Return style wiring HOW TO allowing OE type fuel pump actuation

[MalcolmV8]

Sweet I got it guys!! I just tested it out in the garage. Primes like stock and car starts/runs ok. It's not the green wire with yellow stripe. That's nothing more than switched 12 volt with the key as I mentioned earlier. I'll write up how to wire this in a few for everyone.

 

[foxman92]

well im glad someone brought this up.. im fixing to wire up my a1000 pump, and install the relay.. so i will need to know what wire to tap into to signal the relay.. ill be following this closely.. please post results..

 

[sn94cobra]

Great job. You using the fpdm to trigger the relay?
Pin1 triggers the fpdm to send a signal out to pin 10?

 

[MalcolmV8]

SOLUTION:
OK when I first wired up my pumps return style my thought process was to remove the FPDM from the equation as it's no longer needed. Instead I took the DG/YE wire (pin 9) as everyone suggested and used it to power my relay. The downside of course is the pumps run continuously when the key is on regardless of engine running.

The signal wire from the ECC is the WH/R at the FPDM side (pin 1). It provides the correct times for the pumps to be on such as prime and then off when motor is off. It alone however is to weak to drive a relay.

So the solution is as simple as using the FPDM output that would normally drive a fuel pump to drive your relay. Use pin 10 & pin 3 to wire your relay. This way the ECC still tells the FPDM when the pumps should be turned on and the FPDM in turn activates your relay.

Pin 10 = BN/PK (normally fuel pump positive)
Pin 3 = RD/BK (normally fuel pump negative)

Note: you must use pin 3 to ground the relay coil (trigger) and not chassis ground or it does not work.

There you go guys!!
Malcolm

 

[sn94cobra]

Makes perfect sense to me. Great job staying with this.

 

[black 10th vert]

This is very exciting news, Malcolm!:beer:

 

[foxman92]

ok, so what would happen if i use my wire upgrade that i ran in the car for the dual fpdm's, 1 big ass wire from under hood thru car.. if i used that as the a power to relay, and grounded the relay to body, and then used the brown wire from harness as the trigger wire? or do i need to eliminate the ground from relay, and use both wires from fpdm harness?

 

[MalcolmV8]

I used both wires, pin 10 & 3 so the FPDM will see a complete circuit and not cause any codes to get thrown. Also I don't know the internal wiring or circuitry of the FPDM and wanted to make sure this would be reliable. You could certainly test your way and see if any codes get thrown or not.

 

[SVT GI]

Great job Malcolm!

Yeah the green w/yellow stripe is just used as a switched hot which will activate the relays full time. (just been the simplest way to wire in previously)

Do you still have your FRPS in the system? I wonder if this would still work for those that have an FRPS delete?

 

[sn94cobra]

ok, so what would happen if i use my wire upgrade that i ran in the car for the dual fpdm's, 1 big ass wire from under hood thru car.. if i used that as the a power to relay, and grounded the relay to body, and then used the brown wire from harness as the trigger wire? or do i need to eliminate the ground from relay, and use both wires from fpdm harness?

Upgrade wire to pwr feed into relay. Other side to pumps.
Ground one side of coil on relay the the other side of coil will be from fpdm pin 10.

Malcolm can confirm this. I don't have the relay pin numbers in front of me.

 

[sn94cobra]

I don't think the frps will impact this.

The fpdm I believe is nothing more than a transistor. Pin 1 trigger the fpdm to turn on and off. Pin 10 is the power feed out.
I think both wires will need to be used to get it to work correctly.

 

[foxman92]

I used both wires, pin 10 & 3 so the FPDM will see a complete circuit and not cause any codes to get thrown. Also I don't know the internal wiring or circuitry of the FPDM and wanted to make sure this would be reliable. You could certainly test your way and see if any codes get thrown or not.

ok, so your using the brown wire as the power wire or trigger? and your using the other pin as a ground? so no ground wire coming off relay to body? im just trying to visulize this lol.. so many questions.. lol

 

[sn94cobra]

I used both wires, pin 10 & 3 so the FPDM will see a complete circuit and not cause any codes to get thrown. Also I don't know the internal wiring or circuitry of the FPDM and wanted to make sure this would be reliable. You could certainly test your way and see if any codes get thrown or not.

Pin 3 is the neg from the fpdm? Hmmm. Now curious if the relay would work correctly if it was grounded vs using neg from fpdm. Can you check this both ways? Pin 3 may need to be used to complete the internal circuit of the fpdm.

 

[MalcolmV8]

Great job Malcolm!

Do you still have your FRPS in the system? I wonder if this would still work for those that have an FRPS delete?

Thanks man. Yes I do still have the FRPS. I don't know if the ECC checks it for priming or not. I have a feeling it does because mine primes fast now as though it's hitting the pressure quick (probably the dual walbro 400s). I don't know if just unplugging my FRPS would be a valid test or not? do you guys who delete it also delete it in the tune?

 

[Tims97SVT]

This thread is great!

 

[MalcolmV8]

OK I did some more testing for you guys and yes you MUST use both pins 10 & 3 to trigger your relay. If you only use pin 10 (positive) to your relay and put the ground of the relay to the frame it does NOT work. When you turn the key on the relay will trigger on and just stay on. It does not prime. Wire it as I posted in "SOLUTION" on page 2.

I should probably edit my original first post starting this tread with the solution to help others searching for this.

 

[SVT GI]

Thanks man. Yes I do still have the FRPS. I don't know if the ECC checks it for priming or not. I have a feeling it does because mine primes fast now as though it's hitting the pressure quick (probably the dual walbro 400s). I don't know if just unplugging my FRPS would be a valid test or not? do you guys who delete it also delete it in the tune?

No it's not turned off in the tune, just the fuel pump type switch and the FPDM. Let it sit for a while so the pressure can drop and unplug it and see what happens.

 

[sn94cobra]

OK I did some more testing for you guys and yes you MUST use both pins 10 & 3 to trigger your relay. If you only use pin 10 (positive) to your relay and put the ground of the relay to the frame it does NOT work. When you turn the key on the relay will trigger on and just stay on. It does not prime. Wire it as I posted in "SOLUTION" on page 2.

I should probably edit my original first post starting this tread with the solution to help others searching for this.

That makes sense for the internal circuits of the fpdm. Have you tried unplugging the frps to see if it still primes correctly?

 

[foxman92]

ok.. now the only thing you could do to make this the PERFECT thread, is to show a picture of how you have the relay wired up.. lol and thanks alot for taking the time to figure this out.. and its just in time for me to wire up my pump.. lol

 

[MalcolmV8]

No it's not turned off in the tune, just the fuel pump type switch and the FPDM. Let it sit for a while so the pressure can drop and unplug it and see what happens.

OK will do shortly.

Have you tried unplugging the frps to see if it still primes correctly?

Not yet, coming up shortly.