Return style wiring HOW TO allowing OE type fuel pump actuation

MalcolmV8

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I'm doing a 04 Cobra swap into my 96 Cobra (Everything but the fuel stuff), and wanted to keep my tank, lines, and I have a custom 96 fuel rail (buying one) that fits the 04 intake. I'm just running one 320lph fuel pump, which is plenty for my setup. I was wondering how I would power the FP this way, and then I found this post. I really hope this works for my setup.

I don't see why it wouldn't. Simply use the FPDM to trigger your single fuel pump how its explained in the first post of this thread.
 

laddanator

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I don't see why it wouldn't. Simply use the FPDM to trigger your single fuel pump how its explained in the first post of this thread.


Thanks for the info by the way!! Can't wait to get the swap done, and post my results of the FP deal here.
 

laddanator

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MalcolmV8, I'm getting ready to wire this as you described. I assume the yellow and black on the harness run the sending unit? I'm still using my 96 tank, with a 320lph pump, so my sending unit is a separate piece, but has the yellow-black wire as does the yellow-black wire going into the 04 tank.
 

MalcolmV8

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MalcolmV8, I'm getting ready to wire this as you described. I assume the yellow and black on the harness run the sending unit? I'm still using my 96 tank, with a 320lph pump, so my sending unit is a separate piece, but has the yellow-black wire as does the yellow-black wire going into the 04 tank.

I'm confused by what wires you're referring to but the PM you sent me made much more sense. No you do not use the FPDM to supply the heavy current side of the relay to power the pumps. You need to run a heavy gauge wire (8 or 10 gauge) from the battery back to the relays for the pumps power source.
 

laddanator

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I'm confused by what wires you're referring to but the PM you sent me made much more sense. No you do not use the FPDM to supply the heavy current side of the relay to power the pumps. You need to run a heavy gauge wire (8 or 10 gauge) from the battery back to the relays for the pumps power source.


That's what I figured. I have all the interior pulled out, so this will be a easy run from the batt. Thanks!!
 

31BCobra

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Okay so I just got done reading through this thread as I plan on doing it myself. If I wire everything properly, will specific adjustments need to be made to my tune for it, or will it run alright? Assuming I wire everything correctly. I am running are Fore Level 2 with dual 465s and frps delete.
 

MalcolmV8

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Okay so I just got done reading through this thread as I plan on doing it myself. If I wire everything properly, will specific adjustments need to be made to my tune for it, or will it run alright? Assuming I wire everything correctly. I am running are Fore Level 2 with dual 465s and frps delete.

Your tuner should change your tune from returnless to return style.
 

laddanator

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I'm going to redo this to look better, but here is my plan of attack. My tuner just told me he would make it run at 15 volts at all time.


 

31BCobra

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So if I am using a fore FC2 controller, instead of a relay, then pin 10 will go to REMOTE and pin 3 will go to ground?

Picture of FC2 for reference.

23-100-4.jpg
 

MalcolmV8

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So if I am using a fore FC2 controller, instead of a relay, then pin 10 will go to REMOTE and pin 3 will go to ground?

Picture of FC2 for reference.

23-100-4.jpg

There's nothing "controller" about it. That FC2 is also just relays, just in a casing to look nice. Been a while since I've wired one of those for someone but yes I believe remote and ground go to pins 10 and 3.
 

31BCobra

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There's nothing "controller" about it. That FC2 is also just relays, just in a casing to look nice. Been a while since I've wired one of those for someone but yes I believe remote and ground go to pins 10 and 3.

Fancy word for a fancy piece. lol. Alright then, thanks for the help, I will report back with my findings in a few days.
 

laddanator

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So if I am using a fore FC2 controller, instead of a relay, then pin 10 will go to REMOTE and pin 3 will go to ground?

Picture of FC2 for reference.

23-100-4.jpg

I like the way this looks, but that thing is a 169 dollars!! No way, brother..Lol I'll just use my 4 pin relay, but that is a nice relay.
 

bigmoose

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31BCobra

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I like the way this looks, but that thing is a 169 dollars!! No way, brother..Lol I'll just use my 4 pin relay, but that is a nice relay.

Yea, I wasn't going to fork out the money for it either. But I had to buy all the trimmings to get a nice discount on the package, and it came out to be less with the relay than without it. So I went for it.
Don't ask me how that works, cause I was wondering the exact same thing. lol.
 

31BCobra

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Got everything working as intended it seems. Tested it all in a bucket with some fuel in it before cramming everything back in. Primes as intended and shuts off after about a 1 second delay. Thanks for the Help!
 

laddanator

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Got everything working as intended it seems. Tested it all in a bucket with some fuel in it before cramming everything back in. Primes as intended and shuts off after about a 1 second delay. Thanks for the Help!

I've got mine all wired up, and stuck a hose in a milk jug to catch the fuel. Turned the key, and fuel started pumping, but it didn't shut off until I turn the key back to the off position. Can't image this thing is wired wrong.

When I turn the key on, I hear relay kick on, and pump runs. It filled this much fuel into the jug, and was still going until I turn the key back. This seems to be way to much fuel. Figured it would only "prime" for a second or so.


 
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laddanator

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Ok guys, figured it out. The pin 3 ground I used, I put in on the relay as described, but then I came back out of the relay, and used that wire (split) to ground my pump. Can't do that!! Lol As said here, body ground will cause the relay to be on all the time (I guess the pump is one big body ground as it over took the FPDM pin 3 ground) , so have to use a different ground...other than the ground from pin 3...to ground the pump.
 
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MalcolmV8

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Ok guys, figured it out. The pin 3 ground I used, I put in on the relay as described, but then I came back out of the relay, and used that wire (split) to ground my pump. Can't do that!! Lol As said here, body ground will cause the relay to be on all the time (I guess the pump is one big body ground as it over took the FPDM pin 3 ground) , so have to use a different ground...other than the ground from pin 3...to ground the pump.

Pin 3 and pin 10 should only go to activate your relay. The pumps themselves should use battery supply and chassis ground.
 

lcaptmorg

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Using sct prp, have every thing wired up as per thread. Any details on tunning fr the fpdm.

Just max out fuel pump voltage and dc?
 

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