+ I get no change in the voltage. I'll run through all the tests again today. I short DF to D+ with all connections still made between the alternator, relay board and VR correct?
Remove the VR then short D+ to DF. Measure the voltage from DF/D+ to chassis. Should be the same as the battery voltage. If not, the alternator is suspect.
When did this change from working correctly to not working correctly? Did you check the alternator belt for tightness?
my son and i are working on reassmbling a rust bucket that everything had been gutted except for the wiring harness to strip for painting. So, this alternator hasn't been proven out to get good yet. I don't recall if it was the one I had on this engine 4 years ago when I pulled it from the 72 we sold. It's all a blurr now as to what I swapped when I put the 1.7l back in the 72 and sold it. I kept the 2.0l and side shifter for the 76 it belongs to that we are working on now. I'm pretty sure I have the circuit complete for charging. Just want to make sure before spending money on the wrong part.
Posted by: VaccaRabite Sep 8 2018, 03:06 PM
I’m back to grounds.
And I’m going to put a new battery in my multimeter, as it’s lying to me somehow on Ohms. It’s gotta be.
Just did the DF shorted to D+ test, measuring voltage from D- to chassis. I picked 2 spots to measure. Both showed a voltage of (drumroll please...)
1.6 volts.
Yesterday, and today, I was showing zero resistance between any points on the car. But I have a voltage drop of about 1.7 volts. It danced around a little bit settled between 1.6 and 1.7.
Something is resisting somewhere.
This would also probably match with the voltage difference in seeing when I measure the battery and what the ECU says it’s seeing on my testing laptop, as the ECU is seeing less.
Another curious note. The red Gen light comes on at key in, goes off when the engine starts, and stays off when I pull the VR out of its slot. Should it do that, or should it light up again to alert me that something is not charging?
Zach
Attached thumbnail(s)
Posted by: Spoke Sep 8 2018, 04:13 PM
I’m back to grounds.
And I’m going to put a new battery in my multimeter, as it’s lying to me somehow on Ohms. It’s gotta be.
Just did the DF shorted to D+ test, measuring voltage from D- to chassis. I picked 2 spots to measure. Both showed a voltage of (drumroll please...)
1.6 volts.
Yesterday, and today, I was showing zero resistance between any points on the car. But I have a voltage drop of about 1.7 volts. It danced around a little bit settled between 1.6 and 1.7.
Something is resisting somewhere.
This would also probably match with the voltage difference in seeing when I measure the battery and what the ECU says it’s seeing on my testing laptop, as the ECU is seeing less.
Another curious note. The red Gen light comes on at key in, goes off when the engine starts, and stays off when I pull the VR out of its slot. Should it do that, or should it light up again to alert me that something is not charging?
Zach
The GEN light staying off when the VR is out is expected. The 2nd set of diodes in the alternator generates a voltage equal to the battery voltage.
About the 1.6V, try running a wire from the generator body to the engine case.
Posted by: VaccaRabite Sep 8 2018, 05:17 PM
Goddamn happy dance.
14 volts at idle.
14 volts at 4K rpm.
Using either of the single piece solid state VRs. Using the pig tailed solid state VR showed 13.5v. And the mechanical VR I got from Bruce was dancing from 13.5 to 14V.
It was a grounding issue. I went back through the grounds, recleaned them, and added a 10 gauge wire from the alternator case to the chassis ground under the relay board. (I was doing that as you posted Spoke).
Damn, that was a tough one. Still don’t know why the grounding issue was happening, as the meter said I was golden. But, clearly, the meter was wrong.
Zach
Posted by: VaccaRabite Sep 8 2018, 05:20 PM
I’m going to put the race battery back in and check that. I suspect it will be fine, and I’d like to use this battery on another vehicle that needs a battery. So the Toyota will, again, steal a battery from the 914, and the Toyota battery will be the core battery that goes back to FLAPS.
ZACH
Posted by: Spoke Sep 8 2018, 10:06 PM
Goddamn happy dance.
14 volts at idle.
14 volts at 4K rpm.
