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:
<iframe width=100% height=560px frameborder=0 src=http://docs.google.com/gview?a=v&pid=explorer&chrome=false&api=true&embedded=true&srcid=0BypLo0rFWNp7ZGU0ZjNlYmI tMDU1Ny00OTZhLTg4ZTYtNTkzNWU5Z jFiMzY2&hl=en></iframe>
http://docs.google.com/leaf?id=0BypLo0rFWNp7ZGU0ZjNlY mItMDU1Ny00OTZhLTg4ZTYtNTkzNWU 5ZjFiMzY2&sort=name&layout=list&num=50
http://docs.google.com/leaf?id=0BypLo0rFWNp7ZGU0ZjNlY mItMDU1Ny00OTZhLTg4ZTYtNTkzNWU 5ZjFiMzY2&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. :lol:

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.

[Glenn]

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.

WOW! - yes, you need the dual GT pump. Good Luck.

Glenn

[Blown3.8]

Here is a mustang diagram. From this site http://www.innovativesitedesign.com/03cobratech/images/fuelpump/dual_FPDM_wiring.jpg
http://i169.photobucket.com/albums/u216/blown38/dual_FPDM_wiring.jpg
The green/yellow on marauder = light blue/orange in pic
blue orange on marauder = white/red in pic
pink/brown = brown/pink
brown/white = red/black
black = black Ground for fpdm
white = dark green/yellow
inertia switch = ccrm
Add your BAP's after relays and adjust fuses accordingly

[Loco1234]

Here is a mustang diagram. From this site http://www.innovativesitedesign.com/03cobratech/images/fuelpump/dual_FPDM_wiring.jpg
http://i169.photobucket.com/albums/u216/blown38/dual_FPDM_wiring.jpg
The green/yellow on marauder = light blue/orange in pic
blue orange on marauder = white/red in pic
pink/brown = brown/pink
brown/white = red/black
black = black Ground for fpdm
white = dark green/yellow
inertia switch = ccrm
Add your BAP's after relays and adjust fuses accordingly

Thank you. I found thisd on the internet last night too. I also had Lethal Performance send me a pin diagram. (attached) I plan to go through all of the wiring tonight... However after speaking with Lethal Performance I'm not sure that I'll find something wrong with the wiring but I truely hope so...
The main difference between this diagram you posted & the lethal setup is that lethal using on one (1) relay & slightly larger wire.

[Loco1234]

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.

ya I kinda wish I just did a 40amp BAP now instead of all this headache. n I figured this is the cleaner way to accomplish my fuel requirements considering that I never used to run a BAP (20amp or 40amp) & I could avoid doing so now... More like "Ford" intended or would do it..

It would seem that I may have the 1st Marauder to do a Dual GT fuel pump & Dual FPDM setup. (1 FPDM mod'd)
THis site, Lethal Performance & Dennis R have all confirmed that this is the 1st Marauder they know of do so...
Great Im the 1st to do it & it isn't work "ATM" I will not rest till this is sorted out... Anyone wanna road trip to North East PA & curse at this w/ me...?

[Zack]

I had to chime in so you wouldnt keep wasting time and money.

Shermanator has this mod done, as well as merc's car (i think)

I would bet the biggest problem you have is the placement of the actual pumps on the stock Marauder Fuel Hat assembly. Ive seen 2 early Dual Pump assemblies either bent or the pumps welded on so the socks are sitting, SQUASHED on the bottom of the tank. I chased this problem in my car for 3 M**** years before i took the tank out, and looked at everything through the filler neck hole. You guessed it, the entire assembly was built wrong.

[Loco1234]

I had to chime in so you wouldnt keep wasting time and money.

Shermanator has this mod done, as well as merc's car (i think)

I would bet the biggest problem you have is the placement of the actual pumps on the stock Marauder Fuel Hat assembly. Ive seen 2 early Dual Pump assemblies either bent or the pumps welded on so the socks are sitting, SQUASHED on the bottom of the tank. I chased this problem in my car for 3 M**** years before i took the tank out, and looked at everything through the filler neck hole. You guessed it, the entire assembly was built wrong.

