Dead Fuel Pump

[ledzilla]

Looks like my fuel pump finally bit the dust. For several years now when it sat over the winter but didn't have the pump primed every now and then by turning the car on (but not actually starting it), the pump wouldn't work. I'd have to turn it on and off repeatedly until the pump got unstuck. Sometimes it required bypassing the FPDM. But, this winter I've completely forgot about it and tried to fire it up the other day with the lovely weather we got around Chicago. Couldn't get the pump to run, even after the FPDM bypass (which never took more than one or two tries).

Are there any good pump replacements out there that don't require full assembly replacement? I know most aftermarket stock replacement fuel pumps kind of suck, but I was wondering if there was something that was good. I haven't seen anything conclusive outside of an OEM replacement assembly which can be really expensive and possibly not stocked.

[justbob]

Almost sounds like more of a relay issue.


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[ledzilla]

Not a relay. I tested the power leads into and out of the pump and FPDM. The power has to go through the relay first, then the inertia switch, and then it reaches the FPDM. A full 12v was reaching the FPDM.

[BLACKMARAUDER04]

fuel pumps go out all the time on panther cars..... especially if they sit for a long period of time.

[SilverPhoenix]

fuel pumps go out all the time on panther cars..... especially if they sit for a long period of time.

Can confirm...between Aug 2019 and Oct 2021 I put maybe 500 miles on my MM; December 2021 I had to have the fuel pump replaced...

[ledzilla]

Yeah, that's why I was trying to make sure the pump didn't sit idle for too long, once I realized it was being an issue. But this winter I just completely forgot to keep up on it.

[ledzilla]

So, is there a reliable non-OEM pump for a non-boosted car out there to be had?

[blazen71]

Walbro. I've never had a 255lph go bad. But i'm not sure how different lph pumps work with tuning a returnless system? I run a return system. Walbro makes smaller pumps you'd just have to figure out which one to use.

[crouse]

Have you checked the PFDM - Fuel Pump Drive Module? It's in the trunk on the left side by the CD changer. A few years ago, my Marauder wouldn't start. It would spin over but would not fire. I thought it was the fuel pump, so I had it towed to a shop. They went to pull it into the shop and it started just fine. I went through many times when it would start then would not. Finally unplugged the FPDM, cycled the key a few time (not sure if that was necessary) then plugged the FPDM back in and it started just fine. I bought a used FPDM from a member here and swapped it out. Ran fine until a few week ago when I went to start my Marauder after sitting for 2 or 3 weeks. It would spin over but not fire. Unplugged the FPDM, cycled the key a few times, plugged the FPDM back in and it fired up just fine. I bought another FPDM from a Grand Marquis at a salvage yard just to have another spare.

[ledzilla]

Yes, I did, as was previously mentioned. In fact, I bypassed the FPDM to rule it out and the pump still wouldn't operate.

[mustangeddie]

Are there any good pump replacements out there that don't require full assembly replacement? I know most aftermarket stock replacement fuel pumps kind of suck, but I was wondering if there was something that was good. I have a brand new Motorcraft Ford Gt pump if you are interested. None of the GT hanger assembly works you just remove the pump from the GT hanger & install it in the Marauder one. It's a simple swap & didn't require a tune adjustment. Just put one in my car it is a Walbro 265lph unit.

[ledzilla]

I have a brand new Motorcraft Ford Gt pump if you are interested. None of the GT hanger assembly works you just remove the pump from the GT hanger & install it in the Marauder one. It's a simple swap & didn't require a tune adjustment. Just put one in my car it is a Walbro 265lph unit.Thanks for the offer. For now, though, I'm just trying to see what the best options are and plan out when I can make a purchase. This issue isn't all that high on my priority list presently.

[BLACKMARAUDER04]

I use the Bosch brand pump. Bosch made the OEM unit. I purchased it from Amazon.


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[ledzilla]

So far overall I've seen mention of the following fuel pumps being recommended:

> Bosch
> Delphi
> Aeromotive 340

Although I must admit that I was under the impression that the OEM unit was manufactured by Delphi.

[ledzilla]

w00t!!

I haven't yet replaced the pump, but I got it running again. I put a few gallons of detergent premium fuel into the tank along with a can of SeaFoam, and let it sit. Every now and then I performed a bypass on the FPDM to run full power through the pump to try and unstick it. It finally worked. Now I won't need a tow truck to move it back into the garage.

[jaywish]

Does jumping power from the key on hot at the relay socket to the center pin of the relay socket bypass the fuel module?

[ledzilla]

There are two pairs of pins to jump at the FPDM to run full 12V to the pump. Without a return system, it's probably not advisable to run it long term like that. Plus it throws a code with the module being disconnected.

[jaywish]

Thank You. I just wanted to see if the pump would spin. Had not intended to run it much that way. Guess I will need to get out the diagram. If the jump at relay passes the FDPM I will let you know.

[ledzilla]

If you want to bypass the module, let me know. I have a couple photos of the connector marked up that will make it easier.

[jaywish]

The fuel pump relay sends fused power to the fuel shutoff switch then to the Fuel Pump Module. So jumping the relay does not send power direct to the pump just to the FPM by way of the inertia shutoff switch The FPM then needs to be bypassed to test the pump.

