FiTech EFI Tuning Forum

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Orange wire fuel pump

I would highly suggest anyone who is the process installing a Fi Tech system to wire the orange wire to a relay or not use it at all. Had mine wired to my fuel pump and fried my computer after 3 start ups. Been running my pump off a switched battery source so far so good.

What pump are you running?

Quantum 340 lph fuel pump

Never worked with that brand.  I have used Delco, Aeromotive and Fitech pumps.  Haven't had a problem with any of them.  All hooked directly to the Orange wire.

Fitech informed me I should not need a relay for the fcc. This was after I melted the orange wire going to it.

Put one in anyway.. no more over heated wire.

They have changed things so it is most likely not a problem now.

If you run a relay to the fcc, your pressure will be too high.

If you don't already have a fuel pressure gauge installed at your fitech fuel inlet, I would do that immediately, and make sure the pressure is within spec, if not, you will have to do what I did and put in an external pressure regulator with return line and block off the return on your fitech.  I was able to dial in my fuel pressure right at 59 psi.  My 100 psi 100 gal/hr fuel pump from Summit could not use PWM, so I had to keep it running continually with the key on.  Sounds like you're nearly there.  Good luck.

7.4 4x4 has reacted to this post.
7.4 4x4

I know this is an old thread, not sure if I should start a new one or try to revive this one.  So I'll start here and see if I get any bites.  In going through the wiring on a previous owner's installation, I was shocked to see the gauge of  the orange wire.  So I looked up the instructions and it does, in fact say to run that wire directly to the fuel pump with no relay (no fuse mentioned, either).  Maybe things have changed, but it would seem that a fuel pump would need a lot more amperage than could be safely supplied by what looks like a 16-ga wire.  And safety would seem to dictate that you run a relay or at the very least a fuse to the pump, since it is a pretty long run from the FiTech to the frame mounted pump, or even the tank mounted pump.

To appease my desire to redo and overdo everything, can anyone give me a reason not to increase that to about a 12-14 gauge wire from the connector to the pump and add a 25 amp fuse, as the pump manufacturer recommends? (Bosch 044 pump which pulls a 13 amp max...13 amps x16 ga wire x 20 ft run...should be about a 10 ga wire, by my book.  That's with a 3% voltage drop) With the lead from the unit to the connector being short, I don't think there's an issue with running that small distance with a smaller gauge wire.  I'm assuming the ECM runs the pump through PWM to adjust the output, am I right?    I eventually will go to a submerged pump when this one gives up the ghost, but for now I can't say I've had any issues with pressure at the throttle body.

Along the lines of wiring, I also was wondering if the ECM runs better at a higher in should I connect it to the junction block where the voltage is maintained at about 14.2 with the engine running, or the battery, where it's more like 12.5?

Thanks in advance, I've always gotten good info from here, I know there's some real experts who frequent these boards!

Interesting because I have wondered the same. Look at my recent post in regards to the 6-pin connector. I believe they have replaced it with a 4+2 connector, where the +2 includes the red and orange wires. Definitely,  the connector they originally used was underdesigned to handle power to the pump. If you have concerns with the orange wire, the same would be for the red wire because the power to the pump goes through the red to the ECU and then back through the orange.

1971 Mach 1 Mustang w/Ram Air, 408-4V stroked Cleveland, Hooker headers, FiTech EFI w/ RobBMC PowerSurge pump

Checked that thread and replied over there.  Sounds just on topic.