Throttle body Questions... 2.0 16v

[spasticone]

Ok.. this is a continuation of a previous thread. I'm finally getting somewhere on a stalling problem that I have with my 92 passat. When coming to a stop and engaging the clutch, it would fall past idle and shut off. It runs flawlessly other than this.

After a rather extensive tune-up and fixing any vacuum leaks I moved on to anything I could find...

All I could do was bump the idle up a tad. It was idling at 850 and I bumped it up to 1100 or so. Then it ran like a top. NO stalling! After a bit more research I found the micro switch at the Idle side was not making contact (because of my idle adjustment). I readjusted it to "click" when it went to idle. The idle went down to 900, and the stalling returned.

What does that switch do?!?!?!? I know that has to be the culprit, but I don't know what to do to fix it. The switch works fine (clicks every time
and has continuity when compressed). Please help me out. Thanks!

[boschmann]

If you've moved the screw with nut that sets the stop point for the butterfly flap in the throttle body then you have problems. That is not to be touched and is not for setting idle. The switch is very important for idle, it's a basic make or break switch that needs to switch when the throttle is fully closed.

[spasticone]

The proper Adjustment for the screw is to turn it in untill it touches, and then exactly 1/4 turn. All it does is keeps the butterflies from getting tight when closed. I can reset at the factory spot with no problem. What does the switch activate??? It has to be a solenoid or something. That's the part I need to find. When it goes to idle, the switch clicks and it dies out.

I have also found very good info on calibrationg the O2 with the injection. This may be my problem. I'll post more as I find it..

[boschmann]

It can be more difficult than it seems to get that screw reset to where the car runs properly. The switch has two parts to it. One is for idle and the other is for WOT. You need for it to make/break the connection for each position. It signals the ECM of what these throttle positions, thus is very important. Have you looked at/cleaned the idle stabilizer valve?

[spasticone]

I have cleaned the isv with carb cleaner.. I don't know much about how it works though. I've also been looking at a few more threads on calibtaring fuel and o2 outputs. The Isv kind of sounds like a good possibility though because of the intermitance of the stalling. I may have to try and get to the u-pull-it and pick one up. I'm trying to finish an investment property, build a house, and move all at once so car fixing is a bit slow going.lol. Thanks for the advice!!! I'll try it out. Have you heard/do you know about adjusting the computer for o2 outputs?

[boschmann]

I'm not sure if we're talking the same thing, but I have seen instructions on how to set the CO or mixture at idle (using the screw in the air flow meter arm sealed below a plug beside the fuel distributor). It is extremely involved and requires a VAG or simulator and a special harness that connects to the differential pressure regulator. I don't know of many people (even dealers) that set it that way. Most just use a CO machine & set it to between 0.2% & 1.2% without watching the diff. pres. regulator amperage.

[91 Passat 16v]

I have a 91 Passat 16v with the exact problem. The car even stalls sometimes when you are on the highway and push in the clutch. Just sometimes and sometimes it works fine. I am looking into a fuel problem maybe a filter.

[spasticone]

I've re-adjusted everything, and i've noticed it ony stalls when it's cold. when it's hot, it's not often that it stalls.