M10 stalling as soon as it starts when cold?

[Kaz 50]

Hi there,

I've done a lot of research and found lot of dead end threads on this topic but hoping someone can shed a bit of light on my situation.

Long story short, My BMW E30 with a M10B18 engine stalls about a second after it starts when the engine is cold. Doesn't matter how much throttle I'm using, or none at all, it will always stall. I've noticed I can unplug the Air Flow Meter, and the car will run very rough and will die with no throttle, but will enable me to drive it for a short distance, enough to warm up the engine. After a couple minutes of driving without the Air Flow Meter plug attached, I will feel the car loose power. After that happens I plug the Air Flow Meter back in and the car runs perfectly fine, as if nothing ever happened.

My original thought was it must be a broken Air Flow Meter or Sensor. I replaced that, same thing. While replacing that, I noticed a few small cracks in the intake piping coming to the Air Flow Meter so replaced that too. Same thing kept happening. Thought it could be a fuel pump/filter issue. I had a mechanic come around to take a look at it, The old filter was clean (only replaced last year which was only 2-300km's ago), and according to the mechanic, the fuel pump is pumping as it should, and the fuel is clean etc. He then suggested possibly the replacement Air Flow Meter could also be no good. This time I made sure I went to HellBM to get another Air Flow Meter, cleaned that one all up with some AFM cleaner, plugged it all back together and same problem again.

The car in question has around 123,000km's on the clock and has barely been driven the past 5 years we've owned it, however would start and drive perfectly every time up until this started happening a few weeks ago.
 

My question is, anyone have any idea on what could be the problem, and what to check next? Could there be a leak somewhere I can't see that is causing this?

[gjm 3193]

Warm up regulator? 

Pull the electric plug from it and (with engine off) test for open circuit.

With engine running, test for voltage across the same connection - should be 12V, although 11.5 is acceptable.

[aja540i 1896]

Wouldnt hurt to check for vacuum leaks between AFM and head as well.

[Kaz 50]

On 12/08/2016 at 6:14 PM, aja540i said:

Wouldnt hurt to check for vacuum leaks between AFM and head as well.

I replaced that hose and didn't appear to be any leaks but will check it again.

 

On 12/08/2016 at 5:34 PM, gjm said:

Warm up regulator? 

Pull the electric plug from it and (with engine off) test for open circuit.

With engine running, test for voltage across the same connection - should be 12V, although 11.5 is acceptable.

Thanks, will try get my hands on a voltage meter and check it.

[BM WORLD 1258]

try removing the ICV and clean,lube and check it , probably seized up from lack of use and age etc