Keep having issues with the fuel delivery on my track car. It's a 1982 Toyota Corolla with a 12a swap. Stock nikki carb, but the previous owner of the motor blocked the return line off. I'm using an electric low pressure pump to feed the carb.

When driving for a while I'll notice the float levels getting low and eventually drain completely stalling the car. For periods of time it runs perfectly fine and for others the car will just completely drain.

I also have a plugged vent tube coming from my gas tank and was wondering if that could be part of the issue. Is there a problem with running no return line?

Thank you.

 

It sounds like you are just dealing with delivery issues. So, first thing to check is the fuel filter (possible restriction). Then, make sure that the fuel pressure regulator is not set too low. Then, make sure that the pump itself is up to the task.

Good luck...




.

 

if the vent is plugged that will do it. if you remove fuel from the tank, it needs to be replaced with air. if not then the fuel pump has to pull against a vacuum, and that wont work!

so try driving with the gas cap off, if that fixes it, you need to look at the vent. efi cars do this a lot, the charcoal canister plugs, and since its on the vent...

if not it could be some sort of junk in the tank/bad fuel pump issue. i've seen fuel pumps that work better when cold.

a 12A shouldn't have this problem, but i did have a gsl-se that has a fuel filter that was so cheap, that it rusted out and clogged itself.

 

I'll try replacing the vent tube to the tank.

I've been thinking of running a surge tank, and will resort to that if all else fails.

Any tips on checking if my fuel filter is plugged? It came with the pump, it's a small brass canister that looks similar to a C02 canister.

 

best way to check the fuel filter is by removing it and blowing through it.

 

Don't bother replacing the vent line to the tank unless that is the issue. The test to determine if this is your issue is very simple, just leave the gas cap loose. If that solves the problem, then you'll know that the vent line is the cause.

If that filter is as tiny as it sounds, then junk it and get a stock filter on there. I'm leaning toward this being the issue. The small size is probably causing a restriction that allows your carb to outrun the pump...

 

It's a electric pump designed for V8's, though replacing the filter won't hurt. The Vent tube is 100% blocked as the tank sucks a ton of air in when removing the cap.

 

its not actually a stock nikki quinn. It has manual secondary conversion. Look up the lean flat spot problem than comes with the manual secondary conversion.

 

gas tank must have some vent.