1998 Mustang GT Fuel Pump Relay HELP PLEASE!

1CeMaN

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Dec 14, 2009
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#1
Hey all, my friend is over and we CAN NOT find the fuel pump relay on my 1998 mustang gt.

My car cranks but will not start, so we want to try to replace the relay then the filter if that does not fix it.

While trying to do some research online, we keep getting mixed answers (trunk, under the hood)

Does anyone know for sure?

Please help asap!

Here are some pics of what we are working with...
Let me know what you experts think!


Pictures by TheBronxBull9 - Photobucket
its the first 6 pictures
 
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1CeMaN

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Dec 14, 2009
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#3
We dont think there is power going to it because we can not hear the pump when we turn it to on.
 
#4
That could mean a lot of things. Fuel pump could be bad, bad relay, blown fuse, inertia switch open. You should check if there is power at the pump with a meter and then go from there.
 

nyuk98gt

15 Year Member
Oct 10, 2000
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Chesterfield, MO
#6
GDawg:

Not stirring the pot here but isn't the FP relay integrated into the CCRM? (The Haynes manual does not show a relay for the '98 GT.) And, the CCRM is in the passenger wheel well behind the plastic liner. Teach an old dog a new trick!

1CeMaN:

Get a manual (Haynes or Chilton's or the Helm shop manual) and trace the wiring. That is the only way to know if there is a wiring/harness issue or the pump. I would start by direct wiring the pump. If it runs, then the pump is OK. If it does not run then the motor has failed and a new pump is needed. If the pump runs then you have to check the wiring, section by section.

Electrical stuff is usually not much fun.

HTH,

Chris
 

1CeMaN

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Dec 14, 2009
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#7
Ok so really weird...

My friend disconnects the negative from my battery... takes off the panel from the passenger sides and touches the wires (does not disconnect anything)

viola.... fuel pump now sounds when on, and all of a sudden it starts

weird.... any reasons as to why?

and he said he reset the ecu but only let it sit for a few seconds
 

GDawg

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Mar 22, 2002
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#8
Ok so really weird...

My friend disconnects the negative from my battery... takes off the panel from the passenger sides and touches the wires (does not disconnect anything)

viola.... fuel pump now sounds when on, and all of a sudden it starts

weird.... any reasons as to why?

and he said he reset the ecu but only let it sit for a few seconds
Maybe a pin was loose... :shrug:
 

GDawg

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Mar 22, 2002
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#9
GDawg:

Not stirring the pot here but isn't the FP relay integrated into the CCRM? (The Haynes manual does not show a relay for the '98 GT.) And, the CCRM is in the passenger wheel well behind the plastic liner. Teach an old dog a new trick!



Electrical stuff is usually not much fun.

HTH,

Chris
I love electrical stuff... :p

I've been in that kick panel recently but didn't pay attention.

On Shop Key wiring diagrams it shows the PCM Fuel Pump circuit goes to an external relay located next to the PCM. It also shows a Fuel Pump resister rear of right fender...

BUT... it also shows that after the relay and the resister it enters the CCRM to another relay.


98GTEnginePerformanceCircuit1of31000.jpg



98GTEnginePerformanceCircuit2of31000.jpg



98GTEnginePerformanceCircuit3of31000.jpg
 

nyuk98gt

15 Year Member
Oct 10, 2000
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#10
GDawg:

OK, you've given me a headache with those diagrams! They are much more detailed than the Haynes manual schematics. Now I've got to hunt down the FP relay in my car, lol.

Chris
 

GDawg

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#11
GDawg:

OK, you've given me a headache with those diagrams! They are much more detailed than the Haynes manual schematics. Now I've got to hunt down the FP relay in my car, lol.

Chris
In that second diagram toward the top is the relays. In the first is the PCM.
 

wmburns

SN Certified Technician
Aug 14, 2009
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#13
FWIIW, there are two fuel pump relays in the 98 GT. The main power rely is in the CCRM. The relay near the PCM is the fuel pump SPEED relay. In low speed mode, there is a ballast resister in series with the FP to slow it down when the motor's fuel needs are low. This helps to reduce fuel heating.

FWIIW2, a frequent problem with older Mustangs is water leaking into the PCM area. This causes corrosion issues that electrical parts don't like. And of course there's the usual "loose connection" theory.
 

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