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Posted by: b.stirbu Aug 9 2015, 04:14 PM

Dear 914ers,

I'm quite in a pickle with my 914 1.7.

The engine sometimes starts sometimes not (usually after it started, ran 5-10 seconds and then stopped and I couldn't manage to start it again).
Messing arround in the engine compartment I accidentally unplugged the cyl 4 fuel injector and surprise the engine started and idled low. Tried again one, two, three times and he started succesfully, but as soon as I plug back the cyl 4 injector cable does not want to start again...

What's wrong here? (the injector not, because I've swapped 3 with 4 and I still had the same problem). According to the attached current flow cyl 4 injector is in series with the cold start valve and the thermoswitch for the cold start valve.. Am I looking at the right diagram? I also don't know where current track 102 comes from.


Also very interesting is that I removed the injectors 3 and 4 and placed them in two cups to see if they work, and I could start the engine in two cylinders (although the cyl 4 injector plug was connected)

Cheers,
Bogdan


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Posted by: Jeff Bowlsby Aug 9 2015, 04:29 PM

Hi Bogdan, Welcome to 914world!

A couple of things first off:

You have the schematic for the 1974 2.0L, but you have a1973 1.7L. Do you have the correct schematic?

The cyl 4 injector is not in series with the CSV or the thermoswitch. While these are in the fuel injection harness, they are not controlled b the ECU, rather they are in a circuit powered directly from the relay board.

Posted by: Dave_Darling Aug 9 2015, 10:02 PM

The injector on track 102 is not the #4 injector. It's just the cold-start valve, and it grounds through the thermo-switch (often called the thermo-time switch). The switch is grounded (the thin line to the bottom of the page). The CSV gets its power from one of the pins in the four-pin plug on the relay board.

As Jeff notes, the 70-71 1.7 wiring diagram should be a better match for what you have in your car. I believe that the parts of the circuit I describe above are the same for yours, though.

--DD

Posted by: Valy Aug 9 2015, 11:39 PM

The qire diagram is not much different, especially not for the injection part you are looking at.
I would check the cable that leads to #4.
Sounds to me like there is a short on that cable. See if there is any damage along the cable.

What happend just before this started to happen?

Bine ai venit la noi in club! Succes cu reparatia.

Posted by: b.stirbu Aug 10 2015, 12:45 AM

Guys, thanks for your replies. Multumesc frumos Vali!

I have no history of the car. I believe it was not used since 1990, but it was stored inside.

There was a lot of gas in the oil and also had problems starting.. The initial owner passed away.. I believe he also had this problem and tried so much to start it that he injected all that gas in the cylinders.
When I opened only the long block, and the rings where still looking good and the valves the same, no signs of lowered seat..
I am certain that's a electrical problem..
I interpreted the diagram in the wrong way. The IV on the diagram is related to the relay board 4 pin connector.

I've tested the other injecto connectors for continuity between both wires and they all buzz, that's rather strange..

I could draw two conclusions from this situation:
-The cyl 4 injector cable is faulty or cyl 4 electronics in the EFI are faulty and as soon as the solenoid is energised it affects the other cylinders also
-The fault in the wiring affects the spark...

Posted by: euro911 Aug 10 2015, 04:14 AM

Hello Bogdan. ECUs are fairly bullet-proof, but anything is possible.

I see that Jeff Bowlsby has already responded, but have you checked out the trouble-shooting guides on his Tech Notebook site? ... If not, http://bowlsby.net/914/Classic/TechNotebook.htm for a wealth of information

... and

Posted by: Valy Aug 10 2015, 08:56 AM

There are 2 things I woud check more:
1. Make absolutely sure that the spark plugs are connected in the correct order. More specifically, does it start if you disconnect spark plug #4?
2. I'm almost sure you can mix the injection wires around. Check what happens when you switch between #4 wire and some other wire.

