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