where's my hall sensor (85 760 turbo)

turbo no/go · Post by **turbo no/go** » 30 Nov 2005, 15:41

i've seen others suggest checking hall sensor when having stalling problems, uh, where's it at?

Guest · Post by **Guest** » 30 Nov 2005, 21:02

In my 88 740 it is in the distributor on the back of the cylinder head. Be careful though the plastic electrical connector is easily broken. When mine went bad it would work until the car got hot. Stop at a few lights or go into a store for a few minutes and it would run very poorly. Let it cool down and it would start right up again. Another symptom was the tach would drop to zero when it was acting up.

turbo go · Post by **turbo go** » 03 Dec 2005, 10:39

thanks for the help. i found where the hall sensor connects into the distributor.i've priced a few just in case, but i'm still not sure that's the culprit. it seems like it's common for a car to either not start, or start and run poorly if tried to start before the hall sensor 'cools down'. mine never starts, or even attempts to(no spitting, surges, exhaust release, no erattic idle/rough running),no running at all.it acts exactly like it is out of gas.engine turning over and sounding like a normal 'crank', it just doesn't start. never any smoke,never any fuel smell,but restarts like it was flooded, that is, it has to sit 1-5 minutes before restarting,and always restarts without fail and sounds/drives completely normal until the next time it happens,which could be 2 hours to 2 days.i'm going to replace my external fuel pump and fuel relay. even though they been tested and appear to be working, i've heard it's a good idea to replace both pumps if they're both original parts. my in tank pump and screens have been replaced, and the external filter.the relay was replaced by previous owner in '95, but that's still 10 years ago.am i right to assume the car would try to start or run rough ocasionally if the hall sensor was causing the problem

Guest · Post by **Guest** » 03 Dec 2005, 12:53

No start can be caused by radio suppression relay near or on coolant tank. It supplies voltage to the injectors. Just one more thing to check. It is the same relay as the one that controls the fan and you can switch them if your coolant relay is working.

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