Perhaps Sherm or Merc can chime in to assist. I guess they didn't use Dennis or lethal Performance for the mod... cuz Niether said they have done a Marauder w/ this setup.

Zack you actually did the original dual cobra pumps & the fuel hat mod (welding) for dual pumps on this car. I simply re-used the same hat with the dual GT pumps. Granted I now drilled it & utilizing bulk head fittings (like we discussed months ago) but do you think it could just be thew socks are squashed? I didn't have this fuel problem before with the GT pumps.. I ran them for about a year now. I did just take them out & put them back in with the bulkhead fittings done however... I get about 20psi when I turn key but then it drops off to just enough for idle but it can't rev at all... I figured if it were simply squashed socks I'd be able to get a bit above idle but not enough fuel for the dyno...

[Loco1234]

http://www.innovativesitedesign.com/03cobratech/gt40pumpupgrade.html

Can anyone better explain to me what step 12 & 13 are instructing to be done... I bought the entire wiring harness pre-built so now I gotta go back through it & never did these steps myself.

[justbob]

If it helps any here, I installed a smaller sock for a GM. I can't remember for sure, but I wanna say it was for the 97 and older aero model. Anyways, MUCH smaller, and close to center outlet. I bought it at advance auto. Hope this helps.

[Loco1234]

If it helps any here, I installed a smaller sock for a GM. I can't remember for sure, but I wanna say it was for the 97 and older aero model. Anyways, MUCH smaller, and close to center outlet. I bought it at advance auto. Hope this helps.

I did just upgrade w/ new larger sock's from Lethal Performance as part of this round of fuel upgrades. They are approx 1/3 longer then the previous fuel socks and look like they will flow much better...

[merc]

Perhaps Sherm or Merc can chime in to assist.

I hate to bring you the bad news but you are not the first to run dual fpdm's, dual KB boost pumps, and dual GT fuel pumps. Sherman had this setup 2.5 years ago, and I have run the same configuration for the last year. The common denominator is Blown38. He has done both installs and they are track proven. From what I read you need to change your fuel system to a return style. 700+ hp makes allot of demands on a car.

If you use a Y to join the 2 fuel pumps internally you may have a problem I experienced. The issue was one KB boost pump fuse failed and only one GT fuel pump was working. The pump was sending fuel to the Y and flowing back to the second none functional pump. It took us a while to figure out the cause of the fuel pressure problem. The failed boost pump was the 20 amp version supplied by Trilogy. We added a 40 amp fuse and life was good. What is odd or not explained is why the 20 amp fuse failed.

[justbob]

I was worried about the size being alot smaller at first but dyno confirmed PLENTY of fuel with my set up being only a single Walbro and a BAP turned way down. I know that you are in a different league by far, just saying that size didn't change anything at all for me. It was all they had with a stock size hole in stock and my car was all apart so I decided to try it. It was a tad bigger than half the size of stock.

[Zack]

Zack you actually did the original dual cobra pumps & the fuel hat mod (welding) for dual pumps on this car. I simply re-used the same hat with the dual GT pumps.

I didnt make the modifications to the pump hat....it was bought from DR and made by Pauls High performance.

As I said, Ive seen them made wrong where the pumps are squashed against the bottom of the tank. All is well until above 4500 then FP goes way down.

In addition, both assemblies i had shipped to me were in flimsy boxes with no packing around them and they can be bent very easily if dropped.

IMHO you are wasting your time and money staying returnless. The less demands you put on the PCM at your power level, combined with an automatic trans the better.
Sump the tank, put twin Bosch 044's on it and call it a day.

[pacammer]

I hate to bring you the bad news but you are not the first to run dual fpdm's, dual KB boost pumps, and dual GT fuel pumps. Sherman had this setup 2.5 years ago, and I have run the same configuration for the last year. The common denominator is Blown38. He has done both installs and they are track proven. From what I read you need to change your fuel system to a return style. 700+ hp makes allot of demands on a car.

