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01 M Coupe S54 Fuel Pump Cutting Out - Looking for Help!

3K views 2 replies 2 participants last post by  mikefo 
#1 ·
Please see below for M Coupe S54 (close to M3) patient’s history:

Car Stalled and would not start after brief history of cutting out for a second or 2 while driving.

• Towed to BMW Dealer – Diagnosed as bad DME alignment. Paid for new DME.
• Drove home and after 2 days the car started in my garage but stalled pulling out. Once again had the car towed to dealer.
Replaced fuel relay. Stalled 4 miles away from dealer. Restarted after 2 minutes.
• I ordered a new air filter and MAF meter based on the idea the oiled cloth filter had soiled the MAF. I found that the at least once the car would re-start after unplugging the MAF. This may was likely a fluke related to whatever was causing the fuel pump to time out resetting. In any case the car has a new MAF.
• Problem persisted to the point where the car would sputter and stall every few minutes in city driving. It would stall. The Fuel Pump was not priming during the period the car would not start. After waiting for a few minutes it the pump would turn on and the car would start and run fine for a few minutes only to repeat the situation again.
• Returned to BMW - No problem found? On way home (2 miles away) problem repeated. Only could drive perhaps a mile before car would die. Wait a 5-10 minutes and the car would start again and drive another mile. Very frustrating.
• I ordered a fuel pump and filter and changed both out thinking a clogged filter could be the problem, and if not the filter then the fuel pump even though it made no grinding noise or anything like that. Replaced the filter and no improvement. Replaced the fuel pump and all problems had seemed to be fixed other than my car now smelling like gasoline. Very happy at this point!
• 2 days later it stalled again only to restart immediately and continue to run fine for 2 weeks.
• 2 weeks later (Friday) I let it idle of 3 minutes as I grabbed coffee in the AM. The car stalled and would not start again until I let it sit for a few minutes. It then started and stalled out again. Waited another 2 minutes and everything was fine except I was very pissed.
• Sunday, drove to lifetime fitness in AM. Car stalled at a light 1 mile from house. It started up after a few cranks. On way home from lifetime it stalled again going 40 MPh down 111th. Kept in gear and after around 3-4 seconds the engine recovered and continued to run until I got home.
• Later Sunday, I drove the car to bike shop on 71’st street with no problems but on way home is stalled out on riverside. Would not restart after waiting for 5-10 Minutes. No fuel pump prime. Unconnected the MAF cable (willing to try anything) still no start. Called AAA for a tow. While on phone car started and ran fine home.
• Frustrated, at home I took the seat out of the car and looked for loose or wire that was somehow being shorted out. Found a connecter to the door shut detector loose (thought that it may have something to do with the ground of the fuel pump so taped it up so it would not jiggle. While carpet was up found 2 screws from the fuel pump cover that someone had let drop in previous examination of fuel pump. (Not sure fuel pump was replaced but cover was removed at some point in the past as carpet was opened from the perforated new condition.
• Took car for ride at 10 pm to see if things improved. Car cut out for 1 second rounding a curve and stalled 500 yards later 4 miles from house. No fuel pump prime. After 10-15 minutes car fuel pump primed and car started and ran for 1.5 miles. Only to stall again. Again waited for 10 minutes for fuel pump to reset or prime and drove car strait to your parking lot. Drove car around parking lot 10 times to try and get condition to repeat itself but wife was getting pissed waiting so I parked it.

General conclusions:
1. I did something when I replaced the fuel pump to clear the symptoms for 200 miles other than the one quick stall.
2. Car has never stalled at idle. Must be driven to initiate conditions. Problem seems to be initiated by movement.
3. I suspect a short in the wiring but I have no idea where other than someone on a message the M Coupe board reported having a “DME grounds come loose causing the same symptoms . One of the symptoms: the fuel pump will not run or will run intermittently. It's the ground on the back of the passenger-side shock tower. After that occurrence (which stranded me in the wee hours of a holiday weekend), I put a jam nut on the existing nut. It's worth checking it.” - Probably worth checking that connection.

Plean to check the ground. Anyone have a similar experence.

Please let me know what you think. I am beyond frustrated!
 
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#2 · (Edited)
check your battery connections in the trunk (most likely not your problem), and please check your ignition switch. Most likely an ignition switch, hard to catch it when it fails. You should just replace it due to age and wear also. let me know if this fixes. You may also have a crankshaft sensor, fuel pump relay, or main relay intermittently failing but also very hard to catch and replacement is only way to verify repair.
 
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