Posted by: b.stirbu Aug 10 2015, 12:10 PM

Update. If I build up fuel pressure first and then remove the fuel pump relay the car starts.. I tried to power the fuel pump from an external power supply and still did not started or at least tried... Is there a fuel pressure problem?
Vali, i tried to remove the #4 spark plug cable but does not want to start without it.

Posted by: b.stirbu Aug 10 2015, 12:31 PM

Should the fuel pump be electrically isolated from the body? I replaced the plastic fuel lines with copper ones...

Posted by: Valy Aug 10 2015, 12:34 PM

the pump is not isolated from the body.
did you try to switch the injector wires?

Posted by: SLITS Aug 10 2015, 12:45 PM

The fuel pressure should be in the 28 - 32 psig range for proper operation. If to high (blocked return line or misadjusted pressure regulator) it can override the spring in the injector and flow fuel constantly (flooding the engine). Since you said that you built pressure and then removed the fuel pump relay and it started ... I would look at your fuel pressure first.

Posted by: b.stirbu Aug 11 2015, 02:36 AM

Yes, it did not started.

I will install a pressure gauge and then test again.
I find it strange that it starts on 3 cylinders with the pump running and on 4 cylinders with the pump off..
I'm pretty sure there is a short circuit somewhere.
I've checked the pump power cables, and they buzz if the 12 pin connector is connected to the relay board...is that normal??
Does the short circuit comes from the coil?

Posted by: Valy Aug 11 2015, 08:50 AM

Ok. Did you try to disconnect the new #4 wire or the injector connected to old #4 and start.
This will isolate the culpit to the injector or wire.

Too much pressure can hold the injector open but you said you tested them outside the car. Also, why is it a problem only when the wires are connected?

Posted by: b.stirbu Aug 12 2015, 04:20 AM

The injector is not the problem, because I've swapped the injectors. And i also know they work...I need to dig into this?


Is it normal that the fuel pump cables are buzzing(like they are short circuited?

Posted by: Dave_Darling Aug 12 2015, 08:42 AM

What do you mean "buzzing"? Making a sound like a bumble-bee? Triggering the "yes these are connected" sound in your electrical multimeter when you measure across the wires? Something else?

--DD

Posted by: b.stirbu Aug 12 2015, 03:37 PM

Dave, yeah it detects that fuel pump wires are connected. I do not find that a healthy sign...it detects this only if the 12 wire connector is connected to the relay board.

Posted by: b.stirbu Aug 16 2015, 01:22 AM

Ok, the fuel pressure regulator is stuck closed...I've pressurized the fuel line, started the engine and the pulsed (from another battery) from time to time the fuel pump to keep the engine running...it seems to be ok, I think I just need to tune the ignition timing..
During initial troubleshooting I did not consider at all the fuel pressure regulator as being faulty. Everywhere I read, everybody says that is a very reliable..I guess after
20 years of being unused he also cosidered retiring..

I've noticed something rather intersting for me.. if I pulse too long the fuel pump the engine starts to run around 3000 for 10-15 seconds like it was creating a vacuum on the fuel line and also engaging the fuel pump...

Posted by: Tom Aug 16 2015, 06:41 PM

I would check injector #4 with an ohm meter to see if it is shorted, pulling down the ECU signals to all of the injectors.
Tom

Posted by: b.stirbu Aug 18 2015, 03:36 PM

Hij doet het!!!
The little beast starts. Ha ha!
But! as always... there is always a but, it idles around 3000rpm....niet goed..
I've unplugged the AAR suction from the air intake and placed my finger on the hose...the rpm drops to 1500....and it feels like a 2000w vacuum cleaner...
Is that normal?

Posted by: Valy Aug 18 2015, 03:49 PM

The vacuum is normal and good.
The AAR should close after the engine warms up.
The idle is high. Something is not tuned right or you have some air leaks.

Posted by: b.stirbu Aug 18 2015, 04:23 PM

If I got it right, the ideal cold start rpm with the AAR open is ~1800.
The AAR is open... if it closes after the engine gets warm I do not know.. I have not tested it yet.

