Now I’m overcharging, My car is murdering voltage regulators Options

[VaccaRabite]

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I’ve been driving my car all over for the past week or so.
Last weekend I noted that it was hard to start, and it stalled while pulling away in 1st once. Weird. Didn’t worry about it and finished my drive.

Got home and I checked voltage at the battery and I was making 18 volts, my VR had seemed to fail and I was pushing max voltage at the battery. Geeze, no wonder the car was hard to start with the alternator at max effort.

So, I’ve done the ground thing and they are all clean and good. In my undercharging thread I ran a 10ga wire from the alternator case to the body ground point near the relay board in the engine bay.

I’ve also checked all my collection of voltage regulators and all 5 of them, be they mechanical or solid state are now allowing the alternator to go full bore all the time.

This is with both the brand new battery and the PC680 gell cell race battery.

What do I look for now? Could I have broken the VRs by pulling them off the running car while chasing issues with the alternator last time? Or is this a car thing and I need to fix something else.

The car is essentially acting like I have D+ and DF jumped with D- left empty.

Zach

[Spoke]

Did you find a 666 tattooed somewhere on your car?

If you pull the VR (with the engine off), does the alternator quit charging?

[VaccaRabite]

Did you find a 666 tattooed somewhere on your car?

If you pull the VR (with the engine off), does the alternator quit charging?

Yes. Pull the VR and the idle picks up and the battery quickly dips down to about 12.8 volts.

Zach

[Dr Evil]

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[porschetub]

(IMG:style_emoticons/default/beer3.gif) (IMG:style_emoticons/default/beer3.gif) (IMG:style_emoticons/default/beer3.gif)
I’ve been driving my car all over for the past week or so.
Last weekend I noted that it was hard to start, and it stalled while pulling away in 1st once. Weird. Didn’t worry about it and finished my drive.

Got home and I checked voltage at the battery and I was making 18 volts, my VR had seemed to fail and I was pushing max voltage at the battery. Geeze, no wonder the car was hard to start with the alternator at max effort.

So, I’ve done the ground thing and they are all clean and good. In my undercharging thread I ran a 10ga wire from the alternator case to the body ground point near the relay board in the engine bay.

I’ve also checked all my collection of voltage regulators and all 5 of them, be they mechanical or solid state are now allowing the alternator to go full bore all the time.

This is with both the brand new battery and the PC680 gell cell race battery.

What do I look for now? Could I have broken the VRs by pulling them off the running car while chasing issues with the alternator last time? Or is this a car thing and I need to fix something else.

The car is essentially acting like I have D+ and DF jumped with D- left empty.

Zach

I wasn't aware the could achieve 18volts I was always thinking they topped out @ 16volts ,your altenator must be heathy,have you checked for continuity across D+ and DF on your regulators ? could you have a dead short across those pins on your relay board maybe? its unlikely you could have 5 bad regulators but who knows,have you tried a new one?.
Hopefully you haven't damaged your batteries,I had a charger that killed one of my batteries....boiled the snot out of it (IMG:style_emoticons/default/sad.gif) .
Good luck sorting this (IMG:style_emoticons/default/beer.gif) .

[Spoke]

If want me to test the VRs, I'll check them out on my car. It would be strange that 5 VRs are bad but who knows.

[VaccaRabite]

@spoke
Send me your address and I’ll send a VR care package.

I suspect it’s not really the VR, but would be good to cross that off the list.

Is it possible that by grounding the alt case directly to the chassis I have done an end run around something which is causing this issue?

Zach

[toolguy]

@spoke

Is it possible that by grounding the alt case directly to the chassis I have done an end run around something which is causing this issue?

Zach

Isn't an alt case already grounded to the chassis via the normal mounting bolts ???

[Spoke]

@spoke
Send me your address and I’ll send a VR care package.

I suspect it’s not really the VR, but would be good to cross that off the list.

Is it possible that by grounding the alt case directly to the chassis I have done an end run around something which is causing this issue?

Zach

Grounding the alt case to the chassis should not cause an issue. The normal alt case grounding goes from the alt case >> Fan shroud >> engine case >> transmission >> trans strap >> chassis.

You have the alt case strapped directly to the chassis. Either way should be milliohms and should not be an issue. If you want to feel better about it, use a very short cable and ground the alt case to the engine case.

PM sent with my contact info. If you ship USPS flat rate small box it'll cost about $7 and I can get it this weekend and test. I'll just put them in my 914 and see what happens. My current VR/alt gives a rock solid 14.0V from idle to max RPM.

[IronHillRestorations]

What about your alternator warning light? Sorry I didn't go back and read all the old thread

[Spoke]

@spoke

Is it possible that by grounding the alt case directly to the chassis I have done an end run around something which is causing this issue?

Zach

Isn't an alt case already grounded to the chassis via the normal mounting bolts ???

Yes, that's the theory. The alt case is grounded via:

alt case >> Fan shroud >> engine case >> transmission >> trans strap >> chassis.

