Fassi

When the engine is cold, my 3.2 will invariably perform a start up "routine." It starts normally, idles for a couple seconds at 950, then the engine speed will increase to about 1200, where it will hang for about 30 seconds to a minute, before gradually decreasing and eventually stabilizing at 950. If you tap the gas pedal a bit it speeds up the process considerably. If you try to drive off before the idle stabilizes, the car will hesitate and jerk somewhat for a bit at low rpms until you rev it up a couple times. However, if you wait the minute or two until the idle is stable, you can drive off normally and cruise around a parking garage with no problem. Either way, once on the road, the idle speed does not fluctuate at all. And if the engine is even a bit warm, the engine will not go through this process. Does anyone have any idea what may be causing this strange ritual? Thanks in advance.

r22tek

That is happening by design. It's like a "choke" controlled by the computer. Perfectly normal-no worries.

quicksilver

I wouldn't consider this 'normal' for a Motronic 3.2 but I don't know if I would worry about it. I have an 87 and the idle doesn't ever go as high as 1200 and it never stumbles when cold.
One detail; I live in Southern California so when I say "cold" I mean that the engine is at air temperature. If you mean cold - like "Where is my jacket" than I'm not sure.
It is pretty hard to get the Motronic unit to do anything wrong. One of the most common things that can be a problem is the cylinder head temp sensor. I also wonder if your injectors might be a little dirty. A little heat goes a long way towards atomizing the gas.
If it was my car I probably wouldn't worry about it unless I was looking for something to play with. Besides, we never let any car engine warm up enough before we put a load on it.

If you want to try the cylinder head temp sensor...
It is a pretty easy part to swap except you need a special socket. Don't go buy the socket. Just go get a 14mm deep socket and a cheap 1/4" wide grinding wheel for an electric drill. Then cut a slot up the whole side of the socket so the wire can hang out.
The correct replacement unit is a newer part that has superceded the original. It has 2 wires instead of one but you don't need to worry about the extra. It is just a ground wire and the sensor is already grounded to the motor.

Fassi

Thanks for the advice. I've already replaced the cylinder head temp sensor, but I'll try cleaning up the injectors with an additive.