I will recheck for vacuum leaks...

Posted by: Dave_Darling Aug 18 2015, 07:37 PM

Usually a 3000 RPM idle is a large vacuum leak. As in, one of the hoses to the plenum fell off.

--DD

Posted by: b.stirbu Aug 19 2015, 03:44 AM

Hi Dave,

It drops to 1500 rpm if I close (clog) the AAR suction with my finger... it should drop to ~900, so I need to find out where the rest of the RPM comes from..
I think I need to look also at the brain knob..I played with that earlier....

Most likely there is a vacuum leak, because I can hear a suction sound (like air being sucked through a small crack)..

Posted by: Dave_Darling Aug 19 2015, 09:19 AM

The brain knob only fiddles the idle mixture--not the idle RPM. At least, not directly.

500 RPM could be caused by ignition timing (is the car hard to start?) as well as by vacuum leaks.

--DD

Posted by: euro911 Aug 19 2015, 01:14 PM

Check all vacuum connections for leaks (repair/replace as needed) *
Verify/adjust valve clearances *
Verify/adjust dwell angle *
Check trigger points * (clean contacts & lube shaft - or replace as needed)
Verify/adjust ignition timing *
Verify functionality of individual components (which I believe you've already done - repair/replace as needed)

* (if not already done)

There is also an adjustment on the throttle body but should be the last item to adjust after performing the steps above.

I did all these things to get my wife's 1.7L to run (and idle) properly. Unfortunately, I did everything at once, so I never determined if any one of them by itself corrected the problem.

Posted by: b.stirbu Aug 29 2015, 07:17 AM

Thanks guys for your help until now.

I'm running into something that baffles me...
The valves are adjusted, dwell angle is 45, ignition timing set with the timing light at 3500 rpm, new spark plugs, new fuel pump, all the injectors have been cleaned and they spay (i've rotated them around the cilinders) and I'm still always running on 2 cilinders: 4 and 2..
What can it be ?
-No Vacuum? I doubt because the mix reaches the cilinder head...
-The valves are adjusted wrong? At least the intake valves opens (the sparkplugs are wet)
I doubt the cam shaft lobes are worn because when I adjusted the valves the were moving nicelly...

The sparks for cylinder 1 and 3 spark outside the engine, but seem to not do it when I fit them in...
when I took the sparks out they were nicely wet...

Posted by: 914itis Aug 29 2015, 08:54 AM

For this issue you have to check your trigger points at the distributor .

Posted by: Dave_Darling Aug 29 2015, 09:48 AM

Double-check your injector grounds. They are paired, though I forget which two share a ground.

Trigger points are paired diagonally across the engine, so 1/4 and 2/3. So the trigger points aren't a likely suspect, unless the injector wires have been swapped on one side of the engine. (Not that hard to do, though. Hmm. The engine will still run OK with them swapped...)

Grounds first, then trigger points. That would be what I checked.

--DD

Posted by: b.stirbu Aug 29 2015, 11:17 AM

the ground are OK, and I'think the injectors are all working properly..I've tested them outside the intake in some cups. They all sprayed an equal quantity of gas Either they are all faulty or all good..

Now the interesting part comes...The intake for the cilinders that are not operating are Warm...(warmer than the ones that operating)

the Exaust of the cilinders that do not operate is cold..it makes me think that either the valves are not adjusted properly for this two cilinders...

What makes an intake pipe warm?

Posted by: Valy Aug 29 2015, 05:28 PM

1. Could it be you mixed the spark plug wires between the non-working cylinders?
2. What happens if you try to start it with just the 2 non-working injectors wired? Do you get backfire from the intake?

Posted by: euro911 Aug 29 2015, 06:11 PM

Pardon me if I missed anything you or others previously posted.

You said you timed it @3500 RPM, so it was running OK at some point. Did you make sure to tighten up the dizzy afterward? ... is it possible that it moved?