In Zach's car the fan shroud and alt hanger were powder coated which caused probably only 0.5 ohm of resistance or less. 1/2 ohm doesn't sound like much but for example run 2 amps through 0.5 ohm and it drops 1V.

The VR should hold the alt voltage to 14V so losing 1V means 13V at the battery. Turn on the headlights and the draw goes to 5-10A and the battery discharges while driving.

[VaccaRabite]

What about your alternator warning light? Sorry I didn't go back and read all the old thread

Depends on the VR used.

For the solid state VRs the light will remain lit until the engine revs to about 1000 RPM and then go out, so it stays on for about 1/2 second on start up.

for the mechanical VRs the light goes out as soon as the car turns on.

In all cases the light does go out, which makes sense as the car is in fact charging. Just too much at this point.

Zach

[Spoke]

What about your alternator warning light? Sorry I didn't go back and read all the old thread

Depends on the VR used.

For the solid state VRs the light will remain lit until the engine revs to about 1000 RPM and then go out, so it stays on for about 1/2 second on start up.

for the mechanical VRs the light goes out as soon as the car turns on.

In all cases the light does go out, which makes sense as the car is in fact charging. Just too much at this point.

Zach

What you are seeing with the GEN light is normal. The 1/2 second start up is the time it takes for the VR/alt to bootstrap itself and start running normally.

[Peashooter]

Take off your relay board and take a look at the bottom. On my previous car the board had been repaired after the insulation failed and the repair material was slightly conductive, leading to exactly the same issue you have with overcharging. Good luck!

[VaccaRabite]

Take off your relay board and take a look at the bottom. On my previous car the board had been repaired after the insulation failed and the repair material was slightly conductive, leading to exactly the same issue you have with overcharging. Good luck!

Just put a new relay board in it a few weeks ago while trying to find the cause of the undercharging issues.

Part of the reason why this is frustrating is that I have replaced or cleaned every part of the charging system over the past month.
*new alternator
*new alternator harness
*new relay board
*several new voltage regulars
*cleaned all the engine compartment grounds, and added a heavy ground from alternator case to the chassis.


Zach

[Spoke]

Take off your relay board and take a look at the bottom. On my previous car the board had been repaired after the insulation failed and the repair material was slightly conductive, leading to exactly the same issue you have with overcharging. Good luck!

Just put a new relay board in it a few weeks ago while trying to find the cause of the undercharging issues.

Part of the reason why this is frustrating is that I have replaced or cleaned every part of the charging system over the past month.
*new alternator
*new alternator harness
*new relay board
*several new voltage regulars
*cleaned all the engine compartment grounds, and added a heavy ground from alternator case to the chassis.


Zach

Keep in mind that you have made progress. Instead of under-charging the system can now charge correctly. Why the VRs aren't behaving is unknown at this time.

It's like you've moved the goal posts closer by 10 yards and moved the kicker back by 5 yards. Keep the faith; you'll figure it out eventually.

[VaccaRabite]

I've been reading online that voltage regulators can be killed by voltage spikes. So there is decent chance that I just plain old killed them by swapping them out so much while testing the car over the past month, seeing as how the car was running when I'd pull the VR to short DF to D+. Or swapping the VRs areound when I thought the issue may have been with the VR before I ran the ground wire.

I was mean to them.

Zach

['73-914kid]

What brand voltage regulators are you using? I had purchased a new Beru brand VR for my 6 and killed it in 80 miles.. was charging at 16.8V. Being 2 hours from home I stopped at auto zone and they had a duralast regulator in stock. Part number VR650. It has worked flawlessly for the last 3 or 4 years.

I've installed these in 3 other 914s and have been extremely pleased with them. Nice stable voltage, and they're cheap and easy to get your hands on.

[VaccaRabite]

What brand voltage regulators are you using? I had purchased a new Beru brand VR for my 6 and killed it in 80 miles.. was charging at 16.8V. Being 2 hours from home I stopped at auto zone and they had a duralast regulator in stock. Part number VR650. It has worked flawlessly for the last 3 or 4 years.

I've installed these in 3 other 914s and have been extremely pleased with them. Nice stable voltage, and they're cheap and easy to get your hands on.

Mixed bag of brands, but I don't know that any were Auto Zone Duralasts. AutoZone is my local FLAPS so I may run over after work to see if they have one. I think the same company makes the house brand stuff for AutoZone and all the other big chains, and there is a NAPA and the other Red and Yellow store across the street, so I'll check there too.

Zach

[Dr Evil]

Electrically, the only way this could happen is if the VR is allowing for max voltage at DF which then caused the alternator to juice out max amps. Something that would cause this would be a ground in the feed to the VR indicating that the system was in need (maximum need). But your bulb is working and it couldnt if there was a ground. This happened after a new board? Did I understand that correctly?

I always thought that when VR fried they went to low volts on the DF?