Too much fuel pressure - Fore Hat w/wiring - Returnless

[slow98cobra]

Hey Crew,

Just dropped my tank and added my new Fore Hat with improved GT pumps. Wired everything up and now I have way too much fuel pressure. Seriously, like 80 freakin psi. I used the wiring upgrade with the kit and wired the red wires from pumps to the brown/pink on the fpdm and the black from pumps to the red/black wire on the fpdm. Still returnless but when I turn on the key, pumps are going full tilt so thinking I just wired up to always on.

Anyone know exactly which wires should be connected by the fpdm from the pumps in the Fore Hat for a returnless setup?

 

[slow98cobra]

@04sleeper you still around by chance? I know you have a fun little following going on right now on FB, haha.

 

[2003RedfireVert]

I'm interested to see the solution. I want to go this route on my car. This is on back-order according to Fore.

 

[slow98cobra]

I was pretty fortunate to find a brand new one from someone that changed directions. Needle in the hay stack on eBay! They have been back ordered since the first part of 2021.

 

[01yellercobra]

It's been a while since I've done this, but isn't the brown/pink wire a constant 12vdc? I seem to remember that being the wire for triggering the relay in the wire upgrade.

Did you get rid of the stock plug and harness?

 

[MG0h3]

Pins 3 and 10 from the fpdm control the pumps. Have to dig up a diagram of the plug.


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[slow98cobra]

Here is what I was trying to use as a guide. Shows 2 FPDMs so hope it is right. I did keep the factory plugs and wiring to easily patch into the wiring for the fuel level sending unit. I’m just stumped right now. Pumps are loud, going all out when I turn on the key and I don’t even attempt to start. I’m wondering if I mixed up something on my FPDM relay for the wire upgrade.

 

[slow98cobra]

 

[MG0h3]

Not familiar with a dual fpdm setup. What’s with the extra relays? Power the second FPDM?



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[cobracide]

New pumps different than stock then you need a new tune. Pumps prime with key on.

 

[slow98cobra]

Not familiar with a dual fpdm setup. What’s with the extra relays? Power the second FPDM?



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I actually don’t have dual FPDMs but one single modded FPDM from Black306 with the wiring upgrade. The wiring upgrade with the modded FPDM came with a relay that I believe serves as a way to take power directly from the battery through a thicker wire when the on signal is detected.

New pumps different than stock then you need a new tune. Pumps prime with key on.

I just sent Kevin a message to see about updating the tune. Need a couple other items addressed as well and purchase the E85 tune(whole reason I’m doing this). I had SVT Focus pumps in before this so thought that I wouldn’t necessarily need to retune just for a pump swap. The SVT pumps would prime for a sec then get quiet. These just continuously run with the key on. It’s odd.

 

[cobracide]

I just sent Kevin a message to see about updating the tune. Need a couple other items addressed as well and purchase the E85 tune(whole reason I’m doing this). I had SVT Focus pumps in before this so thought that I wouldn’t necessarily need to retune just for a pump swap. The SVT pumps would prime for a sec then get quiet. These just continuously run with the key on. It’s odd.

With E85 you will probably need larger injectors than stock too.

 

[slow98cobra]

With E85 you will probably need larger injectors than stock too.

Got it covered! Running ID1050xs in it right now! Overkill but just setting the system up to have quite a bit of headroom in the future.

It has already been tuned for these by Kevin as well so hopefully it is a pretty simple tune update with a log or two because I added a SBTB since our last session as well.

Getting closer!

 

[MG0h3]

The fpdm controls the pumps via the ground; can’t recall if it’s pin 3 or 10. Been a long time.

If you’re taking power from the battery through the relay, that fine.


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[slow98cobra]

So I just double checked and I have the two red wires from the pumps going into pin 10 and the black wires from the pumps going into pin 3. I checked my FPDM relay and all looks good there. These things definitely don’t just prime with key on. They are going full on.

 

[01yellercobra]

New pumps different than stock then you need a new tune. Pumps prime with key on.

The tune has nothing to do with the pumps running full time. That's a mechanical issue. The voltage table is for when the ECU is reset for whatever reason.

 

[slow98cobra]

Well what a pita. Every single time, it doesn’t go smoothly and I spend hours redoing BS. Can anybody confirm 100% those are the correct wiring and pins on the FPDM before I just redrop the tank?

 

[MG0h3]

You shouldn’t have to drop the tank. You’ve got the wires running up into the trunk.

Why couldn’t you use the same wires that ran to the factory pumps?

I’ve never done the upgraded FPDM or whatever but it seems you’d just use the same wires that went to the original pumps.


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[04DeadShort]

Here is the info I followed 10 years ago when I did the dual fpdm on my 03. Still works fine. The black306 is the same way. Just dont worry about paralleling the 2nd fpdm. Is the black306 new or used. It's possibly bad and having no control except 100% output.

WestCoastMustangs.com

 

[slow98cobra]

You shouldn’t have to drop the tank. You’ve got the wires running up into the trunk.

Why couldn’t you use the same wires that ran to the factory pumps?

I’ve never done the upgraded FPDM or whatever but it seems you’d just use the same wires that went to the original pumps.


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That’s what I was thinking too. I’m going to drop the tank and look around. Just to make sure a line isn’t pinched or something else obvious.

Here is the info I followed 10 years ago when I did the dual fpdm on my 03. Still works fine. The black306 is the same way. Just dont worry about paralleling the 2nd fpdm. Is the black306 new or used. It's possibly bad and having no control except 100% output.

WestCoastMustangs.com

The FPDM was new when I installed it last year and everything was working perfect with my SVT Focus pumps. That wiring definitely reinforces what I was thinking and how it is currently wired. I’m going to spend some time today going through it again. I can’t believe this simple “drop in” install has turned into a frustrating experience. Honestly not worth it for an eaton car just wanting to run E85.