1985 760 turbo- stalling

[turbo no/go]

it sometimes goes days(rarely) without stalling,usually it does it 1-3 times a day with normal driving(25- 50 miles).no other symptoms are present when it stalls.the tachometer quickly drops to zero,and the engine stalls.it never
starts back immediatly.i wait 2-3 minutes and it always starts back up and runs normal.this has been happening for 2 months,almost every single day it's driven, although it never seems to do it in the morning while it's cold, engine seems to start stronger first time of the day, but rarely ever starts any time on first turn of key,always takes 2.one slightly longer crank first as if it doesn't have fuel,then a quick strong second start.
i've owned it for one year.it has 164,000 miles on it.i have replaced the air mass meter, pressure regulator, intake hose, in-tank fuel pump, fuel filter,air filter-twice, plugs-twice ,wires, as well as had the external fuel pump tested,alternator and battery tested,pump relay tested and 4 shops and $1200. in repair later and iM out of money, patience, and ideas.HELP

[Guest]

three things that I can think of . First change that fuel pump relay it is only 20$ at fpc groton. I think this will make the tach drop

Ignition control module on drivers front fender is a possibility. I bought a used one off of ebay for $20 It didn't help me. This will also make the tach drop to zero

Hall effect pickup in the distributor. This went bad in my 1988 740. Tach instantly drops to zero. Runs bad on restart unless you let it cool down then it would run fine until it go hot. Got progressively worse. Cost $90 for a new bosch one but there was another availble for less at www.fpcgroton.com look for bad connection on back of distributor . Electrical connector is fragile plastic and gets even more fragile with age. I think this is your most likely culprit. I would also sugget the speed sensor but I do not think your car has one. Remember to tell us what you find.

[yminkc]

You have a bad RPM sensor. This is found in the back of your firewall and what happens is the wire gets hot and burns up. It is a somewhat inexpensive repair. The symptoms are you are driving along okay, and the car just quits. You wait 5, 10, 15 minutes, and you can drive again...only to have it stall. That is your problem. Don't waste money on a fuel pump relay. Fuel pump relay is bad if car won't crank over. You turn the key...nothing will happen. If you have bad RPM sensor, the car turns over, but may not start...or will stall after driving. Let me know if this helps. [email protected]