vdoggie

91 Z with a 5.7 and it infrequently stalls.. appears to do it at low idle coming to a stop, at a stop, or backing up not really touching the gas pedal.. I need to start with the simple things to check.. not looking to replace anything until I have exhausted all my resources on at least the basics.. also have noticed potential gas smell after it dies and start it again.. it has no problem starting back up and driving.. no hesitations etc.. only other thing to note is a slight rough idle.. something doesn't seem dialed in all the way.. could timing have an effect on all of this?

thank you

Ron U.S.M.C.

Yes timing could be playing a roll. Do you have a timing gun? If not you should be able to borrow one from your local auto parts store. Try to get one that also reads RPMs that way you will know if it is correct or not. There Is a procedure used when checking the timing so if you don't know it just ask.

The Idle air control valve may need to be eather cleand or replaced. This brand is one of the top of the line soled at Napa Auto. You can get them cheaper at O'Reillys /etc.=
http://www.napaonline.com/Catalog/Ca...773_0169841328
or
http://www.oreillyauto.com/site/c/de...+control+valve

Also you can adjust the idle a tiny bit by adjusting the throttle position stop screw. You only turn the screw tiny bit too just barely raise the idle. Remember how far you have turned it in order to set it back where it was if necessary. It uses a Torx style (star shaped) driver. Only use one that has a long enough handle not a bit that fits on the end of a driver because you could get it stuck inside having it pull off of the driver. Do the timing check first.

vdoggie

ron,

ok, gotcha.. so check timing, then check iac valve and or clean it. how to tell if need to be replaced?

if timing and iac valve are good/clean/replaced with a new one.. it's either going to be running better with no stalls or still off a bit and I can then adjust the idle by using the torx on the throttle position stop screw (where the heck is that? lol)

Thanks.. and your paint job still rocks!!

Ron U.S.M.C.

In my Chilton’s book it says you should be idling at 600rpm in closed loop/operating temperature .Very important. That means you will need a timing gun with RPM feature.(you can’t trust the stock tachometer) besides you really need a digital reading because its easer to see the exact reading. At that point I would compare the stock setting on the balancer to the RPM.s and make small adjustments if necessary to bring you to the stock setting using the distributer/base timing.(make a note as to the starting point of the position of the line on the balancer in case you want to turn it back) Yes the adjustment of the throttle stop screw should be a last resort.

OK, might I suggest at least a Chilton’s repair manual or even better a GM manual for your car. There’s just too much information illustrated/pictures to describe and show many of the procedures.

Also simply go to USER CP
then
EDIT YOUR DETAILS
then fill in the last 4 lines at the bottom of the page.
Car =
Engine =
Transmission =
Axle/Gears =

It will appear under your user name and will help us as the thread continues.

If anyone has suggestions or corrections please reply.

eseibel67

You cannot adjust the idle speed with the set screw. The computer will try to get it to 600 RPM no matter where the screw is. The only way the screw will allow any adjustment is if the IAC counts are already down to 0, in which case something else is wrong.

vdoggie

ok, I will concentrate on the other procedures needed to be performed and tested. thanks for the heads up!