Racetronix electric fuel pump setup

[CWPottenger]

Since you do not have an original EFI car there is no harness or wires run for the pump. The sender wire is all you will have in your car. If you purchased the hot wire kit then just follow the direction to connect it up. We are just saying use a connector in the back near the tank for ease of future work, removal on tank.


From the relay.

pin 30 will go to battery( or other very good 12v source)
pin 86 will go to a key on circuit or fuel pump output of ECM
pin 85 will go to ground
pin 87 will go to 12v input of fuel pump

Pump side
12v power to pin 87
ground to a clean chassis ground
fuel level to sender wire

 

[DoubleV]

I get how the wires are supposed to hook up, but I'm not seeing how YOU were able to do it the way you did. If your car was a carbed car from the factory as is mine, then all you should have in your car is a single pink fuel gauge wire yet it seems you have the grey 12v power wire on yours you were able use. Since I have no factory grey 12v wire in the rear, I have nothing to use as a relay trigger.

Also, don't you have any issues with running a return line that's necked down at the Racetronix sender? Any problems maintaining stable, low carb pressure?

 

[DoubleV]

And for claritys sake, I have the Racetronix fuel sending unit and their hotwire harness.

 

[CWPottenger]

What you see in 85GPLef41 picture is the relay of the hot wire kit mounted in the back of the car so the wires you see are from the kit. I can only speculate that he placed it there for ease of wiring and maintenance. As for a trigger wire to the hot wire relay in your carb application you can use any key on only circuit just extend the wire if not long enough to reach the place you want to attach it..

If your return line is at least as large or larger then the return size tube to the pump/sender assembly it should be ok. Before I switched over to EFI I had to change out one of my fittings on the return side of the bypass regulator because I was seeing issues with pressure variations because it was a restriction. I switched out to a larger line that reduced to fit the racetronix right at the pump. From that point on I did not have any issues.

 

[DoubleV]

I understand the wiring and how it's all supposed to connect. My confusion is coming from the fact I don't see how you personally have your grey relay trigger wire hooked up. Where did you connect it to? I know it needs a 12v keyed source but I want to know where YOU got that source from.

You also seem to be saying you're doing EFI now but you were running the Racetronix setup with a carb before. When you were running it with the carb setup, what size return line did you run that solved your issues? The restricted end on the Racetronix sending unit return didn't cause an issue? I thought I was going to have to replace the little Racetronix return nipple with a larger one.

P.S. I will be running a 3/8 return line.

 

[DoubleV]

OK well part of the confusion is I just realized I'm talking to two different posters.....

 

[CWPottenger]

Yep, two of us... 🙂

So I am clear:

My car is an 84 T-type Regal which was an original EFI Turbo car so I was wired for an in-tank pump, I already had the wiring harness setup for the pump. Racetronix setup is a direct plug in for the factory Regal EFI so plug -n- play. I upgraded my wiring to a painless wiring kit. That kit has a fused electric fuel pump circuit already. So I originally used that for powering my fuel pump when I was running the carburetor. Maybe 85GPLef41 will chime back in to let you know were he got his power from. Now that I have a F.A.S.T. EFI system on my engine I took the power from the fuse box and ran it to pin 86 on the fuel pump relay, Pin 87 to the 12v pump, and pin 85 to the fuel pump enable from the ECU (F.A.S.T. uses ground triggers not 12v triggers). This way the key must be on and the ECU has control of the pump.

As for the fuel side of it I have mine plumbed with 3/8 supply with -6AN connectors. My return from the bypass regulator was only 5/16 with -4AN connectors. I increased my return line to 3/8 and -6AN fittings and that solved all my issues. Was also nice when I did make the jump to EFI my fuel system was ready to go, just had to swap my bypass regulator out for a vacuum referenced adjustable regulator.

 

[DoubleV]

CW, when you increased your return line size, all of your issues went away even though the Racetronix return nipple size is smaller than the 3/8 line you ran to it?

 

[CWPottenger]

Yes, they did. I believe my biggest issue was the -4AN fitting at the bypass regulator was too much of a restriction exactly at the point of highest pressure and max flow. As soon as I went to a -6AN fitting and 3/8 fuel line my pressure was rock solid.

 

[85GPLef41]

my "grey" wire receives it's power via the factory ecm....once the antitheft was tuned out...the f body weatherpack just made it easier to splice