Return style wiring HOW TO allowing OE type fuel pump actuation

Termn804

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Has anyone used the green/yellow wire to power the relay instead of running a power wire from the battery?


 
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01yellercobra

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Has anyone used the green/yellow wire to power the relay instead of running a power wire from the battery?


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Do you mean to trigger the relay or power the pumps? I wouldn't power the pumps with it myself.
 

Termn804

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Do you mean to trigger the relay or power the pumps? I wouldn't power the pumps with it myself.

Using green/yellow wire for post 30 to power the relay. Pin 3 to ground the relay(Post 85). Pin 10 to trigger the relay (Post 86) then Post 87 will be going to remote one on the FC3 controller. The FC3 will be powering the pumps




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01yellercobra

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Using green/yellow wire for post 30 to power the relay. Pin 3 to ground the relay(Post 85). Pin 10 to trigger the relay (Post 86) then Post 87 will be going to remote one on the FC3 controller. The FC3 will be powering the pumps




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Wait, why are you using a relay to turn on a relay? If you have the FC3 just wire that per the instructions.
 

MG0h3

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Yes, you use pins 3/10 to trigger a relay for OE pump operation.

It should be laid out in the first couple posts.

You don’t need the FC3 as it’s just a packaged pair of relays. Them calling it a controller is misleading.

I bought my setup from the OP of this thread and he suggested saving the $175 if I was comfortable wiring.

I am so I just used three $7 relays. One has pins 3/10 so it triggers fuel pump 1 relay. The other two are actually for the pumps.


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01yellercobra

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I was trying to get it to work like OE. Although it seems like most guys just use the green/yellow wire and plug it into the controller.


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If you already have the FC3 just wire it like you would the normal relay. As MGoh3 said, it's just relays in a pretty package. No need for another relay.
 

MalcolmV8

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If you already have the FC3 just wire it like you would the normal relay. As MGoh3 said, it's just relays in a pretty package. No need for another relay.

If you're trying to use an FC2/3 in an OEM configuration where the ECU controls the pumps you need an extra relay to invert the signal from the FPDM to the FC2/3.

The reason is the FPDM controls the pump/relay signal with a constant +12 volts and ground output that it switches.
The FC2/3 on the other hand has a constant ground and uses a switching +12 volts to activate the pumps.

So you have to use an additional relay to invert the signal. The FPDM activates the relay with pins 10/3 (switching ground). The relay in turn provides a positive +12 to the FC2/3 and triggers the pump (switching +12 volt).

As mentioned above you don't need an FC2/3 if you're comfortable with wiring. They are nothing more than packaged relays with a nice breakout of labeled pins but if you already have it and want OEM operation of key on pump prime etc. Then you need an extra relay.

I hope that helps.
Malcolm
 

65wildstang

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If you're trying to use an FC2/3 in an OEM configuration where the ECU controls the pumps you need an extra relay to invert the signal from the FPDM to the FC2/3.

The reason is the FPDM controls the pump/relay signal with a constant +12 volts and ground output that it switches.
The FC2/3 on the other hand has a constant ground and uses a switching +12 volts to activate the pumps.

So you have to use an additional relay to invert the signal. The FPDM activates the relay with pins 10/3 (switching ground). The relay in turn provides a positive +12 to the FC2/3 and triggers the pump (switching +12 volt).

As mentioned above you don't need an FC2/3 if you're comfortable with wiring. They are nothing more than packaged relays with a nice breakout of labeled pins but if you already have it and want OEM operation of key on pump prime etc. Then you need an extra relay.

I hope that helps.
Malcolm

Just tried this on my car using a multimeter and pin out. I have the MS3 pnp with the FRPS still installed. Had right at 12v on wires 3/10 but voltage never dropped off. Had right at 40psi on the regulator. Also sent you a pm Malcom. Thanks for the help and advice.


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01yellercobra

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Just tried this on my car using a multimeter and pin out. I have the MS3 pnp with the FRPS still installed. Had right at 12v on wires 3/10 but voltage never dropped off. Had right at 40psi on the regulator. Also sent you a pm Malcom. Thanks for the help and advice.


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In one of his videos he talks about how to wire the pumps to prime like stock with the MS3. At least for the plug and play. The ground wire from the relay needs to be connected to one of the wires on the FPDM plug. I don't remember which one off the top of my head. I think it's one of the first videos when he's getting the redfire up and running.
 

MG0h3

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Just tried this on my car using a multimeter and pin out. I have the MS3 pnp with the FRPS still installed. Had right at 12v on wires 3/10 but voltage never dropped off. Had right at 40psi on the regulator. Also sent you a pm Malcom. Thanks for the help and advice.


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So with one lead on pin3 and one lead on pin10, key on engine off (KOEO) you had constant power?


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65wildstang

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So with one lead on pin3 and one lead on pin10, key on engine off (KOEO) you had constant power?


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Yes. With engine off I lost the 12v. Let the pumps cycle for a bit and voltage stayed constant. I believe it’s due to the ms3 and will need a ground output. I’ve briefly discussed this with Malcolm. I believe he has a video in the works for this on how he made it work with PNP. He’s been great with responding on some other issues and a big help. I have some ideas how I can do this manually with a relay until I’m more knowledgeable on the software. Thanks


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01yellercobra

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This is actually on my list of things to do. Every time I get motivated something else pops up though. It would be nice not to have the pumps running while I'm downloading logs.
 

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