Does anyone know which of the relays in the engine bay is for the in-tank fuel pump in the LG4s? IIRC, I have 4 relays in the engine bay now, but it might save me a lot of trouble if anyone knows which one was it. I don't have complete car wiring schematics, so probly the only way to find out is to check for continuity between the tank plug in the back and each individual relay wire (I do however know that the power wire for the pump is grey, since I just swapped pumps this weekend). Thanks for any info, it is greatly appreciated!

 

Interesting, I would have never guessed an LG4 to have an elec fuel pump since it's carb'd. Learned something new today

 

Yeah I have a LG4 too and I didnt even think it had an electric fuel pump lol.

 

It does, its shorter than the TPI pumps, and puts out like 3-5 psi. In order to switch to a TPI style pump, all you have to do is cut the hard line by about 1" to fit the new pump in.

 

Actually, I'm not sure that all LG4s do, but I've heard the L69s and the late-model LG4s came with them. Obviously, my '87 did.

 

My 86 LG4 only had the mech pump on the block and no pump in the tank, same on my friends 82 T/A LG4.

 

In 86 or so, due to peoples complaints of vapor lock, GM decided to install an in-tank "helper" pump. So, for 86-up carb'd cars it was factory. For the pre-86 cars, the customer could take it in and have it installed.