If you use a Y to join the 2 fuel pumps internally you may have a problem I experienced. The issue was one KB boost pump fuse failed and only one GT fuel pump was working. The pump was sending fuel to the Y and flowing back to the second none functional pump. It took us a while to figure out the cause of the fuel pressure problem. The failed boost pump was the 20 amp version supplied by Trilogy. We added a 40 amp fuse and life was good. What is odd or not explained is why the 20 amp fuse failed.

Thats good news that Im not the 1st... This way I know its not impossible... Im still not sure y its not working however... i just went through ever wire one by & confirmed them to all be correct as blown3.8 stated on page one...
The blue wire does go to both FPDM's the green only is wired to one FPDM...
If I wasn't already bald I be loosing my hair at this point...

[Loco1234]

OK well tonight I plan to pull the fuel hat back out of the fuel tank... I simply don't get it... I'm hoping there's some simple explanation like a wire fell off while installing in tank... or the fuel socks really are touching the bottom of the tank... however I don't think so... Perhaps with it out I can do some more troubleshooting... any suggestions...?

[Loco1234]

Ok last night I took the entire fuel hat & pumps back out of car... I checked the socks, wires etc... I reconnected all of them... but all seemed fine... and it made no difference at all...
I think tonight I'm gonna try & hook it back up the way it was but using the new larger guage wires running through the fuel hat since I pulled the old (now unused ones) out... I hope to get the car good to drive around daily again and look into this as I have more time... I gotta get this car back on the road...

I even tried to re-pin the bl/or & the gr/xx wire by switching them... no result... I observed the pumps push fuel out of the Y-block into a bucket but once again only at key on...

[Loco1234]

OK now something is really not right... I removed the dual wiring kit & I tried to setup the furl system as it was before I started... This is 1 FPDM, stock wiring & dual GT fuel pumps... The only part of the fuel system I didn't convert back to how it was before is the last 10" of wiring going through the fuel hat & on to the fuel pumps themselves. I used the stock wiring (pink w/ blk stripe & brown w/ yel stripe to power the pumps. I simply put spade connectors on the ends of the wiring so I can easily switch between the new wiring & the one wiring...
I still habve the same problem. No fuel pressure & the only fuel that flows is a key on. But if I disconnect the fuel line I do get fuel coming out for a momnet when the key is turned... Anyone have any further Ideas.. It would seem that it's failure to work has nothing to do with the new setup & wiring vs the old setup & wiring.

I did however leave the new bulkhead fittings & billet alum Y-block installed as opposed to the stock arrangement. but this does seem like a wiring problem not having to do w/ fuel flow in the lines... so I don't see a problem there..

Does anyone have or can they get the current the dual GT pump arrangement draws at key on, idle & when the gas is stepped on... It would help me further toubleshoot. The voltage readings would also help...

[Zack]

OK now something is really not right... I removed the dual wiring kit & I tried to setup the furl system as it was before I started... This is 1 FPDM, stock wiring & dual GT fuel pumps... The only part of the fuel system I didn't convert back to how it was before is the last 10" of wiring going through the fuel hat & on to the fuel pumps themselves. I used the stock wiring (pink w/ blk stripe & brown w/ yel stripe to power the pumps. I simply put spade connectors on the ends of the wiring so I can easily switch between the new wiring & the one wiring...
I still habve the same problem. No fuel pressure & the only fuel that flows is a key on. But if I disconnect the fuel line I do get fuel coming out for a momnet when the key is turned... Anyone have any further Ideas.. It would seem that it's failure to work has nothing to do with the new setup & wiring vs the old setup & wiring.

I did however leave the new bulkhead fittings & billet alum Y-block installed as opposed to the stock arrangement. but this does seem like a wiring problem not having to do w/ fuel flow in the lines... so I don't see a problem there..

Does anyone have or can they get the current the dual GT pump arrangement draws at key on, idle & when the gas is stepped on... It would help me further toubleshoot. The voltage readings would also help...

Did you put a check valve anywhere in the system? If so thats the problem.

[Loco1234]

Did you put a check valve anywhere in the system? If so thats the problem.

We did remove the valve (white device) that was installed inside the fuel tank with the fuel drain back line on it.. That was not reused. I was under the impression that it was not required and would only prevent the car from having to refill the fuel lines when the car was gonna be started... (hence may create rougher starts) and it also does something when you got off of the throttle quickly...

