Simple Term X fuel pump question
All the stuff I have seen from them, all use the factory fuel pump power wire to turn on the hotwire relay, but I have not used one of their dual setups.
I am more than slightly confused.
IF it is ground side switched, it should be wired like this;
(low current/control side)
85-switched 12v source
86-ground switched output from the Holley ECU
(high current side)
30-battery or alternator
87-secondary fuel pump power wire
The primary PCM fuel pump power is used to supply + to both the relay coils via the gray wire. This is normally supplied by the factory fuel pump circuit via the IDPH harness.

Manufacturer / Distributor of Automotive Fuel Systems, Components & Electronics
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Depending on the model of pump the draw may be too much for the PCM driver.
The relay and fuse in our harness is more robust and much easier/cheaper to repair/replace than a PCM driver.

Manufacturer / Distributor of Automotive Fuel Systems, Components & Electronics
Please support a Racetronix dealer near you for personalized service.
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The primary PCM fuel pump power is used to supply + to both the relay coils via the gray wire. This is normally supplied by the factory fuel pump circuit via the IDPH harness.
*EDIT* So, I believe I have figured out the problem. When doing the output testing, I was only testing the individual output, which was working fine. What I failed to realize is unless the Holley main fuel pump output is ALSO triggered, pin 86 on the Racetronix relay is receiving zero voltage from the factory fuel relay, which means the pump won't turn on. I plan to test this when I get home from work.
Last edited by LS1Formulation; Aug 25, 2024 at 05:05 PM. Reason: Figured out the issue












