fuel problem
Created by: AMXracer
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Last post: May 23, 2023 Member since:Dec 29, 2004
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Glad to hear you fixed it! Congrats.
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It was the k96 relay. I installed a new "used" fuse panel and she fired right up and runs great. Thanks for all of your help, Ken.
John
John
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According to the Bentley manual, the fuel pump relay # K96 is one that is soldered onto the backside of the fuse panel. So yes, you will probably need to replace the entire fuse panel board if the relay is bad.
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Thank you for the wiring diagram, Ken, that helps a lot. It is my understanding that if the relay in the kick-panel fuse box is bad that it is not replaceable and a new fuse panel needs to be installed. Is this correct?
I'll get to checking for bad wires/grounds.
John
I'll get to checking for bad wires/grounds.
John
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It certainly could be a bad electrical connection, or maybe a bad ground??
The fuel pump circuit is very straight forward:
The fuel pump circuit is very straight forward:
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Thanks, Ken, for the help you have given me. I some more info that I just discovered. As mentioned in my original post, I checked the cranking voltage at the disconnected fuel pump connector and got 11.4 cranking volts. I just repeated this test and got the same voltage. I then attached the connector to the new LPFP and back probed the cranking voltage. I got zero cranking voltage. I disconnected the connector from the new fuel pump and attached it to my old fuel pump. Again, zero cranking voltage.
Maybe the connector is damaged internally so that the pressure of being attached to the fuel pump renders it inoperable? There is a problem in the fuel pump wiring that doesn't like the circuit being completed when the connector is attached to the pump? Bad ECU? Why does it start and run fine when the fuel pump is direct wired from a separate battery and could this rule out a bad ECU?
Sorry for being a pest but I am already way above my mental capability by getting this far trying to solve the problem.
John
Maybe the connector is damaged internally so that the pressure of being attached to the fuel pump renders it inoperable? There is a problem in the fuel pump wiring that doesn't like the circuit being completed when the connector is attached to the pump? Bad ECU? Why does it start and run fine when the fuel pump is direct wired from a separate battery and could this rule out a bad ECU?
Sorry for being a pest but I am already way above my mental capability by getting this far trying to solve the problem.
John
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Probably the same.
Based on what you have replaced, it 'sounds like' the computer is not allowing full pressure based on inputs from other sensors:
The volume control valve is a part of the high pressure fuel pump.
Not sure what else we can suggest... it is very difficult to accurately diagnose a problem remotely...
Based on what you have replaced, it 'sounds like' the computer is not allowing full pressure based on inputs from other sensors:
Volume Control Valve
The volume control valve is connected by means of a two wire circuit to the ECM. It receives system voltage via the ECM main relay.
The ECM drives the volume control valve pulse-width modulated on the ground side.
The required fuel delivery pressure is determined by the engine-management system as a function of engine load and engine speed.
The pressure level is registered by the rail pressure sensor and transferred to the ECM.
The volume control valve is a part of the high pressure fuel pump.
Not sure what else we can suggest... it is very difficult to accurately diagnose a problem remotely...
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I had replaced the fuel pressure regulator attached to the rail. Is this the same as the pressure sensor or is it a different part?
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Maybe a defective fuel rail pressure sensor? - just a guess...
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Here's the deal: I bought a 2010 Mini S in July and drove it 100 miles to home. It ran great. After a week of driving it started showing signs of distress and finally left me stranded on the roadside. Using a scanner, I found that I had low fuel pressure so I went to work to try to solve the issue. At this point I have installed a new fuel filter, new LPFP, rebuilt HPFP, and new fuel regulator. If I jump from a separate battery to the fuel pump the car starts immediately and runs great with 700 psi fuel pressure. If I attach the fuel pump connector, the car will not start and produces negligible low pressure fuel pressure.
While it is running on the separate battery I checked the voltage at the fuel pump connector and it is getting alternator voltage, 14 volts. Checking the unplugged connector while cranking shows 11.4 volts which would seem to be enough to produce fuel pressure when reconnected to the fuel pump.
I have replaced the relay in the engine compartment and the fuse in the kick panel is good and is receiving full voltage.
I'm kinda stuck at this point so I am hoping that people smarter than me (that won't take much!) can chime in with some suggestions.
While it is running on the separate battery I checked the voltage at the fuel pump connector and it is getting alternator voltage, 14 volts. Checking the unplugged connector while cranking shows 11.4 volts which would seem to be enough to produce fuel pressure when reconnected to the fuel pump.
I have replaced the relay in the engine compartment and the fuse in the kick panel is good and is receiving full voltage.
I'm kinda stuck at this point so I am hoping that people smarter than me (that won't take much!) can chime in with some suggestions.