the209bnr

Long Story shot, i've had an issue with my car running poorly at times then running great again. I replaced everything i could imagine such as plugs, wires, cap, rotor, coil, fuel filters ect. in hopes of solving the issue.

Issue went away the other day when it ran out of gas. Filled it up and ran great again until this sunday during the NorCal Cruise to Cruz event.

I noticed that when my car runs great there is a "whoosh" sound that comes from the gas tank when I unscrew my cap, and when its running poorly there is no sound at all, like there's no pressure in the tank?

I think its the fuel pump but not 100pecent sure. If so any recommendations on what I should do and what kind of pump to get? I can't afford to keep investing a few hundred into the car every month and would like a long term solution/fix for this problem even if it is more expensive!

the209bnr

and in re' the sound in the tank, it sounds like a popping sound and the car hesitates when this happens, i have to let off the gas a little to get it to stop

the209bnr

Bump

TwinTurboROC

The whoosh is just residual pressure in the tank being relieved. Normaly your vapor canister would collect this, but possibly did not have time to flow into the canister.

I didn't understand what the "re' " was in reference to or the second post honesly.

Are you sure the popping is from the tank or the engine. If your timing is off, you can get hessitations at higher engine temperatures.

You can check your fuel pressure when it starts acting up. That should let you know if fuel has any relation to the problem.

the209bnr

It's coming from the rear, and noticed it on a long drive saturday, it almost felt like the car wasn't getting enough fuel because it would sputter/hesitate

TwinTurboROC

Check the fuel pressure. You may need to do it under load, aka driving. As sometimes reving alone wont show a drop in pressure or volume.

TwinTurboROC

By chance do you have a L69 engine, not a L96?

the209bnr

OOPS.. yes its an L69. and call me stupid, but how would i go about checking the fuel pressure?

TwinTurboROC

Ok so you have the mechanical "electronic" carb. (should be the 305 HO motor) One way you can check is by t-ing off the main feed line with a fuel pressure gauge.

Those carbs were a bit problematic. At one point there was a TSB about adding a intank electric fuel pump to cure some problems. And there was bowl refit kit for them that raised the inlets higher (or someting to that effect).

Alot of them could just use a good old rebuild though. How old is the car , Carb ever been rebuilt?

the209bnr

Its all original mechanically wise, has 61k original miles on it. It was a "grandpa" car as it was babied and looks like it probably did leaving the factory (except for the 85 rear bumper and lights swap)..

I swapped plugs, wires, cap, rotor, coil, oxygen sensor, flushed all the fluids out and put fresh ones in it thinking it could be that but it wasn't. the only thing i do notice is that the carb floats don't close all the way unless i manually do it (the larger one anyways)