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Old 12-14-2019, 12:48 AM
Jeffriehunter Jeffriehunter is offline
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Mein Auto:
No fuel pressure - please help

01 740i - no pressure at fuel rail. We think this started with a tank of bad gas (water). That tank was almost completely run out. Codes to random misfires and bank 2 lean, but car was running (and decent pressure at rail) but surged. New plugs and swapped coils, no change. Replaced fuel filter, had milky crap inside. Car still ran. Then car stopped running, at cranking hardly no pressure at rail. Replaced fuel pump, sill little pressure BUT now fighting dying battery. Swapped relays still little pressure. Some, but not dpraying hard from rail schrader. Fuse is good. We are baffled.....open to thoughts or suggestions. All yhis happened the morning after a fill up, car was running awesome prior to. Recently rebuilt motor, restored car.
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  #2  
Old 12-14-2019, 09:53 AM
Mayorchuck Mayorchuck is offline
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Mein Auto: '96 740iL
I would not discount low voltage if your battery is dying. The two large wires on the fuel pump connector is the + and - to power the pump. You could try using clips to hook direct 12v to see if it improves the pressure. I had a similar pressure issue with a different car after replacing filter. I used a piece of small copper pipe to bypass the filter and it fixed the issue. Filter was bad right out of the box. Those fuel pumps have filters on the bottom of them so I wouldn't think anything of size would get past and into the hose.

Are you having a parasitic draw issue with the battery?
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Old 12-14-2019, 04:05 PM
Jeffriehunter Jeffriehunter is offline
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No parasitic draw.......just ran it down during the trying to start it process.

Where are the big wires you are talking about to power the pump directly?
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Old 12-14-2019, 05:23 PM
Jeffriehunter Jeffriehunter is offline
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Ok.......now its throwing P0345....camshaft position sensor code bank 2.

I swapped from side to side and it threw the same code. Bad sensor or something else since the code disnt change after swapping sensors side to side.
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Old 12-15-2019, 07:57 AM
Jeffriehunter Jeffriehunter is offline
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Ok......camshaft position sensor issue fixed!! Was the wheel bdhind sensor in bank 2. Removed valve cover and tightened.

Cranks now with no codes!! Yah.

But syill no fuel pressure at rail. I can hear pump running when car is cranking.

??????
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Old 12-16-2019, 03:23 AM
lenwib lenwib is offline
Lennart
Location: Gothenburg, Sweden
 
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Mein Auto: BMW 750 iL -99
Have you considered this pressure regulator system: https://www.realoem.com/bmw/enUS/sho...diagId=13_0811
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Old 12-17-2019, 08:27 PM
Jeffriehunter Jeffriehunter is offline
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Replaced that as one of the first pieces.
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Old 12-18-2019, 11:44 AM
lenwib lenwib is offline
Lennart
Location: Gothenburg, Sweden
 
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Mein Auto: BMW 750 iL -99
So then are (at least) two possibilities.

1. The new pump is making noise but doesn't work.

2. Your new filter is of the same kind as the one that Mayorchuck experienced.

Or a last suggestion,
3. Too little gas in the tank. Happened before...
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