E36 320i revving by itself ?

singhters · #1 (**permalink**) 02-11-2008, 03:02 AM

Well the original fault was the same revving by itself at idle,
changed the tstat fixed the issue, then it started overheating,
changed the heater control valve all back to normal and no longer
overheating and now.

My engine stalls, when it's started, and idle, it bounces
idle for a while and then stalls from 700rpm to 0rpm and then
starts again. what is the problem, with my engine.

Also when it did overheat i didnt let it go into the red but I found
that when i removed the coolant temp sensor no water came out and
it seemed to have a black like burn mark on it so i sanded it down
and cleaned it, If i disconnect the airflow meter it idles fine
which means to me it maybe the air flow meter but surely it cant be
because i changed it for a new one only 2 years ago.

What ive done

Ive cleaned the throttle body which seemed to have an awful lot of
oil on it so its possible that the airflow meter is contaminated
as well.

Ive cleaned the icv and changed it.

Ive checked for air leaks and found none.

There is a cut in the throttle boot to the throttle body but its
not gone through.

I have noticed marks on the breather hose like scratches some deep
but again not gone through.

bmw e36 320i euro model 1992

Manolito · #2 (**permalink**) 02-11-2008, 06:32 AM

Normally, when a car idles better when the MAF is unplugged, the diagnosis is MAF. However, due to the history on this car, I am not so sure.

Does the car seem to have normal power off idle?

You can try spraying carb cleaner thorough the MAF to see if it makes any difference. It shouldn't, but it can't hurt.

Your MAF is the model that has the thermometer inside the MAF, right? Search the archive and see if you can find the pins for the thermometer and the resistance reading that it should have. I think that I looked that up for someone once.

singhters · #3 (**permalink**) 02-11-2008, 07:27 AM

my suspicion is growing that it is the maf, because if i leave it idleing without it, its fine but soon as i plug it in while the car is on it goes crazy and after a few bounces it stalls.

but as i sed i found a lot of oil on the outside of the throttle body so it may be gunked up as well.

will try cleaning it.

Manolito · #4 (**permalink**) 02-11-2008, 08:39 PM

I know it is tempting to plug and unplug things with the car running, because you get immediate feedback from the car on the effect of unplugging it BUT, it is a bad idea to plug things in while the car is running, and a worse idea to unplug things while the car is running. It can send voltage spikes through the sensors and the computer that can harm them.