94Z28LS1toLT1

Hey guys when i drive my car for awhile around my fuel take builds alot of pressure i can here squealing from the tank.and after i turn the car off then turn it back on its squealn too,i also take the gas cap off alot of pressure.too

mrmint69

Lots have excessive pressure. You are in a hot area for sure, that affects it much more. I think there is a pressure release valve that is suppose to help with that problem. I notice lots of posts on here, so a seach will result in tons of reading.

94Z28LS1toLT1

Lol yea man i noticed the posts too i did change the fuel filter it was bad very clogged up but would that make a difference.n also where is is valve u mentioned located at thank u

mrmint69

Fuel filter only helps improve pressure on the fuel rails. Think its by the fuel pump, left rear wheel area.

94Z28LS1toLT1

Fuel pump is new but last year these idiots said i needed it changed n ever since they messed with it there was a leak from the fuel tank vent valve,it leaked bc the evap purge solenoid was undone,but i haven't heard the tank being noisy but can the pump be the issue

mrmint69

If the squealing is from the fuel pump, then maybe it has a problem. It should sound like a buzzing sound, if working correctly. Where exactly is the squealing noise coming from?

94Z28LS1toLT1

Yea when i turn the key i do hear the normal buzzing sound but the noise was coming from in the tank but i noticed after i drive my car for awhile the car has been firing up
very fast N primes nice the pump.i think it had to be the fuel filter bc the gas that came from the old filter was dirty n u couldn't blow air thru it clogged bad

Injuneer

Fuel tank pressure is generated by the vapor in the fuel tank. Isn't going to be affected by a clogged fuel filter. The vapor load in the tank is affected by fuel temperature. Heat the fuel up and you generate more fuel vapor that has to be vented. The pressure is vented by the EVAP system, through a pressure regulator in the line from the tank to the canister, through the charcoal canister in the driver's side rear fender. The canister could be plugged up, or the pressure regulator valve may not be working.

High fuel temp can be caused by the lines being routed too close to exhaust components, or an oversize fuel pump that recirculates a larger amount of fuel than a stock pump. A failing fuel pump can also cause the fuel to heat up.

If the pressure becomes excessive, there is a pressure vent/relief valve attached to the chassis, right in front of the tank. If that vents, you are going to smell fuel at the rear of the car.

EVAP system components:

http://shbox.com/1/evap_system.jpg

PRESSURE VENT VALVE:

http://shbox.com/1/fuel_pump_wiring.jpg

94Z28LS1toLT1

Hey Fred the pressure regulator valve u mentioned is that the fuel regulator valve?also my fuel tank vent valve is new.but its gotta be the lines being ttoo close to the exhaust or the charcoal canister is clogged but would that set any engine light?

Injuneer

No SES lights in a 94 for anything in the EVAP system except the purge solenoid eletrical circuit. No codes for fuel tank pressure or components.

The EVAP (tank) pressure control valve is not the fuel pressure regulator. Look at the first link above. The pressure control valve is clearly shown.

94Z28LS1toLT1

Fred....oh yes i understand now that pic,but i remembered my tank making that noise when my gauge was kinda of below the 1/4 mark could that cause the tank to pressurize?

Injuneer

The less fuel in the tank, the faster it's going to heat up.

94Z28LS1toLT1

Hey Fred so i bet thats wat is was i remember rob saying on a post to not let the go below
the 1/4 mark,so reading ur reply the fuel heating up will build pressure

94Z28LS1toLT1

Hey Fred after driving awhile,as i make sharp turns i can hear the pressure in the tank,also when i got home i took the gas cap off the air pressure wouldn't stop coming
out when i put the cap in pressure keeps coming out. Now am i suppose to take the cap off when im done driving,,or am i suppose to leave it be. Should thete there be that much pressure in the tank dudes.thank u.ps the car didn't start on its first attempt after all that pressure in the tank it started on the 2nd attempt

94Z28LS1toLT1

Hey Fred the diagram of the charcoal canister i see the three nipples i readf one of each one i see the one about purge does that connect to the purge solenoid?the middle part is for the air to come out so that doesn't connect to anything,and the one that says tank i can figure that one.but thete is way too much pressure in tank its scary the shop had to route them wrong,i,i never realized it bc i never drove longb4