If not Im sure it can be reinstalled... however currently each fuel pump run straight through their own bulkhead fittings & to the Y-Block.

[FordNut]

I did the opposite and put one of the check valves on each pump.

[Loco1234]

I did the opposite and put one of the check valves on each pump.

but are they required or are they just to reduce cranking time till engine starts?

[FordNut]

The check valve has two functions. One is to keep fuel from draining out of the fuel line and going back into the tank. That is the starting issue. The other is to function as a pressure relief valve and prevent excessive pressure.

[Loco1234]

The check valve has two functions. One is to keep fuel from draining out of the fuel line and going back into the tank. That is the starting issue. The other is to function as a pressure relief valve and prevent excessive pressure.

Thanks, that is what I thought but it won't cause the fuel pressure problems I have experienced...(will it?) I'm really between a rock & a hard place. I was told by Lethal Performance that it may be the Fuel Pressure sensor at the rail. I know we haven't had a problem with the fuel pressure sensor in the past nor did we change it at all...

[merc]

I know we haven't had a problem with the fuel pressure sensor in the past nor did we change it at all...

I replaced my fuel pressure sensor 4 times a year. Go with a return system and call it a day. :D

[martyo]

I replaced my fuel pressure sensor 4 times a year. Go with a return system and call it a day. :D


The big boys run a returning fuel system.

Just sayin'.

[merc]

The big boys run a returning fuel system.

Just sayin'.

Your seats are in my living room. After I get my car together, a new return system is what I will do. Watch Pinks all out this Thursdays, hint hint.

[Loco1234]

Ya Zack Suggested to do a return system as well. But now I can't get it to even run how it was before I started the conversion to Dual FPDM's...
I gotta get it back up & running be fore I start to make more changes... I wanna make sure I solve 1 problem before creating the next headache...

Does anyone have the amps/volts as seen by fuel pump 1 & 2 during key on, idle & under average load... lets say 3500rom in park... I wanna see if the pumps are getting the signal they should be... They are getting the approx 10.5 volts they are supposed to see w/o a BAP.

[FordNut]

Thanks, that is what I thought but it won't cause the fuel pressure problems I have experienced...(will it?) I'm really between a rock & a hard place. I was told by Lethal Performance that it may be the Fuel Pressure sensor at the rail. I know we haven't had a problem with the fuel pressure sensor in the past nor did we change it at all...

Pulling out the check valve/pressure limiter may have caused you to blow one.


I replaced my fuel pressure sensor 4 times a year. Go with a return system and call it a day. :D

I've never blown one.

It's all in the tune.

[frdwrnch]

Here is a logic chart of the pcm fuel pump duty cycle. It uses tables based on feedback from the FRP sensor and FPM circuits to calculate this duty cycle. Note that a 50% duty cycle is 100% on. I am not sure if this is pin 40 or pin 80 of the pcm. I also am not sure what the reference voltage is supposed to be on this circuit at any rpm. If your out of this range the fuel pump runs at 25% duty cycle which could account for your problem.
Here is the chart:
TABLE 2—FUEL PUMP DUTY CYCLE OUTPUT FROM PCM

FP Duty Cycle Command PCM Status FPDM Actions
0-4% PCM will not output this duty cycle. Invalid FP duty cycle. FPDM will send 25% duty cycle signal on the fuel pump monitor (FPM) circuit. The fuel pump will be off.
4-5% Dead band range for transitions between FPDM states. —
5-45% Normal operation. FPDM will operate the fuel pump at the speed requested. "FP duty cycle" x 2 = pump speed % of full on. (for example FP duty cycle = 42%. 42x2=84. Pump is run at 84% of full on). FPDM will send 50% duty cycle signal on FPM circuit.
45-48% Normal operation. An open circuit cannot be detected in this range. FPDM will operate the fuel pump at the speed requested. "FP duty cycle" x 2 = pump speed % of full on. FPDM will send 50% duty cycle signal on FPM circuit.
48-51% Normal operation. FPDM will operate the fuel pump at full on. FPDM will send 50% duty cycle signal on FPM circuit.
51-52% Dead band range for transitions between FPDM states. —
52-68% PCM will not output this duty cycle. Invalid FP duty cycle. FPDM will send 25% duty cycle signal on the FPM circuit. The fuel pump will be off.
68-70% Dead band range for transitions between FPDM states. —
70-81% To request the fuel pump off, the PCM will output this duty cycle. Valid fuel pump off command from PCM. FPDM will not operate the fuel pump. FPDM will send a 50% duty cycle signal on the FPM circuit.
81-83% Dead band range for transitions between FPDM states. —
83-100% PCM will not output this duty cycle. Invalid FP duty cycle. FPDM will send 25% duty cycle signal on the FPM circuit. The fuel pump will be off.

