Okay everyone, I got the new motor in my car, see sig. I had an LG4 before. Now here is what I don't understand, I switched to a 350 mechanical fuel pump on the motor. However with the motor off and the key turned to the accesories the carb bowls were filled and i hear this whirring sound at the back of my car. Am I still pumping fuel? Or is this sounds okay? and if I am pumping fuel, is this sound okay?
Thanks

 

This is not good, the intank pump is pumping 40+psi...it will blowout the mechanical and most likely your carb given time. You only need 5-7 at the carb. You can try pulling the fuse 0n the electric...the mechanical may pull through it . some will some wont..if it wont you could run the electric with a 3port AFPR. Or you could drop the tank and switch out the pump and just drop in a line.....I chose the 3 port and havent had any problems...just block the mechanical

 

Really? I wasn't aware I had a fuel pump down there, I though all LG4's had a mechanical pump at the block!

 

Hope I'm not off base here......I could be. Check out this thread.......https://www.thirdgen.org/techbb2/sho...hreadid=110440

As I said I may be wrong. But I sure dont know what else could be making noise, except maybe your hatch motor....



This fuel pump issue comes up alot...I'm going to do a little more research on the topic...if it is a stock carbed motor, and it has a stock intank pump...I wouldnt think you would need to step down the pressure, as with the injected systems.
I hate it when I make bogus suggestions.....there seems to be alot of variables when it comes to fuel pumps and 3rd gens.

 

Exactly, thats why I am so d*mn confused. I just don't know what to make of it.....hmmmmm. If it is the intake pump shooting 40 psi at my motor I will just go with the afpr, but with that do I need a fuel pump at my motor or do I just extent the lines (not a big deal) up to the carb?
Bob

 

You wouldn't need the mechanical. Just block it off with a plate...as for the regulator, if the intank pump is for the carbed motor..low pressure, I dont think you would need the regulator. To be sure, you could disconnect the fuel line at the mechanical and see if the electric is pumping fuel..then a pressure test/gauge would tell you if you need a regulator or not. Sorry about the IFFYness of this post, but there is alot of confusion with your year of car. I think we may both learn something here if we wait a little while......where are those gurus when you need them!!

 

Ah, I see you're posting the same question on two different forums (answered on Carb as well).

All LG4's did have a mechanical pump. To repeat, you need a pump with 3 ports, which will allow excess pressure & flow to return to the tank.

From what I've gathered, all '87 LG4's had the in-tank electric pump. Earlier models may have had a retro-fit kit installed by the dealer if the owner complained about vapor lock. It included a little blower motor behind the battery in the passenger side fender to blow air on the carb when the engine was hot and turned off. My '86 donor car had the blower, but not the in-tank electric pump (not sure exactly what was up with that).

 

make that 3 boards...I really wanted to know.. ...https://www.thirdgen.org/techbb2/sho...894#post706894

 

At least the answer was the same...

 

My favorite Guru...:hail:
I love this stuff...maybe I should hang up my hammer and get me some wrenches............................Naw..