Replaced fuel pump and it still won't prime.

Gurahl

Gurahl

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Fort Riley, KS
Title says it all. My fuel pump wasn't priming so I replaced it with a Bosch from Napa. Now the new pump won't prime either. I have swapped fuses and relays. I am getting a little desperate. How can I test to see if the pump is getting power without dropping the tank again?
 
There is no pressure at the rails. The fuel pump is not priming at all. I jumped the original pump from a 12 volt source and it came to life. That leads me to believe that it is something else that is causing the pump not to prime. WHat that might be...I have no idea.
 
DLF- It is a 97.

Frogman-So other than putting a different one in how can I check the VCLM?
 
Alright, I have located my FPDM. Which wire is the output? I suppose I should say what is the correct way to check this? My searches only turned up what it is and where it is.
 
Gurahl said:
Alright, I have located my FPDM. Which wire is the output? I suppose I should say what is the correct way to check this? My searches only turned up what it is and where it is.
Click to expand...

Here's a schematic. Check for voltage between pins 3 and 10 on the FPDM.

Good night and good luck. ;)

FPDM.jpg
 
Thank you DLF. I will check it in the morning, after my wife has forgiven me enough for working on my car all day to turn the key while I check the voltage.:rolleyes:
 
Okey dokey. I have checked the voltage between 3 and 10 and there is nothing. Do I need to check anything else before I go to the junkyard and throw a part at it? What sends signal to the FPDM and which pins does it receive it at?
 
After some more research I found this picture of the pinout on a Mustang fpdm. I checked the voltage going into the FPDM from the PCM and it was 3.7. Does this sound right for the control signal? Also other sources I found said that the FPDM module for our cars is the same as an 01 Mustang GT if this is true it might be easier for me to find one from a Stang than to try to find a Mark.
 
Gurahl said:
Okey dokey. I have checked the voltage between 3 and 10 and there is nothing. Do I need to check anything else before I go to the junkyard and throw a part at it? What sends signal to the FPDM and which pins does it receive it at?
Click to expand...

Check the output voltage of the IFS at pin 9 of the FPDM.

If there's 12v, then either the FPDM, the PCM, or the wiring between them is bad.

If there isn't, then check the input to the IFS and the IFS itself (it could be tripped).

Keep working back until you find the problem.

FuelPumpRelay.jpg
 
Gurahl said:
I checked the voltage going into the FPDM from the PCM and it was 3.7. Does this sound right for the control signal?
Click to expand...

Yes.

Gurahl said:
Also other sources I found said that the FPDM module for our cars is the same as an 01 Mustang GT if this is true it might be easier for me to find one from a Stang than to try to find a Mark.
Click to expand...

I don't know, but I've read that also.
 
DLF said:
I mentioned that, we'll see what he finds.
Click to expand...
LOL!! I was thinking fuel pump switch too. I had no idea what "IFS" was. My dumb ass was wondering why he needed to check the Indipendant Front Suspension. :lol:
DLF, usually knows whats up though so I didnt question it.
 
Well thanks to the knowledgable group of people here I discovered that it was my FPMD. 27 dollars and a trip to the junkyard later I have a running vehicle. I pulled one out of an 01 V6 mustang. Just for future reference ALL 99-04 mustang FPMDs are the same. Hey at least I got a new fuel pump out of it!;) Thanks again guys.
 
Gurahl said:
Well thanks to the knowledgable group of people here I discovered that it was my FPDM. 27 dollars and a trip to the junkyard later I have a running vehicle. I pulled one out of an 01 V6 mustang. Just for future reference ALL 99-04 mustang FPDM's are the same. Hey at least I got a new fuel pump out of it!;) Thanks again guys.
Click to expand...

You're quite welcome, glad you got it running.

Donations gleefully accepted. :D
 
A new problem has reared its ugly head. After running perfectly well it is now running horribly and dying as if it were out of fuel.
 
Gurahl said:
I didn't change the fuel filter coul that cause it?
Click to expand...

if your old pump was going out, then yes is could have tossed some dirt into the filter and clogged it, Fuel filters are pump killers. people to lazy to find and replace them will cause you sever headachs in the future.
GL
Bill
 
Most places will not warrant their fuel pumps unless a fuel filter is purchased at the same time. There is a reason for this!!
 
Yes, I agree, I had to replace my fuel filter after installing a new fuel pump. After the installation of the new fuel filter the car ran like it was supposed to.
 
Well I replaced my fuel filter and my car f%^%ing exploded!




Just kidding. It is running but I am going to avoid saying whether it is fixed or not. It turns out I had to replace 3 coils and the filter. Oddly enough I am now getting a Pending P0171 and I have a P0174. Considering all the parts that have given up the ghost recently what are the odds that BOTH O2 sensors are going? Is there a check I can do, or you think it is more likely that I have a vacuum leak? BTW I have learned my lesson about half-assing a job.
 
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