fuel pressure

[Rangerman87]

the fuel pressure in my '88 2 nine sc seems a bit too high,by that i mean when i loosen the filler cap it has way too much built up pressure,what would cause it?

 

[DisturbedMXer8]

Faulty FPR, fuel pump that's stuck on... what kind of pressure are you reading, though? No way to know it's too high unless you get an accurate reading.

 

[jhammel85]

I know that an evap tube from the tank can be clogged and not allow too much pressure to escape. Not to sure about our trucks though.

If it has high fuel pressure, your FPR could be bad. Mine spiked past 100 psi and would spit black smoke like a diesel. After I replaced it, I was back to normal PSI.

Basically, I would check fuel pressure. If its high, replace the FPR. If it's just hissing when you release the Fuel Cap, I wouldn't worry about it.

 

[RustedRanger]

How bout the gas cap....is it old? The solenoid for the evap could be bad or the evap cannister might clogged. Is it running rich or are you talking about the pressure build up in the tank only?

 

[Rangerman87]

When I unlock the cap there's a loud hissing,never had that problem before.

 

[RustedRanger]

You might try a different gas cap,it could be as simple as that.