Romer

Hey

I have wired my fuel pump relay to the black and pink wire from the FPDM harnesh, but the pumps dont cut off after 3 seconds with the key in the on position and the engine off, which I believe it should?.

Which wire are you guys using?

Bpohlman13

I thought you arent supposed to hook it up to the original fuel pump harness? I thought it was supposed to be hooked upto the fuse box for when the engine is running? IDK 100% though.

Romer

The power wire goes directly to the battery, but the wire for controlling the fuel pump should be in the original wire harnesh somewhere.

cliffyk

It sounds as though you have your relay connected to the FPDM's +12V (pink with black strip) and ground (black) inputs (highlighted in yellow below), rather than to its output connections (+ = brown w/ pink stripe; - = red/black; highlighted in green below).



I believe you will have to change the Returnless fuel pump mode scalar value in the tune to 0, and make sure the Return Fuel duty cycle is set to a reasonable value (70% is shown below), to have this work properly.



This tells the PCM to run the pump all the time at 70% d/c, and will insure that the FPDM output voltage does not drop below that needed to keep your relay pulled in...

Romer

Yes, I have it hooked up to he black and pink wire, but do not have the fpdm connected.

I am not sure i fully understand what you are saying, but isn't it the ecm that controls the fuel pump on/off? As far I have read on this forum and others most people remove the fpdm from the car.

If I understand you and I connected the fpdm the brown/pink wire work with the modifications you mentioned.

oxfordgt

You have it hooked up correctly. Return style pumps never turn off.

Romer

Thx for confirming.

Do anybody use the speed controllers to slow the pumps down until needed?

cliffyk

You can use the FPDM and a relay as I indicated, and have the PCM stop it at KOEO--changing those 2 scalars will make it do that.

oxfordgt

Just leave it how you got it that is how I had mine with no problems. I had an A1000 and no need for a controller. As long as your tank is designed correctly you won't have a problem.

DrCobra

Sorry to dig up this old thread, but I'm converting an 04 GT to a return fuel system, and I just wanted to be clear on a few points. When wiring the relay for the fuel pumps, can I use the bn/pk wire to trigger the relay and ground the relay to the chassis? Or does the Rd/Bk wire need to be hooked to the ground on the relay? Can I hook this up and get the pumps to run before changing the parameters in the tune ?