i have a 1986 camaro with the lg4, it has a mechanical pump on the engine, i'm going to do a tpi swap but the bulk head behind the back seat has 3 wired, a thick pink one, a brown one and black ground, why would i have these if there is no electric fuel pump? although some say a low pressure helper pump could have been installed, why dont i have a fuel pump fuse in the fuse block? help!

 

There is still a sending unit in the tank. It has a float on it with a varible resistor that is wired to your gas gauge in the dash. Thats how it knows how much fuel is in the tank.

 

yes i know that, but that only requires 1 wire to the fuel level gauge, obviously there is a ground

 

The fuel pump fuse is under the hood bolted to the fender right behind the radiator support.

 

There are three wires there because of the electric fuel pump that is in the tank. Now before someone starts blasting me and saying things like "but its got a mechanical pump at the engine". Let me say this, yes the LG4 and the L69 engines both had mechanical fuel pumps, however the L69 engine also had a electric fuel pump in the tank which was used as a supply pump to provide fuel to the mechanical pump at a rate of 3 PSI. Also in their infinite wisdom, GM incorporated the wiring for the electric fuel pump in all the models off the assembly line. This saved them money by not having to make up a bunch of different wire harness's for each model. If it wasn't used then it was just tucked up out of the way.

 

sweet, thanks trickster!

 

And that wire would be the tan (brown) one.