I bought a 2000 recently that had a lot of modifications done to it. Cam, LS6 top end, 30# injectors. When going over it I noticed a wire from the fuse box mashed into a relay slot (to make it 12v switched) that ran across the bay, down to the rocker and, at that time I thought nowhere. I cut it out. Later the car wouldn't start. Turns out the wire was connected to a gray wire near the fuel pump. When I put 12v back to that wire, it started fine. Perhaps a work around of a bad circuit. But I ran into some other confusing things when trying to diagnose.

The schematic makes me believe there is a 4 pin connector with 2 grays, a blue and black that plugs directly into the pump.



But there are more connections in my case. This connector was plugged into an adapter joining to another connector and then a plug into the pump that has purple, red etc. wires. Nothing I see on the schematic. Here as you can see, the connector that matches the schematic color scheme is identified by the yellow arrow and where it was plugged in as indicated by the red.



Circled in green is where the ad hoc switched 12 volt wire was connected to one side of the cut gray wire. When I apply 12v to this the pump runs. But the gray wire leads away from the pump, not toward it.

Could there be some aftermarket pump controller in here? Maybe a mix of some aftermarket stuff and bad circuits?

 

Can’t help you with hacked up wiring and I don’t know if you understand how a relay works with a load and control side but one of the 4 terminals of the relay go down to the pump…your relay schematic below.

 

It looks like it might have a hotwire kit on it.

 

Moved to C5 Tech.

 

what's a hotwire kit?

 

It is a wire harness to provide higher voltage to the fuel pump to get more flow. Usually they go directly to the alternator.

 

A hotwire kit does not provide a higher voltage, rather, it provides dedicated path with appropriate wire gauge to prevent a voltage drop.

 

Racetronix claims a round a 1-1.2V increase, but your statement is probably more true as it creates a more consistent voltage to the pump.

 

Well whoever installed this probably wasn't too concerned about voltage drop because the power side was simply stripped and conductor stuffed into a relay slot in the fuse block and a relay stuffed inside to hold it.

 

Yep, i do. I applied 12v to the A12 socket and went to check for voltage at the pump plug when I discovered these extra connectors. The harness that new wire was spliced into runs toward the drivers rocker. Not sure it there is supposed to be a harness coming from there.

But I'm correct in thinking the plug that connects to the fuel pump module is the one in the schematic, blue, black 2x gray right? Nothing else after at least from the factory.

 

ooh, i think you're on to something. I went to their page and looked at their kit and this all looks familiar.