740 engine stalling

hi, can anyone help,my 91 740 wagon,start and run pretty well, but stall and
loses power and sometimes the engine just cut out, at all different speeds.
after I pull over. it starts right up after a couple of second. the service
engine light come on when I first start out and then goes out. Has anyone
run across this problem before thanks gary v.

 

That sounds exactly like the problem I was just having with my '87 which
turned out to be the engine wiring harness, but your '91 is new enough
that it would have the updated harness. Still might be worth looking at
it to make sure a rat didn't chew on it or something.

 

Check the pipe on the auxiliary air valve - it's right on the top of the
engine and also has an electrical connection. The pipe has a habit of
working loose and causing the intermittent problem you describe as it can
re-seat itself enough to work again when the engine stops.

Si

 

I had a 1985 740 that exhibited the same symptoms, after it was 12 years
old. My problem was an intermittent and faulty "hall sensor", inside the
distributor, where the external wiring is connected. The other
suggestions are possible, but I'd put my money on the distributor sensor.
Tell the garage to start with the replacement of the hall sensor, otherwise
they may start replacing the MAP sensor, injectors, fuel pump and heaven
forbid the ECU computer. You may end up with a huge repair bill and no
better off - I've heard of this happening.

Good luck and let us know what is the final culprit.

Cheers.... Cam

 

It sounds like an electrical problem, if the loss of power and engine
stall is intermittent.

If it has low power all the time, rough idle, or your gas mileage is
poor (feels like the engine is not firing correctly) I would recommend
a full tune-up on the ignition system, and plugs. You might check the
plugs, and think about when the distributor cap and rotor were last
replaced.