NOTE: Also refer to PCM Inputs, Fuel Pump Monitor and Powertrain Control Hardware, Fuel Pump Driver Module.


Hope this helps

[Blown3.8]

Have no problems here with removing the check valve on Sherm's or Merc's car. Just the harder start.

[Blown3.8]

But if one is not running the car won't run as it pushes fuel back thru the non running pump. Which if it was setup like Fordnut has the car would still run if one pump went down.

[Loco1234]

Pulling out the check valve/pressure limiter may have caused you to blow one.



I've never blown one.

It's all in the tune.

I spoke with Zack briefly on the phone last night & he said even with the fuel rail pressure sensor removed it should still run. & I haven't gotten the pumps to supply m ore than 10psi & that's only at key on... so I doubt it is blown out...

[Zack]

You made no mention of running the new power wires through the Fuel Hat. Maybe Im mistaken, but if thats the case you have 2 FPDM's trying to control the same 2 pumps.

I really dont think thats possible to even do.

[Loco1234]

You made no mention of running the new power wires through the Fuel Hat. Maybe Im mistaken, but if thats the case you have 2 FPDM's trying to control the same 2 pumps.

I really dont think thats possible to even do.

Yes each GT fuel pump has its own FPDM.

[Loco1234]

Here is a mustang diagram. From this site http://www.innovativesitedesign.com/03cobratech/images/fuelpump/dual_FPDM_wiring.jpg
http://i169.photobucket.com/albums/u216/blown38/dual_FPDM_wiring.jpg
The green/yellow on marauder = light blue/orange in pic
blue orange on marauder = white/red in pic
pink/brown = brown/pink
brown/white = red/black
black = black Ground for fpdm
white = dark green/yellow
inertia switch = ccrm
Add your BAP's after relays and adjust fuses accordingly



ZACK the setup is very similar to what you see here.. only there is only one relay to power both FPDM's... but I decided to utilize an 8guage power wire & fuse holder from the trunk mounted battery...

[Blown3.8]

Put 2 relays in, you maybe overloading the one as they are rated at 30 amps. I have 2 seperate power wires to each relay then to each BAP to each FPDM. The relay trigger wire is common to both relays tho, just jumped off of one to the other. Do you have 4 power/ground wires going thru the hat to the pumps?

[Blown3.8]

Heres a pic.

[Loco1234]

Put 2 relays in, you maybe overloading the one as they are rated at 30 amps. I have 2 seperate power wires to each relay then to each BAP to each FPDM. The relay trigger wire is common to both relays tho, just jumped off of one to the other. Do you have 4 power/ground wires going thru the hat to the pumps?

The Lethal performance kit only comes with 1 relay & they sell them like that all the time... so Im not sure thats it but I am willing to try almost anything at this point... Yes I have 2 red 12guage wires & 2 black 12guage wires. 4 wires in total going to the fuel pumps. each fpdm is wired to its own fuel pump.

[Loco1234]

file:///C:/Users/GTRAVI%7E1.GTA/AppData/Local/Temp/moz-screenshot.pngfile:///C:/Users/GTRAVI%7E1.GTA/AppData/Local/Temp/moz-screenshot-1.pngWithout taking a photo of my cars truck & posting it... "Which I should & will..."
here:
<iframe width=100% height=560px frameborder=0 src=http://docs.google.com/gview?a=v&pid=explorer&chrome=false&api=true&embedded=true&srcid=0BypLo0rFWNp7ZGU0ZjNlYmI tMDU1Ny00OTZhLTg4ZTYtNTkzNWU5Z jFiMzY2&hl=en></iframe>

or

http://docs.google.com/leaf?id=0BypLo0rFWNp7ZGU0ZjNlY mItMDU1Ny00OTZhLTg4ZTYtNTkzNWU 5ZjFiMzY2&sort=name&layout=list&num=50

[Zack]

Did you hook 12 volts to the pumps individually yet and check for fuel flow?
Best to get the mechanical problems ruled out first.