[jaywish]

I assumed the black and the White need to be jumped to BN/WH and the PK/BK. I would have guessed White to BN/WH & Black to PK/BK but that seems wrong if the labels are correct in the electrical diagram manual.

According to the book at the FPM connector :
Black is ground and White is hot.
The 2 motor leads show PK/BK as power to pump and BN/WH as return power from pump.

So that leaves me a bit confused. Does the motor ground through the tank/tank connector or is the return power (BN/WH) from tank the ground? So if the motor gets ground by a wire from the pump side connector or the tank itself then at the FPM connector only the white needs to be jumped to the PK/BK ? It seems counter intuitive as I would have suspected the BN/WH would have carried power to the pump. (White to White.) but I would have been WRONG.

[ledzilla]

Power and ground both go through the FPDM. I'll show you how I jumped the wires. The two wires marked in blue were jumped together, and two marked in red were jumped together. So long as the relay is working and the shutoff hasn't been tripped, it should fire up the pump.

I my case, I had to repeatedly connect amd disconnect to try to unstick the pump. If the pump isn't completely toast, you should at least hear a small thump when the pump receives the full 12V.https://uploads.tapatalk-cdn.com/20231024/f36832173d0dc1d7c303f5b2280c54 d1.jpghttps://uploads.tapatalk-cdn.com/20231024/4a9f0e737988d4dd6ddb933dc9403f 2c.jpg

[jaywish]

Great perfect illustration.
The Black gets jumped to the BR/WH providing pump ground
The White gets jumped to the PK/BK providing 12V hot.

I am going to try that now. So in run white should be 12V showing the fuse, relay and inertia switch are good.

Thank you.
Jay

[jaywish]

Guess pump is toast.

Had 12v on white in run and a good ground on Black. No noise when jumped.

Last night I ordered the Delphi complete pump unit from RA. about $200 plus shipping along with other misc stuff e.g. a fuel filter, spare relay, some fomoco rear pads and Trico Ultra wipers for all the cars. They, the wipers, are still made in USA and last a very long time. I recommend the Trico Ultra line.

I appreciate the information.

Jay

BTW I am not going to follow the service manual and remove the tank. Going to try and sneak it in. We will see how the removal goes tomorrow. Won't have the parts till probably later tomorrow night. At least that is my plan HA HA.

[ledzilla]

Were you able to verify power first? I only ask given that you heard nothing when testing.

[jaywish]

Yes had both 12v and ground on white and black respectively.

[ledzilla]

Groovy. I actually just got mine replaced a couple weeks ago. It finally got stuck for good. I dropped it off at a shop and they installed an OEM pump assembly.

[jaywish]

OK long live the pump!

[jaywish]

Installed the Delphi Pump today. Would have been nice to have the motorcraft one but hopefully this will do. The PITA of the job is the connector for the pressure switch at the top of the tank on the right side. After many failed attempts I bent some other tool into the shape I needed to unclip and remove the connector. Now the new connector will not latch as yet. Otherwise it is done and the car runs. I will post pics with a writeup when I am totally finished. Perhaps it can be added to the tech articles.

[ledzilla]

And that's why I elected to just have a shop do it. I tried tinkering with that connector and decided it wasn't worth the effort.

[blazen71]

Installed the Delphi Pump today. Would have been nice to have the motorcraft one but hopefully this will do. The PITA of the job is the connector for the pressure switch at the top of the tank on the right side. After many failed attempts I bent some other tool into the shape I needed to unclip and remove the connector. Now the new connector will not latch as yet. Otherwise it is done and the car runs. I will post pics with a writeup when I am totally finished. Perhaps it can be added to the tech articles.
The easy way is to just cut the wires to the pressure switch. Then reconnect with butt connectors and good heat shrink. In the past, I chose the hard way as you did and didn't feel bad about it.

[jaywish]

Splicing is my backup. I am going to try and plug the old harness in. If it connects properly I was thinking of trying to swap the new wires into the old connector. It is not the latch part that is the problem it is the bottom half of the connector where the contacts are that will not slide into place. Wish I had a snake camera to see in the connector.

[blazen71]

Splicing is my backup. I am going to try and plug the old harness in. If it connects properly I was thinking of trying to swap the new wires into the old connector. It is not the latch part that is the problem it is the bottom half of the connector where the contacts are that will not slide into place. Wish I had a snake camera to see in the connector.
Put some dielectric grease on the plug. It may help lube the connection and allow it to fully seat.

[jaywish]

I am going to try and get a little mirror in there.

[jaywish]

No go with any mirrors I had so I tried the old connector and it fit right in. I decided to swap connectors but getting the lock out of the old connector did not work easily & I did not want to trash it in case I needed to splice wires and use old connector. So I stared at both connectors side by side for an extended time till I started to see the very tiny differences in pin placement and thickness as well as a very slight bit of off center in the male part of the connector which is surrounded by a sheath.
So I made very very tiny tweaks to those 3 things Then begged for permission from the socket and shoved it in. Everything clicked and it felt good.

[blazen71]

I love it when a plan comes together!

[jaywish]

Right you are!