Stalling sometimes at stops?
 

Recently on occasion my 90 zr1 stalls when rolling to a stop. On even rarer occasions it will throttle. On my old 89 bentley it was the idle control valve. Is that what's doing it on my 90? If so where is it located? Tkx jim f

Re: Stalling sometimes at stops?
 

What are you doing in the rolling stop? Meaning are you slowing off brakes and motor? Or clutch in and it is neutral?

Have you put a scanner on it to see what it is doing? Specifically IAC steps and fuel.

Also what PROM is in the car?


I just went through this on my car, someone befor me modified some tables and that caused issues, I but that is one of many things

Re: Stalling sometimes at stops?
 

This happened a bit after Marc did his 510 package on my '95. I stopped by his shop and he made a slight adjustment to (I think) the throttle stop and it was fine after that. My recollection made not be entirely accurate, as it was about 8 or 9 years ago, so I would suggest a call or email to him to see what he recommends. --Bob

Re: Stalling sometimes at stops?
 

Marc probably closed the throttle plates slightly to increase IAC steps.

Re: Stalling sometimes at stops?
 

One of the previous owners had Marc do.many things and it's been fine the last 20k +/- mi. So this is new .it started after the 1st 1k mi I drove it. The only electronic item I did was clean the grounds and codes for the frame sensors.
Again can it possibly be the throttle control valve if I have one? Tkx jim

Re: Stalling sometimes at stops?
 

Entirely possible Dom--I just can't remember exactly what he did. --Bob

Re: Stalling sometimes at stop
 

Well I guess we can ask Marc next week. Closing the throttle plates causes the ECM to increase IAC steps in order to maintain commanded idle speed. This gives the ECM more ?headroom? to control idle speed.

Re: Stalling sometimes at stops?
 

One thing to give a quick check to, is these PCV vacuum blocks common to the '90.....depending on the mileage, they can become oil soaked, and then not seal very well.....they are at the driver's side front of the plenum kind of tucked up in opening a bit......push on them a bit, and if they leak a lot, they should be replaced. They can cause erratic idle due to vacuum leak.


https://imagizer.imageshack.com/v2/1...923/ngtGRK.jpg

Re: Stalling sometimes at stops?
 

Spoke to Hibeck today. Thinks it might be a semi stuck throttle. Just document it if and when it happens.

Re: Stalling sometimes at stops?
 

Had that issue w mine a number of years ago. I have a 63mm TB so no dag. Throttle return springs get weak after 30 years and I gotnone of Marc?s helper springs. Throttle closes correctly ever since.