[Loco1234]

Did you hook 12 volts to the pumps individually yet and check for fuel flow?
Best to get the mechanical problems ruled out first.

That's gonna be the next thing we try... but dont the GT fuel pumps ramp up based off of Current not voltage? I kinda thought most returnless system pumps work this way... Hence the FPDM... Kinda like a ballast is to a light bulb...

[FordNut]

The GT pumps run the same as the Cobra pumps as well as the OEM pump. Virtually all returnless systems control the pumps with a pulsed control signal. The PCM outputs low current pulses (I believe they are also low voltage, maybe 5V) at a rate determined by the desired fuel pressure (in the program or tune) compared to the actual fuel pressure measured by the FRPS.

The low current pulses are fed to the FPDM where they are converted to high current 12 volt pulses which drive the fuel pumps. Depending on the frequency, the output of the FPDM may measure virtually anything up to 12 volts when checked with a DC voltmeter.

If you add a BAP, what it does is boost the power supply voltage to the FPDM. In that case the output voltage of the FPDM may be as high as 17 volts.

[Loco1234]

The GT pumps run the same as the Cobra pumps as well as the OEM pump. Virtually all returnless systems control the pumps with a pulsed control signal. The PCM outputs low current pulses (I believe they are also low voltage, maybe 5V) at a rate determined by the desired fuel pressure (in the program or tune) compared to the actual fuel pressure measured by the FRPS.

The low current pulses are fed to the FPDM where they are converted to high current 12 volt pulses which drive the fuel pumps. Depending on the frequency, the output of the FPDM may measure virtually anything up to 12 volts when checked with a DC voltmeter.

If you add a BAP, what it does is boost the power supply voltage to the FPDM. In that case the output voltage of the FPDM may be as high as 17 volts.

...so will hooking 12v straight up to the Pumps be an accurate test to confirm there are no mechanical problems...or are the FPDM's req'd to proper power the pumps so they flow...

[FordNut]

Yes, a solid 12V is the same as 100% duty cycle.

[Loco1234]

Yes, a solid 12V is the same as 100% duty cycle.


awh great... I was worried that the system was like a light bulb ballast. Voltage doesn't drive it... its current (amps) thats makes it all happen...

I'll have to try that later... or tomorrow... I just got my new Qvale mangusta in Yesterday so tinkering with that new toy...

I post a new thread w/ pic about that though.. soon enough

[Loco1234]

ok I put 12v straight to the pumps & ran them in a small bucket outside the car.. I found that the AN to bulkhead fittings dont mate up & seal properly... the bulkhead fitting is a machine thread & the an is well... AN
So I miseed the parts store on Sunday before they closed... I plan to get there today & order or buy if in stock 2 adapters to connect the AN6 to the machine thread.. I need male AN6 to female machine thread.

Once this leak is over come I hope this car will come alive like Frankenstein...

Also where does are FPDM ground to chassis at?

[1stMerc]

Did this ever get resolved?

[pacammer]

Yes. It now works well. The kit contained 3/8 inch pipe thread / an 6 fittings, male x male.
These pipe thread connections were in the fuel tank. The fittings leaked inside the tank out of site and hearing range. Once we discovered the problem we swapped the fittings with an AN 3/8 tapered thread x an 6 fitting male x male our problem was solved.

The Lethal Performance kit works well with the Marauder wiring. Fits nicely next to the factory FPDM. Now to the dyno to see if we can meet and / or safely brake 700 rwh on my daily driver.

Thanks for following up on our fuel problem. I will ask loco1234 to post some pictures. The lethal kit works well as long as Eastern European hands stay far away.

Regards,
Gary