Need help w/ Dual FPDM's & Dual GT fuel pumps

[Loco1234]

Hi all ,
I just completed my Dual GT fuel pump & Dual FPDM's upgrade. I also installed the lethal performance upgraded wiring kit. the original FPDM was a modified one... However it is not giving me enough fuel to do anything other than idle... I do wanna start by trying to find a simple wiring diagram because I don't believe I made any mistakes but the car isn't running properly... Does anyone have a simple wiring diagram they can post for me..?
If not any suggestions on where to begin? Im almost 100% posisitive I wired the pumps correctly but is it possible to wire a GT fuel pump in reverse.
FYI If I unplug a single FPDM the car will still idle & the same is true if I unplug the other FPDM...but will obviosly die if I unplug both.
I wire the relay as such: white to ground & green to 12c power.
While doing the upgrade I also drilled out the stock fuel hat w/ 2 bulkhead fittings & now have AN6 running from each pump to a Y block outside the fuel hat... Then used my existing AN8 fuel line all the way up to the engine etc... existing upgraded fuel rails & existing 60LBS inj.

What do you guys think? Do I need to ask on a mustang forum or do we have the answer... LOL

[DTUB]

If you wired your pumps backwards you won't get any flow out of them.

[Blown3.8]

Any check engine lights? You only want to hook up one of the fpdm status wires. Let me go check Sherms car its here.

[Blown3.8]

Ok only hook up one of the green/yellow from FPDM to ecm. Wire both blue/orange together to ecm, brown/white is pump ground to FPDM, pink/black is FPDM out to pump positive, and white is hooked to BAP out to FPDM. And use the white wire out of inertia switch to trigger the relays.

[pacammer]

Both Loco1234 & I are working on this & still haven't corrected it... The harness came pre-wired from lethal performance so I'd expect they wired it correctly... I found instructions on their site & all looks to be correct & I even tried to flip the reds going to the pumps incase I had them crossed... but no result... theres only enough fuel pressure for idle nothing more... I confirmed the pumps started before installing & can hear them start up when I put the key to on...
I put volt meter on boths leads to the pumps & they are showing 10.3V on pump 1 & 10.8V on pump 2 when I flip key to on... but settle down to less voltage after intial startup. Same is true for the amperage I observed during key on & after. (about 9A for both during initial key on & then 4A after)

However I don't know what voltage & amps I should bve seeing...
It can't just be the fuel sox are bunched up...can it... I would expect them to flow beyond idle even if they were...

[Local Boy]

Are you using the "L" shaped ones?

I believe these ones tend to crunch into the rear wall

Aloha

[FordNut]

Sorry I don't have much help to offer. I have twin GT pumps but use a single upgraded FPDM along with a BAP. Could it possibly be a programming issue? When I upgraded from twin Cobra pumps to twin GT pumps I had to change the PID's in my tune to keep the fuel pressure from being extremely erratic.

[Blown3.8]

The mustang wiring is different then the marauder wiring. The green/yellow is a different function between the 2 cars amongst the others too.

[Loco1234]

Hmmm I wonder if I have to re-wire the Lethal Performance "prewired" upgraded wiring kit to account for the change from a Mustang to a Marauder...?
Has anyone else gone with this same setup?
Dual GT pumps & Dual FPDMs w/ Lethal Performance upgraded wiring kit?

