Fitech fuel wiring

[egchewy79]

127417
I know this has been discussed in the past, but my fuse panel looks a bit different than those I've seen in the past and in the manual. I don't have that tan jumper shown in the manual. It appears my fuel pump relay (bottom of the pic) has 2 power wires. The tan one is connected to the fuel pump fuse and the orange one to the EFI/ coil fuse. Should the fitech+12v wire be powering the relay or the pump itself? Fitech directions show to the pump directly. I've also read this eliminates any issues with PWM and the relay in the fuse box, however I also understand this can be overridden with some advanced settings. What are the pros and cons of connecting the EFI power to either the fuel pump relay or directly to the fuel pump power? The inertia switch is connected to the ground, so shouldn't be in the equation, correct?

[EMO]

I have FiTech on my 33 Hot Rod. I wired mine according to the FITECH instructions, the FiTech +12v powers the fuel pump bypassing the relay in my setup and it works great. I think it will work either way, depends if you want an added relay in the circuit, or not.

[egchewy79]

What's the benefit of powering through the relay? Incorporation on the fuel pump fuse?

[phileas_fogg]

I responded on the other forum about how I wired my fuel pump using the Holley Terminator EFI system, but now I see what you mean about the RF relay.

You do in fact have a different version of the RF harness than is shown in the manual. In both versions however, RF is using a bus that is hot at RUN and CRANK to trigger the fuel pump relay. In the version shown in the manual, the relay trigger is on the +12V supply to the relay but "down stream" of the fuel pump fuse. On your fuse panel, the relay trigger is on the +12V supply to the EFI/coil "up stream" of the EFI/coil fuse. On your fuse panel, the relay feed is unprotected by a fuse; I wouldn't worry too much about that due to the very short length of wire involved. Note that if you blow the EFI/coil fuse the fuel pump will continue to work. I have no idea why RF would wire the fuse panel this way, but it will work.

If you want your FiTech to control the RF relay, cut the orange trigger wire AS CLOSE TO the spade connector on the bus as possible. That leaves a very short stub of +12V wire at the bus, minimizing your chance of it contacting something it shouldn't. Then you can use a butt connector between your FiTech & the orange trigger wire.

A better solution, if the FiTech system has its own fuel pump relay & fuse, is to de-pin the fuel pump feed where the RF main harness meets the RF rear harness. Put the appropriate weather-pak pin on your FiTech fuel pump feed, slip it into the RF main harness connector, & you're good to go. Check your FiTech manual (or call their tech support) to determine how much current their fuel pump circuit is able to support & match it to your max fuel pump current draw.

Note that this solution takes the inertia switch out of your fuel pump circuit. If you want, you can remove the inertia switch from the RF circuit and put it between your FiTech feed & the RF main harness connector. As I recall, the inertia switch is rated to 30A (but I'm going from admittedly poor memory, so if you can find the part number on the switch, look it up!), so no problem wiring it in series with your fuel pump feed if the FiTech relay is somewhere you can't get to it.

That frees up the RF tan fuel pump relay-fed circuit for some other purpose.


John

[Papa]

A better solution, if the FiTech system has its own fuel pump relay & fuse, is to de-pin the fuel pump feed where the RF main harness meets the RF rear harness. Put the appropriate weather-pak pin on your FiTech fuel pump feed, slip it into the RF main harness connector, & you're good to go. Check your FiTech manual (or call their tech support) to determine how much current their fuel pump circuit is able to support & match it to your max fuel pump current draw.

Note that this solution takes the inertia switch out of your fuel pump circuit. If you want, you can remove the inertia switch from the RF circuit and put it between your FiTech feed & the RF main harness connector. As I recall, the inertia switch is rated to 30A (but I'm going from admittedly poor memory, so if you can find the part number on the switch, look it up!), so no problem wiring it in series with your fuel pump feed if the FiTech relay is somewhere you can't get to it.


John

This is what I did for my Holley Sniper. I didn't want to cut up the RF harness to make it work with the EFI and the EFI has it's own relay and fuse, so directly connecting to the fuel pump is simple and easily reversed if you ever want to go back to the "default" setup. As stated, the inertia switch will need to be redone if you want it to be in the fuel pump circuit. Some don't like this advice, but you can put it in-line on the +12v side of the fuel pump or you can relocate it on the ground side near the pump or interrupt the ground for the ECU or EFI ground connection at it's relay. Lots of options at your disposal. I also use the RF relay for the fan circuit and as long as the fan control wire on your EFI supplies a (-) signal, you just need to tie it into either of the two RF Fan Thermo Control wires in the RF harness; one in the sending unit harness and the other in the front harness where the fan is connected.

Dave

[egchewy79]

I think I understand. Thanks all

[DadofThree]

Just to put in my 0.02; On my Fitech to RF, I skipped the relay and wired straight to the Fuel Pump RF wire. I then put the safety switch in the trunk. See attached for pics of how I wired my car. Hope it helps.

Photo 1 shows the RF harness in the left side of the photo and the right side shows the connections coming from the Fitech Unit

[egchewy79]

thanks for the pics. I think i'm going to go ahead and wire it through the existing relay so 1) I can easily replace the relay and not the ECU/EFI in the event of a wiring problem, 2)will keep the fuel pump fuse in play in the event of a problem with #1, and 3)so I won't need to move the inertia switch. I've already riveting down truck panels and getting to the wires will be a pain.