However I made some interesting observations. The stalling only oncurs when coasting before a stop. The idling recovers after a complete stop. Also, the stalling does not occur in N. May this indicate a problem with the hall speed sensor? The idling system will not engage above 1.4 km/h and it is informed about speed by the hall speed sensor. It may me misinformed and think the car runs faster than 1.4 km/h. Does this sound plausible?
Thanks for your comments! Have a good day, Bruno

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1992 300TE 160 kmiles

Idle control valve is sticking and/or the idle control valve hoses leak badly.

Stalls on coast (especially if braking hard and stopping abruptly) are diagnostic for a sticking idle control valve.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Thanks Peter
Well, I cleanded the ICV and replaced both its vacumm hoses. Maybe I'll check again.
Bruno

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1992 300TE 160 kmiles

Bruno:

Sometimes the ICV is worn to the point cleaning won't fix it, alas (they aren't cheap!). I ran through nearly a whole can of carb cleaner before it came out clear on mine, they can hold an amazing amout of old fuel dye residue and dirt.

If stalling occurs at ANY time other than sharp braking coming to a stop, replace the fuel pump relay! This will cure other idle problems as well, fixed the TE's rough loping idle, believe it or not. Must have something to do with pressure control.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Ok, I recleaned the ICV though there was not much dirt left, and the condition persisted. I then replaced the Hall effect sensor, still it would stall occasionally. It was exclusively when coming to a stop so I ruled out the fuel pump relais (=MAS unit in case of my car). I then bought a used ICV off ebay for 30$. The stalling never ever came back since I swapped ICV's (4 weeks, about 1000 miles). Sometimes idle speed is too low (500 RPM) especially with a hot engine, but this does not bother me too much as long as the car does not stall anymore. So thanks for insisting, Peter.
Bruno

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1992 300TE 160 kmiles

I finally figured out the reason for the low idling: the electrical wire running to the ICV at the connection to the ICV occasionally lost contact. Making the female connecter tighter did help so far. Bruno

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1992 300TE 160 kmiles

That's a darned good diagnonis and a hard one to track down.

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Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.