ISC, Boost leak, Plugs?
 

So i have been searching for days now to try to fix a problem on a car that i just got. Heres the issue.

I can drive the car while it is cold and it is fine with no stalling and really it runs great! but after it warms up, when i come to a stop (Push the clutch in) the cars RPM will drop off to 100-300 RPM or it will just die.

There is nothing done to the car at all. It is completely stock with NO modifications at all. What do you think the problem could be. i have been looking on Vfaq for different ideas on what the problem could be. All i know right now is that it could be a vac leak, ISC, Boost leak, Bad BISS setting. What do you think?

BTW: the Car is a 90 Talon TSI AWD

Re: ISC, Boost leak, Plugs?
 

The 90' ?

Either TPS related or the sensor that the throttle hits on at idle is misadjusted..... Or it could be something else, just throwing in my 2 cents..

Re: ISC, Boost leak, Plugs?
 

^^^ Thank you, All 2 cents will help. So i was looking at that sensor that the throttle hits and it seems fine. I didn't know that i could adjust it though?

What i do to lower the risk of the car stalling is to just downshift to a stop and then leave it in gear until i get to about 1k RPM then i push the clutch in. Then it doesn't stall (Almost everytime.)

If that helps at all

Re: ISC, Boost leak, Plugs?
 

Well that sensor will adjust up and down with a 14 mm wrench. I adjusted mine and it fixed my idle. It was unsteady and it made it steady. The tps will adjust air fuel mixture, but I am not 100 percent sure if it will effect what is happening to you.. You say if it is in gear than it idles at a normal state? Will it die down as soon as you pull it out of gear with the clutch in?


edit**
Also have you attempted adjusting the idle air screw? And have you timed your engine correctly?

Re: ISC, Boost leak, Plugs?
 

If i leave it in gear to come to a stop i can ride it down to about 1000RPM and then i can push the clutch in and it will drop down a little bit, but it won't die... Almost like it has more time to adjust the a/f or something.

Re: ISC, Boost leak, Plugs?
 

Hmm not sure if this will effect it but check the sensor on the trans, it is right on top of the trans and under the BOV... It may be unplugged or it may have corrosion.. As far as a/f i'm not sure if having it in gear would change anything.. however I am new to this..

Re: ISC, Boost leak, Plugs?
 

x2 i just got the car about a month ago and i just started driving it this week. I don't know know a ton about DSM's. i am just lost on why it is doing it. I first thought it was a vac leak, But wouldn't it do it when i first start the car as well.

Re: ISC, Boost leak, Plugs?
 

Have a friend look down the driver's side of the engine at the crank pulley while you push in the clutch. If it moves in and out, you have crankwalk. Just pushing in the clutch doesn't put enough load on the engine to make it die otherwise. And the sensor on top of the tranny is the reverse light, it doesn't have anything to do with your problem. Report back to us once you've checked this.

Re: ISC, Boost leak, Plugs?
 

Will do... Thanks. Lets hope it isn't though

Re: ISC, Boost leak, Plugs?
 

So crankwalk is out of the question... Looks fine.

Re: ISC, Boost leak, Plugs?
 

I would say you need to set your base timing and idle rpm, then check for boost leaks.

~John

Re: ISC, Boost leak, Plugs?
 

dee dee deee

Re: ISC, Boost leak, Plugs?
 

yea i need to check for boost leaks for sure. but would it be the base idle if it is only after i am in a high RPM? Say i am at 3k and i take it out of gear and the RPM's drop to to almost nothing or it just dies..

Re: ISC, Boost leak, Plugs?
 

Did the Biss setting and that definitely helped... So i thought. Everything was great until i went and actually drove the car for a while. the idle is wonderful now. but when i am driving and i have to come to a stop the RPM's still drop off and usually the car dies... but if i just keep it in gear till about 1k and then push the clutch in, all is well.

Re: ISC, Boost leak, Plugs?
 

My car stumbles/dies when stopping. Is there a fix?

This is a symptom of a broken speed switch, which is a part of the speedometer in the instrument cluster assembly. With the switch inactive, the ECU does not know the car is moving and doesn't keep the idle high enough to operate the power brakes. For details on why this switch is important, read this post, where Todd Day (the 'talon mgr') explains it, and this one where he explains how to diagnose it. Search the archives for more information.

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this is taken from Vfaq. Every symptom for it matchs the one that i have. what do you guys think? and how hard is iit replace?

Re: ISC, Boost leak, Plugs?
 

Do you have a pocket logger? I would use that to check your isc. You can tell if your isc is working by looking at the steps displayed by the pocket logger.

Im not saying that it is the ISC, but it is worth looking into it.

And you also make it sound as if the bov is vented into the atmosphere.
You're describing it just like how a vented bov would do to a car, but then you also stated that your car is all stock. Definitly check for any boost looks, and check your BOV recirculation fitting. Also check your base timing, and base idle properly.

Also, and to just keep in mind, some 3/s have problems with their ECU capacitors that would somewhat cause this kind of symptom, and this involves replacing the ECU itself, or replace the capacitors.

I would also try swapping parts in and out to see if that is the problem.

Re: ISC, Boost leak, Plugs?
 

Taking off the gauge cluster isnt hard. Probably 30 minutes top. All you really have to do is take off a few screws and you';ll be able to take out the whole thing.

Re: ISC, Boost leak, Plugs?
 

Did you do a tune-up when you got the car? Replacing everything you need to?

As what on tuner says, these cars are very old, and most likely the person that had it before you, didnt take good care of the car, or atleast assume that he didnt.

I'd really highly recommend that you atleast do boost leak test.

Re: ISC, Boost leak, Plugs?
 

After the base timing/idle set if thats not it look into the speed switch and ICS motor as mentioned above.

~John

Re: ISC, Boost leak, Plugs?
 

^^ Yes i set the base idle... From what i have been reading the Speed switch can for sure cause this problem that i am having. I also am looking into the ICS. Although i don't have a pocket logger like stated above.