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-   -   Loses fuel pressure when parked (

squabe 01-26-2013 11:27 AM

Loses fuel pressure when parked
hello bimmerfest i am new to the board but have used many tips from the board. I would appreciate any suggestions. I have a 97 e38 with m62 motor I recently changed fuel filter and two weeks later my car would lose fuel pressure after sitting for 5 minutes or so. I went under the car and noticed while the car was running the fuel line had plenty of pressure soon as i turn the motor off withing 5 minutes it would lose pressure. Trying to fix this i have changed the fuel pressure check valve in the tank, the regulator and fuel pump. After car cranks for a while it starts and runs perfect! I have noticed no gas smell coming from from the lines or around the car. Please help. Car has 250,000 and runs great!
i have also changed osv, cooling pipes, intake man gaskets, and crank position sensor.

BMWFatherFigure 01-27-2013 02:37 AM

Try clamping the rubber parts of the fuel supply pipe and fule return pipe, one at a time. That will tell you which way the pressure is being lost. If neither make any difference (ie you still get a loss) it points to leaking injectors or an external (pipe) leak. Not much fuel needs to leak to reduce the pressure. Also join in a gauge if possible to watch the pressure go down.

joyism5 01-27-2013 04:41 PM

After checking the above mentioned I would check if the fuel injectors are leaking. Order some new o-rings, remove them and check you tube for tutorials how to check them and clean them also. There are a lot of videos. If you want to find which one is leaking you could check the spark plugs for deposits.

BMWFatherFigure 01-27-2013 11:24 PM

If you suspect leaking injectors get them rig cleaned and tested. Bit $ but the results are :thumbup:

squabe 01-28-2013 06:16 AM

Thanks guys for your reply. I am going to clamp and check fuel lines. If injectors were leaking would I smell fuel? I have recently changed injectors but had this problem before hand.

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