Gen 2 coyote fuel pump wiring

[JohnK]

Hey all,

Sorry - I know this has been discussed before but it sounds like the RF panel has had changes over time, and some versions of the FF instructions have also not been correct so I wanted to double-check before cutting any wiring for the fuel pump.

Here's what my RF panel looks like:

https://thefactoryfiveforum.com/attachment.php?attachmentid=153141&d=1631054628

https://thefactoryfiveforum.com/attachment.php?attachmentid=153140&d=1631054628

and here are the instructions as posted on the Factory Five website:

https://thefactoryfiveforum.com/attachment.php?attachmentid=153139&d=1631054628

Is this correct, and will wiring it this way preserve the inertia switch functionality?

Thanks,
John

[weendoggy]

I'm not a huge fan of cutting wires "next" to the buss bar. Cut it midway and leave a pigtail, heat shrink the end, and save it for future use. No harm, no foul.

[JohnK]

I've been doing some more reading and researching, and came across this thread:

https://thefactoryfiveforum.com/showthread.php?32593-EFI-Fuel-Pump-Wiring-Question

Alphamacaroon's photo in the first post of that thread looks to be identical to my fuse panel. Edwardb's advice in that thread was as follows:

"For this most recent RF revision, I would cut both the orange wire from the EFI and COIL fuse and the brown wire from the fuel pump fuse, and attach both to the Coyote fuel pump wire. Now you have RF power source out of the circuit, Coyote PCM/PDB providing power and controlling, and the inertia relay still in play. Hope that makes sense."

This makes sense to me, as it eliminates redundant fuses and lets the coyote PCM/PDB handle power and control. My follow-up question is - if I followed these instructions, I'm assuming that this frees up two additional circuits in the RF fuse panel (15A fuel pump circuit and 15A EFI/coil circuit) that can be used for other things, correct? So in my photo above, I would cut the two short jumper wires (orange and brown) and connect the relay side of both of those wires (the left-hand side in the photo) to the coyote fuel pump wire, and then use the right-hand side of those wires for other loads?

[Al_C]

This is a partial answer, because I can't find (without sticking my head under the dash, but doing the requisite paper search) a more complete answer... Yes, the coyote pigtail has a connection that interrupts the RF fuel pump circuit. You want the PCM controlling the fuel pump, so you will connect the pigtail wire (green?) to the wire headed for the pump in the rear wire bundle. You also will manage to keep the inertia switch intact with this approach. I believe there is only one wire involved. If my memory serves me correctly (better than 50% of the time...), the FFR instructions are good. Hopefully I get effort points if I didn't answer the question completely...

[edwardb]

OK, this gets a little confusing because of the different RF panel versions. You have what appears to be the latest version. Same as the one I just wired last week for the LS fuel pump in my truck build. Exactly the same setup.

First, theory just so we're on the same page for how this works. The orange wire is going to the coil of the relay. On the other side is the black ground wire. This wire is routed through the intertia switch. When it's closed, +12V on the relay coil and power goes to the fuel pump through the large brown wire on the RH side of the relay (per your picture). Inertia switch opens, ground is broken, relay opens, fuel pump doesn't get power. So you want that function to still work. The orange wire is powered through the EFI/COIL circuit and fuse. The brown wire to the fuel pump is powered through the 15 amp fuel pump circuit. Not to confuse the issue, but this is the change from the past. Previously, both were powered by the fuel pump circuit. Which is reflected in some of my previous answers.

So, the Coyote control pack fuel pump wire has +12V when the Coyote PCM calls for the fuel pump to run. You have three choices to wire: (1) Connect it to the orange relay trigger wire coming from the EFI/COIL circuit cut at the RF fuse location. That's what the Factory Five instructions you reference show. Result: Both panels are active. RF panel is carrying the load for the fuel pump. +12V from the Coyote will close the relay and the fuel pump will run if the inertia switch is closed. (2) Connect it to the brown wire coming from the fuel pump circuit cut at the RF fuel pump fuse location. Result: Coyote PDB carries the load for the fuel pump. RF fuel pump fuse can be removed. Inertia switch still works as described. EFI/COIL circuit still powers the relay coil, but since it's not the only thing on the circuit, OK IMO. (3) Cut and connect to both orange and brown wires. That way the Coyote PDB carries the load for the fuel pump and the relay coil. Inertia switch can still break the ground to stop the pump. Again, this is how it used to work.

