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Discussion Starter · #1 · (Edited)
So I go to lunch this morning. Car's running fine, no codes. Get back into the car after lunch and it starts, idles roughly and dies immediately. Further starting attempts result in occasional weak catch and immediate d e a t h. So I figure fueling. Check fuse 32 in the glovebox and 54 in the trunk, replace them with known good fuses - no dice. After searching, leaning towards fuel pump relay or the fuel pump itself. There's a lot of confusing/conflicting information on this forum about which relay the FP relay actually is but I think I have it nailed down as the tall black relay in the trunk, marked EKP. I also know the testing procedure to determine whether it's the pump itself or the relay. Am I missing any other relays anywhere that I need to look at, fueling-wise? Any other common failures that would cause a no-crank situation? My brother's got a 540i from 2001 so when I get it towed home, can I swap in his EKP relay and see if that does anything? Fuel filter is a year old, car has 103k on it, the fuel pump has never been changed to my knowledge.
 

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With over 100K in mileage, I would replace the fuel pump regardless of the ultimate cause of the current
problem, but that's just my opinion.

The tall, black relay marked EKP is the fuel pump relay, as you have suspected. As for the 540i part swap, I
believe the cutoff point for differences in fuel pump relay location for non-M5 was 09/2000, when the relay
was moved from the rear to the glove box area. I suspect you will not find the same tall, black relay on the
540i, since the M5 has a higher current draw due to the 5 bar pressure requirement.

If you want to check whether the relay is at fault, remove it and the jumper pins 30 to 87. For the test jumper,
buy a universal-type fused harness which is avail at most auto parts store. It's simply a fuse holder with pigtail
leads at each end. Install a 15 amp fuse for the test.

Regards,
Alan
 

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Discussion Starter · #3 ·
Update: after much testing, it seems as if the pump is deader than the parents on Party of Five. Applying 12v directly to it does nothing, there is no resistance between the terminals, nothing. The EKP might be faulty too - maybe it went bad and drove the pump to kill itself? Either way, not fun. Cheapest pump I found was $302 at DDM Tuning - anywhere I can find these things cheaper? Makes me miss my Audis and their 80$ pumps. Gotta pay to play, I guess.
 
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