87 GTI Cold Idling Problems

[JRKman]

I have an 1.8 L 8v 87 GTI with CIS-E. When I go to start my car cold, more often then not it will start and act like it is idling on 3 cylinders. It never needs cranking to start. When I rev it, it still acts like it is running on 3 cylinders.

If I immediately drive off, it has no power, still "runs of 3 cylinders" and will do this for a while until it reaches operating temp, then it will disappear. If I let it idle (idles around 800-1000 rpm) it will still have the same symptoms but will reach temp quicker (5-10 minutes) and then the problem will disappear.

You can can hear the problem go away. It goes from sounding like a harley to idling very smooth. All the power will come back and it will run perfectly.

I checked the coolant temp sensor. It read about 1350 ohms (80-100F) after it had been sitting for a couple hours so that seems to check out fine.

Any ideas??

[JRKman]

So far from reading my eyeballs out, it could be a ground issue. I have the exact same symptoms as this guy in this thread down to the smallest detail.

In the 4th to last post he explains the problem. Does anyone have a picture of the ground he is talking about or where I can find the grounds?

-Josh

[elementsoffury]

Mine used to do the same thing. No cranking, it would just fire up and bog or die a few times. Now it takes a few cranks and then bogs or dies a few times.

This is a very hard problem to fix, and I would almost bet that 99% of cis-e behave this way at cold start. My car has been doing it for the 10 years I've owned it. Though if I wait the 2 minutes and let it idle; it'll be fine.

The ground is just a braided strap that goes from the valve cover (by dizzy) to one of the coil mounting bolts I believe. Do a quick test with a piece of regular wire and then go

I think the cause has more to do with the 3 wire potentiometer on the other side of the fuel dizzy from the DPR than anything. I tried to adjust mine, but I believe you need the mythical plate holder tool or somehow find out the proper measurements of the plate location at idle.

[JRKman]

Do you know where I can find instructions on how to set it up/adjust it?

[elementsoffury]

Do you know where I can find instructions on how to set it up/adjust it?

In the bentley manual

One of the first few steps is to place special tool on the dizzy plate and then you have to make your own harness or buy another special tool.

Someone on here actually posted a pic of that plate tool on here not too long ago. Maybe we can get him to take some measurements or rent it out.

[JRKman]

So I was tinkering around while it was doing its thing this morning. If I pull the spark plug wire to the cylinder 2nd closest to the belts, the nasty idle smooths out a good bit. You can still tell its running off three cylinders because it is, but it isn't nearly as rough of an idle. Still goes right away when warm. Any ideas?

[JRKman]

Does anyone have any idea? I would appreciate the help :/

[JRKman]

So I checked the current through the dpr. When I start the car cold, it's at about 16-18mA an when it is running operating temp, it is averaging 11.5-12mA. Anyone know what that tells me?

[elementsoffury]

It should go up to like 50ma for the first 30 seconds or so on a cold start. Otherwise the the warm running current should be bouncing around 5-10 ma. You may have a vacuum leak somewhere. Check for leaks with starting fluid sprayed around the fuel injectors or anywhere else there is a vacuum connection.

[JRKman]

sprayed all around all the connections I could find. Nothing. But it was warm and has no problems at operating temp. I'll spray again tomorrow morning. One thing I did notice is where the injectors connect to the head, they are all clean and dry besides the one closest to the belts. That one is a little bit cruddy... Could this be the cause of my problems? Maybe when cold there is a leak there and when warm is seals itself.

-Josh

P.S. Thanks elements for taking the time to provide input. I appreciate it.

[elementsoffury]

It's probably cruddy because oil gets spilled there when filling the engine.

Try to confirm the after-start enrichment is within spec

[JRKman]

Went out and unplugged coolant temp sensor, hooked up the meter to the 200mA scale.

1) Cold running enrichment without turning starter: 82.5mA


2) Grounded the coil wire and turned over the starter for a couple seconds then left the ignition on. Meter showed 143mA for about 25 seconds then started dropping. By 40 seconds it was at 100mA and at 50 or so seconds it was holding 83mA.

[JRKman]

Coolant temp sensor PLUGGED IN, hooked up the meter to the 200mA scale. The engine/coolant is already heated up.

1) Ignition on without turning starter: 14mA then within 3 seconds down to 8.8mA


2) Grounded the coil wire and turned over the starter for a couple seconds then left the ignition on. Meter showed 14mA then within 3 seconds dropped to 8.8mA then after a few seconds up to 18.8mA and holds there.

