# CIS start/idle issue



## sandrunner (Apr 26, 2003)

I'm having trouble with my wife's '86 vw scirocco. 
Motor is a 1.8 JH with CIS. It's got a frequency valve but no idle stabilizer. What version of CIS is this?
Normally it runs perfect, but within the last few months it's been having an issue. Starting in the morning or afternoon, it idles rough and frequently stalls shortly after startup. After running for a few minutes(poorly), it clears itself out and runs perfectly.
We've check the mixture with a dwell meter, replaced the O2 sensor, checked the cold start valve operation, and checked the operation and resistance of the air bypass valve. We've also replaced all the vacume lines, fuel injector o-rings and adjusted the warm idle and timing to within bently specs.
Any suggestions as to the next item to check?


----------



## TheGreenspanator (Sep 21, 2005)

*Re: CIS start/idle issue (sandrunner)*

Fuel pump relay
believe it
oh also, f- CIS!


----------



## fwdvw (May 12, 2000)

*Re: CIS start/idle issue (sandrunner)*

Here's one of my favotire threads I found at RB publications forum:
http://tech.bentleypublishers....rt=30
Read it and try the diagnotic proceedure and see if you can narrow the problem down. I found out my control box was bad. Replaced it and it ran fine.


----------



## IllIllIll (Jun 29, 2006)

*Re: CIS start/idle issue (sandrunner)*

This sounds similar to the issue I am having with my 88 fox. It stumbles shortly after startup, & acts as if it isn't getting any fuel & then after a few seconds it clears up & runs beautifully. If the engine is still warm it doesn't have any problems. It only happens when the engine has cooled for a couple hours. It doesn't matter weather the engine is idling or if I am driving, it acts the same. It usually happens in the first 2 minutes of starting the car, so I just wait for it to happen before I drive off.

_Modified by IllIllIll at 7:22 PM 5-31-2007_


_Modified by IllIllIll at 7:42 PM 5-31-2007_


----------



## Eeyore99nb (May 31, 2003)

both of you need to check your timing. preferably with an adjustable timing light. to verify where it really is.
my car had a bad idle switch which caused me to set my timing too advanced using a standard timing light.
this messed up my first start of the morning & afternoon. it also caused my mileage to be horrible and at times my car would have a red hot exhaust manifold and be totally gutless.
my timing was off and my mixture was wrong per the DPR.
good luck


----------



## IllIllIll (Jun 29, 2006)

*Re: (Eeyore99nb)*

My timing is good as I checked it after I changed my timing belt. The car acted the same before & after I changed my timing belt. My mileage is still a consistent 30mpg every time I fill up. I replaced the spark plugs wires, cap & rotor, as well as the fuel filter, & air filter all within the past 10000 miles. I changed out all the deteriorating vacuum lines about 3 years ago, but the car sat for 2 years when I lived overseas. I change my oil & filter regularly, & I have tried different gas.


----------



## Longitudinal (Nov 13, 2004)

*Re: (Eeyore99nb)*

Good to see you in here, Aaron!


----------



## sandrunner (Apr 26, 2003)

My wife's timing is correct according to my adjustable timing light. There is no idle switch, only a full throttle enrichment. Now that it's the weekend I'll be replacing the pump relay and looking at replacing the fuel pressure regulator if I can't get her's clean.


----------



## IllIllIll (Jun 29, 2006)

*Re: (Eeyore99nb)*

Sorry Double post.


_Modified by IllIllIll at 8:29 AM 6-2-2007_


----------



## sandrunner (Apr 26, 2003)

*Re: (sandrunner)*

Well....
Replaced the WUR and idle bypass valve with known goods.
It's much better on startup, but still sometimes idles low till it warms up a bit. Had it stall on me 2x today while it was still cold, just backed up then stopped. Idle dropped a bit then stalled out. Started right back up each time but I know it shouldn't be doing that. 
Any suggestions?


----------



## TheGreenspanator (Sep 21, 2005)

*Re: (sandrunner)*

Mine shuts off when time I get hard in it and then get off, and the idle used to really "hunt & peck" - it got better after my fiance discovered the bad thing in the fuel pump relay, and I have to keep the [I guess] idle bypass plugs (those things on the psgr side shock tower area] unplugged when it's warm out but leave them in during the winter, and that helps w/idle & overall running. 
Also You HAVE to let the car warm up before you drive it anywhere, it's not like an new FI car, it's like having a carburated car, can't just jump in and go.


----------



## tolusina (Oct 19, 2004)

*Re: (TheGreenspanator)*

http://dana.ucc.nau.edu/~kaw5/CISidle.htm


----------



## sandrunner (Apr 26, 2003)

*Re: (tolusina)*

I've tried the CO2 adjustment according to the website. Unfortunatly, at 45 degrees the idle tends to "hunt" and spit out the exhaust. If I richen up the mixture a LOT, the idle smooths out. The only problem with this other than mileage is that I've had to disconnect the full throttle enrichment switch or the engine tries to die under load at full throttle.


----------



## tolusina (Oct 19, 2004)

*Re: (sandrunner)*

Read down near the bottom of the page, the section titled
"Basic Oxygen (O²) Sensor Testing:", 
it pretty well covers ECU functions too.


----------



## idmini (Jan 7, 2004)

*Re: CIS start/idle issue (sandrunner)*

I have a similiar car 82 'rocco with 1.7 and i am having the identical problem it started after i replaced the vacuum hoses. I noticed you said the problem cleared up after replacing the WUR, i was just wondering what that is? Any response would be helpfull.


----------



## sandrunner (Apr 26, 2003)

*Re: CIS start/idle issue (idmini)*

Replaced WUR after a good cleaning, replaced the idle bypass after a good cleaning, replaced the idle bypass hose (had a crack) and swapped in a larger TB(I was in there right?). Now she starts perfectly, idles down a little for a minute, then clears right up. I've got mine set a bit overly rich right now as it seems happier that way. Still getting 35mpg and the wife is happy.
The O2 sensor tested perfectly giving an immediate signal when any changes were made. I'll probably replace it anyways since it's only a $25 part. That may fix the stumble right after startup.
Oddly, my 78 rocco with basic CIS runs perfect all the time now that I've adjusted it to run the 2.0.
If you replaced the vacume hoses, I'd check your mixture. Many small leaks could have added up to one large enough to screw with the mixture.


----------



## petebee (Jul 8, 2006)

*Re: CIS start/idle issue (sandrunner)*

Where did you get your replacement vacuum lines? I am having similar problems and I'd like to replace the lines first (old and brittle).


----------



## u4sure (Jul 12, 2007)

*Re: CIS start/idle issue (petebee)*

Sounds like the primer fuel pump inside the tank. VW has a TSB on this and may also have a recall on it.


----------



## Eeyore99nb (May 31, 2003)

*Re: (Longitudinal)*


_Quote, originally posted by *Longitudinal* »_Good to see you in here, Aaron!

Thanks Jonathan, I figure you showed me so much, I might as well share when I can.


----------

