530i will start, won't stay running. Engine popping

[530i85DodgeGirl]

Title says it all. My 94 530i has had me working on her as a slow restore. I was starting up and running her every other day to keep the battery charged. Then I had some health problems hit me back in March. March was the last time I let her run for a min. I go to get the final stuff done on her last night. When I turned the key, she cranks just fine. Started up fine, but she dies immediately unless I keep the accelerator pressed lightly. Now her engine is making popping sounds too which had white smoke or steam pop up somewhere from the motor. Is this a vacuum leak? A bad fuel pump? Timing off? What am I dealing with here guys? Every time I try to get my baby back up and going. Something else happens. The parts I've got into her so far are a new water pump, thermostat, tensioner spring and a water pump pulley.

[bmwdirtracer]

Welcome to the forum, DodgeGirl.

We don't have enough information for a diagnosis, but if I had to guess, you've got a fuel/air mixture problem. This could be a problem with fuel delivery, or a problem with un-metered air. (The M60 engine leaks everything everywhere, especially air).

In the end result, you're very likely going to need a few pro-level tools to deal with this, but let's try a simple experiment first: Unplug the MAF (Mass AirFlow sensor), and then try to start the car. When it refuses, and then dies, try again.

So that you know, this "test" is forcing the computer to try to start the car with zero information on how much air is coming in. On a '94 era BMW, this doesn't always work....but it might....and it's free and easy.

IF the car starts and tries to idle, even poorly, it's likely you have a major intake / crankcase vent system leak. If this makes no difference at all, then either the test failed, or you're not getting the correct fuel pressure....
OR
my hunch was just plain wrong anyway. Wouldn't be the first time.....

[MarcoZandrini]

To add to what Chris has written, you need to have the intake undergo a smoke test.