2005 525i Fuel Pressure Problem? (stalls on cold starts!)
I'm looking for help with a problem that neither the dealer nor my repair shop can diagnose.
My 2005 525i sport (58k miles, out of warranty) stalls or won't start when cold starting... sometimes.
When I turn the key on a cold (more than 20 minutes since it last ran) start, one of three things happens:
1. It starts, but at low-ish RPM and stalls out quickly
2. The starter cranks away but it does not start
3. It starts!
If it actually starts, it stays running and purrs like a kitten. The computer reports no problems anywhere. My current mechanic indicates that the problem occurs when the vehicle is in a cold/damp condition, but the problem started when I was living in Florida in August which is not cold (though it is humid). I only use 93 octane Chevron/BP. I've run through multiple tanks of gas since the problem started.
I've had the crank sensor, the fuel pump, and the fuel filter (as well as the Schrader valve on the top of the engine) replaced, and the problem persists.
It *appears* that the vehicle is losing fuel pressure when not running and that may be contributing to the issue. Once I watched the pressure drop from 3.5 bars to 1.X bars in about 30 seconds once while a mechanic tried to start the vehicle. It does not appear to lose fuel pressure once running.
So, I'll ask a few questions and then hope someone knows what is going on:
1. Do e60s maintain 3.5 bars of fuel pressure constantly? Or is it normal for the pressure to drop when the vehicle is off.
2. When BMW NA and the dealer both won't help financially because the vehicle is out of warranty, am I truly just SOL?
3. Has anyone else seen this happening or know what is causing this? I've read the other threads about bad fuel pumps and such but that doesn't seem to be my problem.
Lots of thanks in advance.