My choice and how I just wired my truck? Option #2. A case could be made for any, including obviously how Factory Five shows. Based on the current RF panel wiring, I'd probably recommend against option #3. Unlike previous posts.

Hope that all makes sense.


My follow-up question is - if I followed these instructions, I'm assuming that this frees up two additional circuits in the RF fuse panel (15A fuel pump circuit and 15A EFI/coil circuit) that can be used for other things, correct? So in my photo above, I would cut the two short jumper wires (orange and brown) and connect the relay side of both of those wires (the left-hand side in the photo) to the coyote fuel pump wire, and then use the right-hand side of those wires for other loads?

Hopefully based on my explanation you'll agree that this isn't quite correct. The EFI/COIL circuit already has another wire in the harness attached to it. Not just the fuel pump relay. So it's available regardless of which of these options you choose. The fuel pump relay and fuel pump wiring in the RF harness are being used for the fuel pump in some manner regardless of option. So it's not available for anything else.

[JohnK]

Hi Paul,

Thank you so much for the very detailed response. Everything you described makes sense, and option 2 sounds like a good way to go. The only part that I still have a question on is your last statement. Earlier in your reply where you explain option 2 you state "(2) Connect it to the brown wire coming from the fuel pump circuit cut at the RF fuel pump fuse location. Result: Coyote PDB carries the load for the fuel pump. RF fuel pump fuse can be removed." However, in the last part of your reply you say "The fuel pump relay and fuel pump wiring in the RF harness are being used for the fuel pump in some manner regardless of option. So it's not available for anything else." I understand that the fuel pump relay continues to be used, but if I go with option 2 (or 3) then the fuel pump fuse is not used, correct? In other words, if I cut the brown jumper wire that runs from the fuel pump fuse to the fuel pump relay as you describe in option 2 and connect the coyote wire to that jumper, then the other part of that jumper (the part that was coming from the fuel pump fuse) could now be used for another load, rather than simply removing the fuel pump fuse. The only key difference would be that input side of the fuel pump circuit is a red wire (appears to be coming from the running lights or brake lights area of the fuse panel) so that circuit would now be battery fed rather than ignition switched.

Am I misunderstanding something?

Thanks,
John

[edwardb]

Hi Paul,

Thank you so much for the very detailed response. Everything you described makes sense, and option 2 sounds like a good way to go. The only part that I still have a question on is your last statement. Earlier in your reply where you explain option 2 you state "(2) Connect it to the brown wire coming from the fuel pump circuit cut at the RF fuel pump fuse location. Result: Coyote PDB carries the load for the fuel pump. RF fuel pump fuse can be removed." However, in the last part of your reply you say "The fuel pump relay and fuel pump wiring in the RF harness are being used for the fuel pump in some manner regardless of option. So it's not available for anything else." I understand that the fuel pump relay continues to be used, but if I go with option 2 (or 3) then the fuel pump fuse is not used, correct? In other words, if I cut the brown jumper wire that runs from the fuel pump fuse to the fuel pump relay as you describe in option 2 and connect the coyote wire to that jumper, then the other part of that jumper (the part that was coming from the fuel pump fuse) could now be used for another load, rather than simply removing the fuel pump fuse. The only key difference would be that input side of the fuel pump circuit is a red wire (appears to be coming from the running lights or brake lights area of the fuse panel) so that circuit would now be battery fed rather than ignition switched.

Am I misunderstanding something?

Thanks,
John

I normally cut the wire from the fuse right at the base where it goes into the fuse connector. Gives a longer tail to attach to and does render that circuit inoperable so just remove the fuse. I've never tried to re-use that position because I've always been able to find enough circuits or add them through other means. Which is why I answered that way. However, if you cut the wire somewhere away from the base and leave enough length, yes you could re-use that fuse position and resulting circuit. Just to be 100% clear -- if you cut leaving length on both sides, the portion of the wire going to the relay would get the Coyote fuel pump wire (option 2). The portion remaining at the fuse terminal would get a wire attached and could be routed to whatever circuit you want to use it for. Just be mindful of the load. That's a 15 amp fuse. You may have to adjust it if the load is different. Especially if you put a light load on it. The source of the +12V for that particular circuit is not affected. It would be a battery (always on) circuit as you described. The unmodified fuel pump circuit is kind of a mixed bag. The relay trigger is coming from an ignition circuit (EFI/COIL) and the actual pump power is coming from a battery circuit. So technically, the key has to be on for the pump to run. That wouldn't change with option 2.