# CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v.



## Caleb (May 19, 1999)

I recently bought a car that I am fixing up and then going to sell. It has a issue that I can't really figure out. The car in question is a '87 Jetta GLI 1.8 8v with a auto transmission








Anyway the problem is that when the car is cold and I start it up it doesn't want to take throttle. It will idle on its own but kind of rough. Idles low and rough but will stay running. Once you apply any throttle it runs worse and wants to die. You can very gradually apply throttle and it will kind of pick up rpm but still doesn't run well. The deal is if you let it get warm either by letting it idle for a while like this or by getting it to run well enough to get it out on the road and drive a few miles it seems to clear up and run pretty decent. Still has a slight misfire at idle and slightly rough idle but not to bad really. Totally driveable once warm and this problem clears up.
Now to make things worse this problem is not consistant. One day it may start up fine and run decent the next it may run rough and not want to take throttle. It doesn't appear to do this once the car has been driven and it up to temp. I have never noticed the car acting up like this after it has warmed up.
I am by no means a CIS-E expert and actually hate the CIS based systems. Can anybody help? I can perform and diagnostic's needed to solve the issue. I can tell you that the PO has replaced the Thermo time switch and both coolant temp sensors in the coolant flange that come off the front of the head. I think one operates the fuel system and the other the temp gauge in the car. All are new.



_Modified by Caleb at 4:27 PM 10-7-2007_


----------



## PASHAT (Oct 23, 2006)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (Caleb)*

Sounds like a vacuum leak....check the injector o rings seals and the intake air boots. Check to ensure the fuel plate is moving smoothly. See my sig for other issues.


----------



## Caleb (May 19, 1999)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (PASHAT)*

While I do think it is a good idea to check for vacuum leaks in general I don't think that is the source of this problem because if it had a vacuum leak of any size (which it would have to be to cause what I am seeing) then that would affect overall performance and runability all the time not just when cold and so randomly. I will check that out though.


----------



## PASHAT (Oct 23, 2006)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (Caleb)*

It is not what you don't know that will get you in real trouble. It is what you know for certain to be untrue, that is not. For example, a hot engine could seal the o rings on injectors better than a cold one one could.
Any vacuum leaks will cause a loss in the ability of the engine to pull the fuel plate up which is needed to provide fuel to the engine in the proper quantities. This would cause the symptoms you are experiencing.
Check the bottom of the air boot and the injector o rings. These are Common vacuum leaks. Also make sure your dipstick is sealed properly.
It could also be your temp sensor and/or your DPR set improperly. Needs to be fluctuating at 10 mA, I believe, with an 8v CIS-E. 


_Modified by PASHAT at 7:25 PM 10-7-2007_


----------



## Caleb (May 19, 1999)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (PASHAT)*

Ok I have checked for vacuum leaks. I found one. I used the method of taking a propane torch with the flame off obviuosly and waving it around the different hoses and connections where a vacuum leak could be. I found one leak. It was at the large boot that connects to the top of the fuel plate. It was a fairly small leak but a leak no less. I checked both visually and with a propane torch all of the other potential areas and all checks out good including the injector O-rings. I have a extra boot and I am going to change it probably later today.
While I was checking for the leaks I started the car obviously. I was stone cold. I had not started it in a couple days. It ran decent. It did not show any of the signs of trouble that I am trying to diagnosis. That confirms my thoughts that the problem is intermident and random. I understand I need to fix the vacuum leak but that is not what is causing my problem or it would have ran poorly when I started it today.
What else should I check? I will check the DPR and report back today as well as with the results of me changing the boot that has a vacuum leak.


----------



## PASHAT (Oct 23, 2006)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (Caleb)*

It also could be a timing issue. Check to make sure your timing is set properly. If it is, it could be a knock sensor, if you have them on your vehicle. A bad reading from a knock sensor could throw the timing off when it shouldn't.
Do a pin test on your ECU.


----------



## Caleb (May 19, 1999)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (PASHAT)*


_Quote, originally posted by *PASHAT* »_It also could be a timing issue. Check to make sure your timing is set properly. If it is, it could be a knock sensor, if you have them on your vehicle. A bad reading from a knock sensor could throw the timing off when it shouldn't.
Do a pin test on your ECU.

I think that is exactly what it is. I was actually talking to my parts guy today while getting a fuel sending unit for my '81 Jetta diesel and I was talking to him about the issue. He said that he would bet that it is something in the knock sensor circuit. He figured that was causing the timing to do screwy things. Well as it turns out I think that is exactly what is going on. 
I took a look under the hood today when I got home this evening and found that the plastic cover type deal around the knock sensor where it bolts to the block was damaged. Cracked in several places and overall very crappy looking. I then looked at the three wires coming off the sensor and one was broken. I then traced the wiring back to where it connects into the main harness and that connector was damaged and the wires all screwed up. I am going to replace the knock sensor and see if that takes care of the issue.
I will report back once I get that fixed. Could be tomorrow if I have a part off another engine laying around or maybe a couple days if I have to order the part.


----------



## labradorous (Oct 5, 2007)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (Caleb)*

has the mixture screw plug been removed yet?if not it may need adjustment mine did when it was doing that.it was the dpr just needed a little more fuel to wake it up.


----------



## Caleb (May 19, 1999)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (labradorous)*


_Quote, originally posted by *labradorous* »_has the mixture screw plug been removed yet?if not it may need adjustment mine did when it was doing that.it was the dpr just needed a little more fuel to wake it up.

