3.2 wants to stall off throttle

[TroyGT]

Hey, after re-installing my engine and getting the car back on the road... I've noticed that it has a tendency to stall when coming to a stop. It doesn't always stall... I can just tap the throttle a little as I'm coming to a stop and all is well. It idles exactly where it always did and runs strong everywhere else. Any ideas on where to look for this? Could it be a vacuum?

-Troy

[flatsixjunky]

Thanks for your post Troy. I recently purchase a 3.2 and it has done exactly what you just described in a few occasions, I'm eager to hear responses for this problem.

[old man neri]

Is that little idle micro switch being engaged? Is the ICV clean? These are the simple things I would look at first.

[burgermeister]

+1 old man neri
Also check your idle speed (add a jumper between the 2 pins in the engine compartment fuse box - Bentley et al show exactly where). Just a small adjustment to mine made the idle quite a bit more stable.

[TroyGT]

That's what I was looking for... I'll give these items a check and re-post findings for flatsixjunky.

Thanks guys!

-Troy

[flatsixjunky]

Hello Troy,

Have you found the guilty party? When you do, please let me know what did you found out.

[Steve W]

Base idle mixture may be too rich, especially after a rebuild that fixed air leaks. Adjust idle CO to .6-.8% with O2 sensor disconnected.

Base idle speed may also be too low, again after fixing intake air leaks. Adjust per factory procedure.

Also, idle microswitch may not be activating, in which case check and fix if needed.

[TroyGT]

You guys hit it right off! It was the microswitch not engaging properly. When re-installing the engine, I adjusted the throttle linkage a little too tight (not enough slack) and that caused just enough tension to prevent the drag arm from resting completely on the microswitch button. Quick continuity tests are the quickest way to diagnose both this and the full throttle switch. I had no continuity on the two prong plug while in idle position... then physically checking there was not 'click' when rolling the throttle off of idle. I loosened up the long throttle wire/arm at the throttle plate by unscrewing it a few turns.. thus making the wire longer and creating some slack between the throttle plate and the throttle arm under the car at the tranny. I drove it to work today and not a single stall.

Thanks everyone for your help.

-Troy

[TroyGT]

Okay... back again. It didn't stall, but it dipped low enough (sub 400) to cause the alt light to blink for a sec. Today, it was cold and raining... had wipers on, radio on, and heat. I've read that the ICV takes over when the microswitch says idle position is reached and then compensates the idle based on draw from accessories like a/c, etc. If this is the case, then my ICV may need to be removed and cleaned... or replaced. Again, no stall... but every time I push the clutch in now it dips close to 400 and then recovers. Today with everything on, it seemed to dip down a little close to stalling. And votes for the ICV on this?

Thanks.

-Troy

[Steve W]

Now that you've fixed the microswitch, you'll have to verify and properly adjust the base idle mixture and speed.

As for the ICV, absolutely clean it out and make sure it rotate freely before anything else.

My guess here is that that the base idle speed needs to be turned up. If that doesn't do it, you'll need to check and adjust the base idle mixture, then go back to the base idle speed.

[DRACO A5OG]

Just a thought, thanks to Steve Wong.

When you come to a stop, how low do you go on the RPM's before you engage the clutch?

I use to wait till that last minute maybe 1200 RPMs before I engage and would occasionally get a sub dip and or stall.

If I engage above 2K RPMs, it will settle down to proper RPMs and never sub dips or stall.

+1 on cleanging the ICV, it will definitely help.

[TroyGT]

As suggested... set my base idle which was off a bit and cracked open the ICV for inspection/cleaning. It appeared to be functioning correctly, however, I cracked it open anyway and buffed it up a bit with the dremel and that seemed to do the trick... at least so far. It had a rusty spot on the inside magnetic? based, where all of the coiled copper is attached. The Ohm readings for the pins were close, 42 on one reading and 22 on the other. Should have been 40 and 20 per the Bentley. Seems to be good for now... will report back after 5 days of commuting.

Thanks for the suggestions.

-Troy