Re: Diagnosis for stalling? (archive)

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I'd first check those fuel pumps. Your wife running it out of gas is not good. The pumps require fuel as a heat sink and when the tank runs dry the pumps burn up. Checking the pumps will also check the relays to them. Better change the fuel filters. Cheap and easy to do. By running the tank down so far they may have picked up some nasties.

I don't agree with Kevin on the vapor lock issue as the fuel rails have a fuel regulator in each one which dumps fuel back into the fuel cell afte proper fuel rail pressure is achieved. This constant pressure provided by the pumps and fuel return to the cell keeps the fuel lines clear.
Gas smells can come from alot of places. The hoses going to and coming from the fuel rails are prime candidates as well as the fuel pressure regulators themselves. I too had to R & R them both as the port side was weeping intermittantly. It could also be injectors or intake manifolds. All sorts of stuff. Take off that fuel rail cover and look around and see if you can spot the leak or general source of it.

Guy

Last week I had to use the wife's van to haul the boat around, so she drove the 750 for 3 days. Two days she left the headlights on and killed the battery, and I am ever so thankful for the discussions on the board, lest I would have no clue about getting into the car. But the key in the passenger side worked fine, and I later turned it backwards and synchronized the lock again. The third day she ran out of gas. I took some over and it cranked right up and ran fine. It ran fine for me after that.
Two days later (Friday) I needed the van again and she drove the 750. She was on the interstate, perhaps had just let off the gas at her exit, when the motor died and would not restart. A half hour later she tried one last time before calling the wrecker and it cranked fine and ran fine for another two days.

Today (Sunday) I drive about a mile to drop off my daughter and stop at a stop sign. As it comes to a stop it stumbled for maybe two seconds and dies. The tach was already idling, droped to zero, back up a time or two then stopped as if I had turned the key off. I tried to restart, the motor spins over smartly but does not fire at all. I waited 3 or 4 minutes, listened for the fuel pumps but traffic was too noisy, still no firing even though the starter spins fine.

Can't seem to get codes to read. Foot too slow? Have Check Control message. Like I do every day or two for three years.

Any suggestions? What about a fuel pump relay? But there are two on a 750, so wouldn't I be running on 1/2 engine instead of dead as a mackerel? I replaced one fuel pump last year. I smelled gas a couple of times last week while driving, but can find no evidence when I stop.

Anyway, any comments or suggestions would be appreciated. I have a Bentley and will soon begin tinkering, but since it runs fine now, I am not sure where to begin to diagnose.

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