I will take a look and see. I don't know.
UPDATE: I put in a new knock sensor. It did nothing to change the problem. I started the car up after installing the new knock sensor and it does exactly the same thing. But now I have two new problems I have not had before. The car feels like it has a misfire when driving down the road. Not constant just occationally. Also the idle surges up and down. Like the ISV is screwed up but it has never done this before.
I hate this car and the stupid CIS-E crap. You can't diag. it worth a crap. Stupid old technology








Anybody have any ideas to try. I looked at the plug wires. They look fairly new. Brand-X but fairly new. The cap and rotor both look ok. Not new but still look OK. I have not pulled the plugs yet to check them out but I am going to probably do that next.


----------



## PASHAT (Oct 23, 2006)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (Caleb)*

No need to despair.....there is still LOTS to check!!















You should get a reading from your DPR. You will have to build a harness as you have to test the DPR current while the DPR is connected. This will give you an indication of whether your temp sensor and 02 sensor are working properly and that your DPR is adjusted properly.
Does your vehicle only have ONE knock sensor?
Have you checked your timing? Have you ensured that the camshaft timing belt has not skipped a tooth?
Did you test the injector o rings (and please don't tell me you checked THOSE with an open flame







) Pull the injectors and check for proper spray pattern, and replace the o rings while you have them out. It is a 10-20 minute job and costs less than 10 bucks... Also check for fuel volume when you have them out (collect for 30 seconds from all injectors....)
Did you carefully check UNDER the intake boot for leaks....again.
Check and clean ALL your grounds and put dialectric grease on them.
Check your fuel pumps.



_Modified by PASHAT at 3:01 PM 10-11-2007_


----------



## Caleb (May 19, 1999)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (PASHAT)*

Yes I agree the DPR is my next step. I hope to get that done very soon.
Yes the car only have one knock sensor. It is a RD engine code that has the Tci-H with knock sensor ignition system.
I have not checked timing. I need to do that as well. I don't have a timing light but I need to get one so I will probably buy one tomorrow.
Yes I tested the injector O-rings. No open flames were involved. Just a unlite propane torch. I will pull the injectors and check them out. If I pull them I am just going to go ahead and throw on O-rings while I am in there.
Yes I pulled all the intake boots off and looked under them as well. No dry rot, no cracks, nothing. They all look good now.
I plan on checking out the grounds tomorrow.
Fuel pumps are all pumping but I will check flow tomorrow as well.


----------



## G-Magoo (Dec 1, 2004)

Here is a suggestion, not sure if its the problem but it is something I have encountered with similar diagnosis issues. Its possible that your Thermo Time Switch is or has gone bad. If the car seems to run "better" once up to temp then its possible the TTS is not engaging the Cold Start Valve upon starting it. I had a similar problem, same diagnosis. The car would run like crap till warm, but it wasnt consistent. Some days it did it and some it didnt. Finally one day it just decided not to "fix" itself once it warmed up. 
Here is what you need to check if it in fact is this problem...
On your water kneck where your thermostat is there should be 2 plugs / sensors. One having a single wire which is for your temp gauge. And 1 containing 2 wires, this is your Thermo Time Switch. Unplug the harness from this sensor and with the car shut off take a piece of wire and make a jumper in the plug. Thus completing the circuit and telling your ECU to shut off the Cold Start Valve. 
Now start your car back up and see if that helps any?


----------



## Caleb (May 19, 1999)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (Caleb)*

I think I have found the problem. Or at least I hope so. I started to do the pin tests for what I guess is call the Oxygen sensor control unit. Or at least that is what they call it in the Bentley manual. Anyway there is a table with a bunch of pin tests that you can perform at the control unit harness. I started on that today. I did not get past step one which was battery voltage between pins 1 and 2 with ignition on. I had no voltage. Turns out I am getting power in on pin 1 but pin two which is ground has very high resistance. Around 15.1 ohms to be exact. I have a crappy ground somewhere it would appear.
I am working on that now and hope to have it fixed tomorrrow. If I get it to the point that the ground is good and I am getting voltage between pins 1 and 2 and I still have a issue I will have to troubleshoot further but I think that may be my problem.


----------



## PASHAT (Oct 23, 2006)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (Caleb)*

You Bentley should have a list of ground locations. There might be one right by the o2 sensor connector, and a ground strap near the distributor.
See my sig....REALLY check your grounds! Good luck!


----------



## Caleb (May 19, 1999)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (PASHAT)*

I wanted to update everybody on what I found. I did have a bad ground. Just behind the harness that plugs into the Oxygen sensor control unit there is a welded splice (I think that is what VW calls it) that has about four wires going into it and one wire coming out. That wire coming out is a brown with red stripe. It was not grounded correctly. Now the downside is I had to rip into the harness to figure this out but it is not fixed. I took about four different ground wires that come out of the harness right around where they go up into the rain tray. I took those wires and soldered them together and then soldered all that onto a large brown ground wire that I ran straight to the battary. Runs great now.


----------



## PASHAT (Oct 23, 2006)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (Caleb)*

Do you love CIS-E now?


----------



## Caleb (May 19, 1999)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (PASHAT)*

Not yet







But I am getting used to it a little more.


----------



## PASHAT (Oct 23, 2006)

*Re: CIS-E car won't take throttle when cold. '87 Jetta GLI 1.8 8v. (Caleb)*

That might be as good as it will get!


----------

