no fuel pressure
06-20-2017, 03:09 PM
#2
Moderator
Welcome to the forum. How are you measuring the lack of fuel pressure?
06-20-2017, 04:42 PM
#3
I have a fuel pressure gauge hooked up to my fuel line going to the fuel rail. 0psi at all times. I cant get the fuel pump to actuate. tried manually powering the fuel pump at the fpdm and still nothing.
06-20-2017, 04:45 PM
#4
Moderator
You can try powering it at the top of the tank. If that doesn't do it then it might be time for a new fuel pump.
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laterbabes (06-22-2017)
06-20-2017, 10:32 PM
#6
05 5.4l 3v s.crew lariat
I believe fuel pump relay is before FPDM
If it won't run from fpdm module plug then you should try it at the gas tank . If she won't run there shes bad .
Double check your connections that you are jumping to at fpdm ,check colors going to pump.
Pink /blk stripe positive
brn /wht stripe negative
I would use my own 20 amp fuse lead straight from battery and a negative straight from battery don't trust metal grd .
I hear the fuel pump relay soldered on rear of main fuse panel passenger side .
Double check your connections that you are jumping to at fpdm ,check colors going to pump.
Pink /blk stripe positive
brn /wht stripe negative
I would use my own 20 amp fuse lead straight from battery and a negative straight from battery don't trust metal grd .
I hear the fuel pump relay soldered on rear of main fuse panel passenger side .
The following users liked this post:
laterbabes (06-22-2017)
06-22-2017, 08:58 AM
#7
Guys, I tried actuating the fuel pump right at the fuel pump connector and I can get the fuel pump to run. I removed the cab off the frame again to double check the whole wiring harness going to the fpdm and the fuel pump. didn't find anything. I also noticed that I wasn't getting voltage from my pcm to the fpdm on my fpdm control circuit. I read somewhere that the fpdm has to be flashed by Ford...? I re applied the cab and no the truck wont even crank. I scanned it and it says its not in park or neutral. it shows im in park on the cluster and I know im in park down at my trans.
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06-22-2017, 01:00 PM
#8
05 5.4l 3v s.crew lariat
The fuel rail pressure sw tells pcm to send drv pwr to FPDM
I thought you said jumping power to fuel pump at fpdm connector didn't work ? I would double check . sounds like now your fuel rail sensor to pcm or pcm output to fpdm is in trouble ?Either that or your plug info at fpdm is not correct ,check colors and retry .clean plug my plug was jammed with a bad gasket .
Are you sure you are at looking at correct pins versus colors . Clean off wire colors and lay it out on a piece of paper. That area tough to work in and pins hard to see or deal with. You may need to peirce wires with a pin to get a good reading . Could also be a bad plug .
Pin 5 (WHITE) should be POSITIVE from fuel relay thru inertia sw . PCM brings fuel relay on ,circuit appears to be powered by fuse 34.
Power to pump is brn/wht(2 ) and pos on pink/blk (4). Another thing to check is your ground to fpdm pin 3 goes to frame rail grd for its negative power . Corrosion may have ruined that grd . Clean and redo for sure . Blk/yel to grd s411 point . Take a powered lamp and see if a good grd on this pin 3.
Are you sure you are at looking at correct pins versus colors . Clean off wire colors and lay it out on a piece of paper. That area tough to work in and pins hard to see or deal with. You may need to peirce wires with a pin to get a good reading . Could also be a bad plug .
Pin 5 (WHITE) should be POSITIVE from fuel relay thru inertia sw . PCM brings fuel relay on ,circuit appears to be powered by fuse 34.
Power to pump is brn/wht(2 ) and pos on pink/blk (4). Another thing to check is your ground to fpdm pin 3 goes to frame rail grd for its negative power . Corrosion may have ruined that grd . Clean and redo for sure . Blk/yel to grd s411 point . Take a powered lamp and see if a good grd on this pin 3.
07-25-2017, 12:19 PM
#10
I thought you said jumping power to fuel pump at fpdm connector didn't work ? I would double check . sounds like now your fuel rail sensor to pcm or pcm output to fpdm is in trouble ?Either that or your plug info at fpdm is not correct ,check colors and retry .clean plug my plug was jammed with a bad gasket .
Are you sure you are at looking at correct pins versus colors . Clean off wire colors and lay it out on a piece of paper. That area tough to work in and pins hard to see or deal with. You may need to peirce wires with a pin to get a good reading . Could also be a bad plug .
Pin 5 (WHITE) should be POSITIVE from fuel relay thru inertia sw . PCM brings fuel relay on ,circuit appears to be powered by fuse 34.
Power to pump is brn/wht(2 ) and pos on pink/blk (4). Another thing to check is your ground to fpdm pin 3 goes to frame rail grd for its negative power . Corrosion may have ruined that grd . Clean and redo for sure . Blk/yel to grd s411 point . Take a powered lamp and see if a good grd on this pin 3.
Are you sure you are at looking at correct pins versus colors . Clean off wire colors and lay it out on a piece of paper. That area tough to work in and pins hard to see or deal with. You may need to peirce wires with a pin to get a good reading . Could also be a bad plug .
Pin 5 (WHITE) should be POSITIVE from fuel relay thru inertia sw . PCM brings fuel relay on ,circuit appears to be powered by fuse 34.
Power to pump is brn/wht(2 ) and pos on pink/blk (4). Another thing to check is your ground to fpdm pin 3 goes to frame rail grd for its negative power . Corrosion may have ruined that grd . Clean and redo for sure . Blk/yel to grd s411 point . Take a powered lamp and see if a good grd on this pin 3.
FPDM cycle seems to be stuck at 16 acording to torque.
Was not able to undone FPDM ground so i cut the wrap and tested with short circuit with frame, not sure if that proved anything...?