Are you still seeing 45° dwell angle?

The dizzy rotates CCW, are you SURE you have the firing order correct? (1-4-3-2)

Did you try static timing it @ around 7% BTC to see if you can get it started again

Just tossing out suggestions ...

Posted by: b.stirbu Sep 2 2015, 12:16 AM

Guys, first of all, I would like to thank you for you help and ideas.
With all the shame I have to share my story, maybe it can be a lesson learned for other 914ers (and not only).

When I changed the piston rings I also removed the rocker arms (and rods), in order to inspect them.
When I fit the rocker arms back, I've must have done something wrong with the torque settings (or the wrench is not properly calibrated), because:

- On cilinder 1 - one nut jumped off and one was loose
- On cilinder 3 - both nuts jumped off...

Luckily the rocker arms are held in place by that wire underneath them...

After I've tight them back (I might have tight them a bit too hard) and readjust the valves, the car started from the first turn of the key..

I could not sleep last night thinking that I'm so close of driving it...
It idles ok, it might need a bit of tunning, and I think I have to tune the throttle, because after acceleration I have to push is back a bit to decrease the RPMs..

Posted by: euro911 Sep 2 2015, 01:09 AM

Glad to hear you found and fixed the problem

You can lightly lube the throttle shaft on the throttle body and the throttle cable where it enters the sheath in the engine compartment to help with the lagging throttle return.

Also check to see if your return spring has enough tension to pull the throttle plate fully closed. You may need to replace the spring or find another anchor point to attach it to.

Posted by: Dave_Darling Sep 2 2015, 09:01 AM

The torque on those is pretty light, I believe 11 lb-ft. But the trick is that you have to tighten them when the cylinder is at TDC, so the valves are not pushing on the rocker arms! The valve springs will push the rockers enough that the rocker shafts won't even seat against the head at 11 lb-ft.




Check the pedal, especially if it wobbles at all. Rust can get into the rubber pedal and rot out the metal hinge that is inside it. That will make it wobble and stick.

If that's not the problem, then unhook the throttle linkage where you can and try to isolate where the problem is. It could be in the cable, at the pedal, otherwise at the pedal cluster, or at the throttle body itself.

--DD

Posted by: Bob L. Sep 2 2015, 11:19 AM

Also, make sure the throttle cable isn't wrapped around or bound up with the clutch cable.

Posted by: b.stirbu Sep 6 2015, 04:56 AM

I think I've got a serious problem now...I can drive the car in the 1st and reverse gear, but when I switch into the 2nd to 5th gear the lever switch just pops out back to neutral...I've tried to force hold it in the 2nd gear and it makes a very loud gear box specific sound..
I'm not sure if this is a clutch related problem or gear box problem...

Posted by: euro911 Sep 6 2015, 07:31 AM

Have you checked all the shift rod bushings?

One in the front shift rod support bracket under the shift lever assembly in the tunnel
One at the fire wall
One spherical on the shift pivot bolt at the connection to the rear shift rod
One spherical in the front of the rear shift rod
One in the rear shift rod support bracket

EDIT:

The condition you describe is pretty common when the bushings need replaced. Mark the positions of the shift rod connection at the rear of the tunnel prior to disassembling anything. It will save you a lot of time getting the shift adjustment back to normal.

If you don't already have the 914 PET Katalog, download the .pdf file here: http://www.porsche.com/all/media/pdf/originalparts/en/E_914_KATALOG.pdf

Posted by: b.stirbu Sep 7 2015, 05:26 AM

I will check, but I'm afraid it's not a rod bushing problem..otherwise I can't explain why 1st and reverse gear work properly..

Posted by: rhodyguy Sep 7 2015, 09:07 AM

same jump out of gear problem while engaging 3rd&4th?

Posted by: b.stirbu Sep 7 2015, 12:31 PM

2nd,3rd,4th,5th...the synchronized gears....