[elementsoffury]

Sounds proper. But confirm with the bentley manual.

Seems like you're stuck at the same point as me. Engine runs healthy all around, just cold starts suck. Mine starts fine when it's still pretty warm.

Hopefully someone who knows what they're talking about chimes in.

[JRKman]

The values taken with the coolant temp sensor unplugged match the values in the bentley. I do not know about the values with the cts plugged in. Everything seems to check out so idk why the damn thing does this when its cold.

[elementsoffury]

I'm starting to think it has lots to do with that potentiometer I mentioned earlier. I remember someone who sounded knowledgeable recently posting on here, talking about cleaning the wiper it uses. It was about cis-e Motronic but they're both pretty much the same potentiometer....Only thing is; when you try to tinker with it, you have to deal with adjusting it as I mentioned.

[JRKman]

Here is something about that I found in the bentley. I went through the resistance tests and this is what I got.

http://www.race.nangreaves.com/golf/FU01/ch6.4.2.html

Pin 1&2: 5000 ohms
Pin 2&3: 850 ohms
Pin 2&3 with plate at highest position: 5600 ohms (says it should be 4000)

-Josh

[vweater2001]

Try cleaning the ICV and also the Idle control screw that worked for me.

[elementsoffury]

Nice. It has been a long time since I've tinkered with it, so as you can see, a lot of details are fuzzy in my head. Good to know you don't need to have that special plate holder tool, just a steady hand.

I guess next step would be to remove that thing altogether, and try to clean the tracks it contacts. I'm pretty sure I did this and it was spotless to begin with. Either way I was able to wing the adjustments back in spec with the voltage test. I only have a $30 meter so I don't know if would be considered accurate enough and my harness rigging wasn't the best.

Please post up if you get this figured out.

Good luck!

[JRKman]

Try cleaning the ICV and also the Idle control screw that worked for me.

Thanks for the tip. Unfortunately thats been done already

[JRKman]

I guess next step would be to remove that thing altogether, and try to clean the tracks it contacts.

I have 3 complete assemblies with the fuel distributor, DPR, and the potentiometer. I completely swapped to the 2nd one a few months ago and it didnt get rid of the problem. I went out to the shed to grab them and measure the resistances at the potentiometer and they all came to about the same values.

pin 1&2: 5300 and 4800 ohms
pin 2&3: 850 and 900 ohms
pin 2&3 with plate at highest position: 5600 and 4800 (biggest difference here)

I have to fix this haha its my ladies car and I never hear the end of it. If only it was as simple as my 69 bug.

[JRKman]

The only thing that makes me question that it is the potentiometer is because the screws are sealed with a rubbery sealer. And the bentley specifically says NOT to adjust it unless replacing it.

[JRKman]

So I went out and measured the voltage between pin 2 of the potentiometer and ground with the ignition on and the air flow sensor plate held in the proper location with my hand and it fell within spec of the bentley :/

NOW WHAT??

[elementsoffury]

Wait, how long does it take from a cold start to run normal? If it's more than like 2 minutes try richening the mixture. You're already out of spec, so try to going within specs.

The car is in closed loop until coolant temp reaches like 140 or 160f.

[JRKman]

It'll take 5-10 minutes for it to go away depending on if I let it idle in the driveway (5 minutes) or if I drive off (10 minutes).

To richen the mixture I have to drill the plug on the fuel distributor and turn the screw underneath clockwise with the 3mm allen wrench correct?
-Josh

[JRKman]

try richening the mixture. You're already out of spec, so try to going within specs.

I swapped the complete fuel distributor out to one that had the hole already drilled. I also took the for sure working dpr from the distributor I had on it before and put it on the new distributor. I then checked the cold enrichment/after-start enrichment after I was done installing. That was good to go.

Started the car (suprisingly didnt misbehave like normal) and warmed it up with the dpr current displaying. Once the fan cycled on and off I set it to 9mA average. Before it was about 13-14mA average. We will see what happens. I'll keep you updated.

-Josh

[elementsoffury]

Nice. Sorry for directing you around the moon, just to go next door I forgot to ask you about the time right off the bat.

You can just pull that plug out with some pliers.

My car definitely cold starts better than yours, I probably can get it to start and go perfect, but I keep forgetting I have it set to run pretty lean and a very low idle to save gas.

[JRKman]

I'm just hoping that's all it is.. A silly 5mA of current

[JRKman]

Well out of 4 starts this morning, the problem has seemed to disappear. Thanks for all the help.