Car stalls at stop

[32york]

Hi, I'm hoping for some advice on fixing this stalling problem. Some background: this was an automatic tranny car which I got last year and my son and I switched it over to manual. Its been great, shifts fine, plenty of power, a real joy to drive. The idle speed has always been high (1200 rpms) which isn't a crisis but kind of annoying since everything else works fine. So this weekend I decided to take a look and found that the tang on the throttle linkage which is controlled by the dashpot had been bent to prevent the idle speed from dropping to its proper setting. OK fine, so we bent the tang back so the idle now drops down to around 750 rpms. However now the car dies when you pull up to a stop. So apparently a prior owner might have bent the tang to solve the stalling problem but I'd like to figure out what's actually happening here. Do you think that its a dashpot/check valve problem that the idle might be dropping too fast at stop so the car stalls? A dirty throttle body? Any suggestions would be appreciated. Thanks.

 

[bogeygolferkyle]

Hello,

Sorry to hear of your issue. According to the manual (1993), stalling at idle when warm has several possible causes: barometric pressure sensor, idle control valve, exhaust gas recirculation or "other idle controls" I think this includes dashpot controls. I did see in the dashpot circuit there is also a check valve.

You state the car will idle at 750 rpm but that it dies "as you pull up to a stop". This sounds dynamic to me, which is in line with dashpot issues. Sounds like a place to start - keep in mind I'm no expert. The value of my advice is the same as I am charging!

Good luck!


Kyle

 

[jwmelvin]

This is a 91-94 vehicle I take it (didn't DBW start with OBD2)? There is a different idle control for those, involving the idle-air control valve if I remember correctly. Look up the procedure for diagnosing it in the service manual. For the later cars, I would say make sure you clean the throttle body; not sure that has the same implications in the earlier cars. But it may be worth trying regardless.

 

[32york]

Thanks guys, will take a look tomorrow.

 

[dablackgoku1234]

I would check the air filter to see if it is clean. Then I would use seafoam/wd40 and a towel to wipe the inside of the throttle body (including all crevices/senors)

 

[docjohn]

......don't stop....:smile:

 

[Larry Bastanza]

It is important that the idle passage is cleaned. First thing to look at is with the car idling, blip the throttle, if the rpm dips below 750, or even stalls, you need to clear the idle passage in the throttle body.

HTH,
LarryB

 

[32york]

It is important that the idle passage is cleaned. First thing to look at is with the car idling, blip the throttle, if the rpm dips below 750, or even stalls, you need to clear the idle passage in the throttle body.

HTH,
LarryB

Larry, I'm not sure where that passage is, I didn't see it in the service manual. Could you explain a little about how to get at it. Thanks

 

[dablackgoku1234]

That hole beside the throttle plate.

 

[Larry Bastanza]

Just keep in mind the throttle body in the pic is a 1995+ and the OP has a 1991, they are different...

Regards,
LarryB

 

[32york]

Well, I cleaned the throttle body as best I could and changed the air filter and voila! no stalling. However with the lower idle speed it somehow seems slower off the line??? I'll have to get used to this.