GTM4ME

I have a LS376/480 with harness and computer from GM. I am using 2000 Vette tanks and I am not getting any power to the fuel pump. If I bypass the fuse box/relay and wire the pump directly, the car will start. Can anyone point me in the right direction where to start looking. Engine is in a Factory Five GTM so there is currently no other wiring installed at this time.

Thanks,
Mike

Monte_LS3

Mike:

Just finished a Monte w/ the same harness controller. A couple points:
a) I know the GM instruction manual says you can hook 8ga incoming power to any of the three lugs on the fuse/relay box, this is incorrect... There are 2 8mm vertical lugs labeled A and B and a 6mm horizontal lug. You want incomining power connected to the horiz lug (you must provide your own fusing). Lugs A and B are series connected through the two 50a mega fuses in the box, and can be used for auxiliary power feeds. I've refused the A circuit to 25a and power my ac circuits.
b) I think your problem (not really a problem) is that the controller is looking for 12v "Ign Switch" power prior to energizing the fuel pump circuit. This "Ign" is labeled in the harness and tees off close to the drive by wire throttle connector.

In summary, think your electric fuel pump circuit will work if you supply 12v power to the 6mm horiz lug on fuse/relay box and 12v to "Ign Switch" wire

GTM4ME

Thanks for the reply, I do have power in to the 6mm lug and also have power to "Ign Switch" pink wire near the drive by wire connector.

Monte_LS3

a) Fuse OK to Electric Fuel Pump?
b) Fuel pump Relay OK? Switch another relay into the fuel pump position
c) Is a sequencing problem? Remove all 12v power, Connect power to 6mm lug, Then Connect power to "ign switch" lead

GTM4ME

Fuse is ok, power to both sides. Relay is ok, swapped with another that I know works. I'll try the sequencing thing. Thanks for your help.

Mike