Did the LG4 originally come with a mechanical fuel pump or a low volume in-tank one?

 

mine has a mechanical pump......i'm guessing that this is added by the previous owner though

 

My 85 IROC LG4 has a mechanical. I replaced it a few weeks ago with a stock replacement.

JamesC

 

I don't know that I've got the straight story, but what I've HEARD is that a dealer-installed anti-vapor lock kit was available that put in the in-tank pump and added a fan to blow air onto the carb when the engine was shut off. My donor car had the blower, but as far as I know, did not have the in-tank pump. The other part of the story is that all '87's got the in-tank pump along with the mechanical pump on the block.

The Chevy High Performance magazine article series "My Generation Camaro", an '87 LG4, apparently had the in-tank pump, but no mention was made of the blower. They did talk about a weak mechanical pump that they replaced to get it running right.

 

i haven't checked at the gas tank yet but there's a connector for an oil pressure switch in the harness so i'm assuming there's an in tank pump? if there is should i also put on a mechanical one? either way do i need a pressure regulator for the electric pump?

 

You should use a mechanical pump that includes the return line. The pressure is regulated by a relief valve inside the mechanical pump, to the return port, so no regulator is needed.

CHP didn't do that, just used a standard two-port performance pump; not sure how they got by with it (could be the electric wasn't working, and they were just sucking through it - might explain some of their problems).

 

should i use the mech. pump along with electric then? or just mech?

 

If the electric works, I'd use both.