I've got a problem with my fuel pump fuse blowing intermittently. It has to be a short. I've traced the problem down to being between the power side of the fuel pump relay and the bulkhead at the back of the car above the axle. Im suspicious that the side of the power wire taht goes down to the oil pressure sending unit is getting intermittently shorted out on something, blowing the fuse. I read a few other accounts online of this happening.

I havea 92, so I have the 3 wire oil pressure sending unit. if I remove the gray/tan wire going from the relay to the OPSU, does that mean the OPSU isnt getting power to send a signal to the gauge?

Basically, does anyone know what the 3 wires in the OPSU plug do?



This didnt help much, but neither does this...




But if Im intepreting it right, if I cut that tan wire going to it, the OPSU should still send a signal to the gauge cluster, right?

For the record, every other part of the fuel pump circuit taht I've looked at looks fine. The fuses only stopped blowing every few minutes after I started digging around in the harness around the OPSU. I havent found any blatant issues in it, but it seems to have "cured" itself for now, but I dont trust it to not strand me somewhere again.

 

Tan is signal wire for gauge (C100, E5).

https://www.thirdgen.org/forums/ltx-...formation.html

post #1, "stock fuel control" and "simplified fuel control", it is a reference for lsx/ltx swaps but will give you an idea of what you are working with.

 

The tan wire that I cut ended up being a power wire from the OPSU, not a signal wire. Weird that tehy use two tan wires like that, but this one is clearly soldered directly into the main power output of the fuel pump relay.

The C100 connector seems like a nightmare. I havent had any further issues from it, but if more crop up I'm going to have to dive into it.