Awesome!
Posted by: ClayPerrine Sep 9 2018, 05:34 AM
Goddamn happy dance.
14 volts at idle.
14 volts at 4K rpm.
Using either of the single piece solid state VRs. Using the pig tailed solid state VR showed 13.5v. And the mechanical VR I got from Bruce was dancing from 13.5 to 14V.
It was a grounding issue. I went back through the grounds, recleaned them, and added a 10 gauge wire from the alternator case to the chassis ground under the relay board. (I was doing that as you posted Spoke).
Damn, that was a tough one. Still don’t know why the grounding issue was happening, as the meter said I was golden. But, clearly, the meter was wrong.
Zach
That's great!!!
I never really thought about it before, but adding a heavy brown wire to the alternator harness and running it back to the ground point at the relay board is a really good idea.
Posted by: bdstone914 Sep 9 2018, 08:53 AM
Zach,
Are your alternator mounting brackets painted of plated ? I have heard that painted brackets interfere with the grounding.
Is that using the alternator and VR I sold you?
Bruce
@http://www.914world.com/bbs2/index.php?showuser=1435
Posted by: Spoke Sep 9 2018, 11:26 AM
Damn, that was a tough one. Still don’t know why the grounding issue was happening, as the meter said I was golden. But, clearly, the meter was wrong.
Zach
I took apart an engine once and the alternator had a braided strap on it connected to a bolt on the engine case. You did yours one better by connecting the alternator case directly to the chassis instead of the engine case. I wonder what the D- to chassis voltage is now? If you get a chance, measure D- again to see the difference from the previous measurement.
Looking at the engine w/o the tin it became obvious that all the alternator current flows through the alternator case to the fan shroud, then from the fan shroud to the engine case via the 4 small studs holding the shroud to the case. If the shroud is painted or powder coated, the coatings could interfere with the alternator case grounding causing issues like you've experienced. The alternator brackets if painted/powder coated could also cause resistance. The coatings should be scraped off or masked off during application. Best solution is to run a wire from the alternator case to the chassis.
It's very difficult to get an accurate resistance measurement when the resistance is much less than about 1 ohm. At sub ohm resistances, even the resistance of the probes need to be included. The best way to measure a low resistance like this is to put current through the resistor and measure the voltage.
Posted by: VaccaRabite Sep 9 2018, 02:50 PM
Zach,
Are your alternator mounting brackets painted of plated ? I have heard that painted brackets interfere with the grounding.
Is that using the alternator and VR I sold you?
Bruce
@http://www.914world.com/bbs2/index.php?showuser=1435
I’m fairly sure this was the issue.
All the tins and my fan shroud were powder coated. The studs were taped off, but the slider part of the shroud wasn’t. So I’m guessing there was resistance there.
What is confusing is how my meter was showing no resistance. Granted, I was measuring this with the engine off, and maybe that was the problem. It would start showing a little resistance, maybe an ohm, but then would quickly go to 0.000 resistance.
And now I have a collection of spare voltage regulators if I ever need them. Lol.
Zach
Posted by: VaccaRabite Sep 9 2018, 03:41 PM
I took apart an engine once and the alternator had a braided strap on it connected to a bolt on the engine case. You did yours one better by connecting the alternator case directly to the chassis instead of the engine case. I wonder what the D- to chassis voltage is now? If you get a chance, measure D- again to see the difference from the previous measurement.
I’m still loosing 140MV, which isn’t much.
And while DF and D+ are set for max effort, I’m now pushing 17 volts at warm idle (1100rpm) instead of the 14 volts I had been pushing at idle.
It’s really night and day after running the big bore ground cable from the alternator to the chassis.
Zach
Posted by: worn Sep 9 2018, 06:56 PM
Goddamn happy dance.
14 volts at idle.
14 volts at 4K rpm.
Using either of the single piece solid state VRs. Using the pig tailed solid state VR showed 13.5v. And the mechanical VR I got from Bruce was dancing from 13.5 to 14V.
Zach
Great news. Really glad you ran it down.
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