Bmw starts then stalls

please help me rescue my 2002 BMW 325i from the Sonic. It starts then stalls. It stalled in the middle of the road the other day while I was going REAL slow. Now it’s totally unreliable. If it starts it leaves me stranded. Turn over just fine never engages.

Check engine light on? What is a Sonic? I would have a shop check for fuel and spark (unless you can do that yourself).

Your post is contradictory. You say “It starts then stalls”, then you say it “turns over just fine never engages”. Which one is it?

Can you hear the fuel pump spin up when you turn the key to the Run position before cranking the engine?

My wife’s 330i left her stranded in front of the grocery store last year because the fuel pump failed. We had warning though, we had been hearing a buzzing sound around the rear of the car for months, so when she called and said her car would crank but not start, I figured that was the problem.

Your description indicates that the engine sometimes fires while cranking but then stops firing when you stop cranking. If so, that indicates a problem with the relay that supplies the fuel pump. Specifically, with the signal that the relay needs from the engine control module that tells it that there are no problems and it is OK to activate the fuel pump. I have seen a few posts on BMW forums with problems in this area on 3-series. Unfortunately, no one posts the solution after they get it fixed. Hopefully the control modules are not failing. That happens sometimes on old Volvos, resulting in this symptom, and those modules are not cheap. For Volvos, folks replace the transistor that fails and sell the ‘rebuilt’ control modules on eBay for about $150.

Sonic is a drive in burger joint. :slight_smile: You are correct, poor choice of words. It never starts, just turns over. It began about a week ago (not starting sometimes). If it starts it usuals runs just fine. No check engine light but a radiator light on and off. The radiator is full. Heater works OK not great.

I thought about that and tried to listen, but heard nothing. Is there a way to check on this?

If there’s a way to supply 12 volts directly to the fuel pump, and the car then runs fine, then you can rule the module as the culprit that way.


“Heater works OK not great”–could be a thermostat problem. May explain the radiator light being on, but it is unrelated to the problem of not starting. Thermostat is normally a very easy repair and cheap part, but I don’t personally work on BMW’s and have heard that parts and repairs can be expensive.

Since the check engine light is not on, my guess is a fuel pump or similar problem that is not allowing fuel to get to the engine. I am assuming that if it were the ignition system a check engine light would be on.
However this is only a guess–take it to a trusted mechanic and have them check for fuel and spark.

You have a radiator light on, but have you had someone look at the system?
There might be an air pocket in the cooling system, which would explain the light, and the less than stellar heater performance.