Lethal Performance install instructions:
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http://docs.google.com/leaf?id=0BypL...ut=list&num=50
http://docs.google.com/leaf?id=0BypL...ZjFiMzY2&hl=en

[Glenn]

Hi all ,
I just completed my Dual GT fuel pump & Dual FPDM's upgrade. I also installed the lethal performance upgraded wiring kit. the original FPDM was a modified one... However it is not giving me enough fuel to do anything other than idle... I do wanna start by trying to find a simple wiring diagram because I don't believe I made any mistakes but the car isn't running properly... Does anyone have a simple wiring diagram they can post for me..?
If not any suggestions on where to begin? Im almost 100% posisitive I wired the pumps correctly but is it possible to wire a GT fuel pump in reverse.
FYI If I unplug a single FPDM the car will still idle & the same is true if I unplug the other FPDM...but will obviosly die if I unplug both.
I wire the relay as such: white to ground & green to 12c power.
While doing the upgrade I also drilled out the stock fuel hat w/ 2 bulkhead fittings & now have AN6 running from each pump to a Y block outside the fuel hat... Then used my existing AN8 fuel line all the way up to the engine etc... existing upgraded fuel rails & existing 60LBS inj.

What do you guys think? Do I need to ask on a mustang forum or do we have the answer... LOL

Just curious - why did you think you needed this type of fuel set-up? Are you running over 500 HP.

Glenn Ford

[RocsMerc]

Just curious - why did you think you needed this type of fuel set-up? Are you running over 500 HP.

Glenn Ford

I saw his Dyno sheets at Carlisle this year. Simple answer, YES he is!

[Loco1234]

Just curious - why did you think you needed this type of fuel set-up? Are you running over 500 HP.

Glenn Ford

ya my last run on a Mustang Dyno I ended up w/ 623RWHP & 588RWTQ. However this was when I still had the T-trim on the car. Now I have installed the JT-trim and I was already running short of fuel with just the dual GT fuel pumps & a mod'd FPDM. So now I needed to install a 2nd FPDM & upgrade all of the wiring to the pumps. WHile I was at it I also upgraded the fuel socks & & ran AN6 from each pump to a Yblock into AN8 to engine. this got rid of the corrigated tubing in the tank... (less pressure drop)

I fully expect to hit about 700RWHP on the Mustang dyno once this is complete. That should put me around 800HP @ flywheel.

[ctrlraven]

ya my last run on a Mustang Dyno I ended up w/ 623RWHP & 588RWTQ. However this was when I still had the T-trim on the car. Now I have installed the JT-trim and I was already running short of fuel with just the dual GT fuel pumps & a mod'd FPDM. So now I needed to install a 2nd FPDM & upgrade all of the wiring to the pumps. WHile I was at it I also upgraded the fuel socks & & ran AN6 from each pump to a Yblock into AN8 to engine. this got rid of the corrigated tubing in the tank... (less pressure drop)

I fully expect to hit about 700RWHP on the Mustang dyno once this is complete. That should put me around 800HP @ flywheel.

Don't mind Glenn he is just annoyed that you are putting out that power with LT headers and not shorties.

Blown 3.8 is correct, the wiring is going to be different between a Mustang and a Marauder. I would try making sure all that wiring is correct, can you datalog the car or have an external fuel psi gauge hooked up to see exactly what it's at idle? GL!!!

[Loco1234]

my external gauge under the hood on the fuel rail says I get about 20psi at key on then it falls to nearly zero.
What is the main difference between the Mustang & the Marauder wiring...?
I have not had luck getting a hold of Jared from Lethal Performance yet... I hope to catch him this afternoon. I wanna get the vehicle back up & running...

[FordNut]

ya my last run on a Mustang Dyno I ended up w/ 623RWHP & 588RWTQ. However this was when I still had the T-trim on the car. Now I have installed the JT-trim and I was already running short of fuel with just the dual GT fuel pumps & a mod'd FPDM. So now I needed to install a 2nd FPDM & upgrade all of the wiring to the pumps. WHile I was at it I also upgraded the fuel socks & & ran AN6 from each pump to a Yblock into AN8 to engine. this got rid of the corrigated tubing in the tank... (less pressure drop)

I fully expect to hit about 700RWHP on the Mustang dyno once this is complete. That should put me around 800HP @ flywheel.

Strange... Maybe the fuel line upgrade and a BAP would have been enough. My dual GT pumps with modded FPDM and BAP carries me to 686RWHP on a Dynojet dyno.