So i installed gt pumps. dual fpdm's, wiring upgrade, etc. So when i turn the key to the on position the fuel pumps kick on....then they dont kick off. my fpdc is around 45-50 at idle. And then when i just slightly accelerate the fpdc maxes out at 98. Please give me some input. Thank you.
Please help, about to start breaking things.
- Thread starter Chovy03
- Start date
Go over the wiring for the dual FPDM. Did you buy a plug and play harness? Do you have a BAP?
I got another harness from an older mustang and bought a new fpdm. Wired it in myself. I do have a bap but it's not currently wired in with it all. It's in the stock hat modified. My fuel rail pressure at idle is around 39 psi.
I'm almost 99.9% sure the wiring is all correct. I studying the schematic for a long time and went slowly step by step with everything.
Really sounds like something is not wired correctly. Im willing to bet something is wired wrong keeping the pumps running not allowing the ECU to control them through the FPDM. Take a breather and go over the wiring again. Youll see its a minor mix up and youll have it fixed in no time. How are you measuring FPDC and FP?
Sct 4 and my surface tablet. Is there something specific I should be looking for? What could hinder the ecu telling them to shut off?
Your not sharing power or ground to the pumps right? Each pump needs it's own wires. The pumps are controlled via the ground power is constant. Each FPDM needs signal from the red/white wire but only one can return the blue/orange signal.
I assume your running the wire upgrade with relays providing FPDM power?
I assume your running the wire upgrade with relays providing FPDM power?
Yes that is correct. I do have the wire upgrade with relay. And no each pump has its own wires coming from its respective Fpdm. I have both fpdm connected to the red/white wire. And the master fpdm is the only one with blue/orange
Ok guys, just wanted to update everyone in case someone else encounters this problem. And, by the way, thank everyone for the responses. Turns out the pumps are ran with a constant hot wire (the brown and pink wire from fpdm) and a negative. The negative is the red and black wire. To run the pumps it makes or breaks the negative to turn them on or off. Well I had a direct short from one negative to ground. So even though the fpdm was breaking the negative, it was still staying grounded by the short. So traced the wire, found the short. And boom. No more constant pumps running. Hopefully that makes sense. Sorry if it's confusing. Not too great with explaining things. And again. Thank you all.
Yup you hit the nail on the head I was explaining this yesterday in the other thread with this issue. The fact that there is a voltage table makes people think the positive voltage is regulated when the voltage is actually an average of the on/off pulses.
Glad you solved it think the other guy is going to find the same kind of short somewhere.
Glad you solved it think the other guy is going to find the same kind of short somewhere.
Thanks man I appreciate all the input and help from people on this site. Things would be a lot harder without knowledgable people willing to help. I'll always try and return it when I'm able to.
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