Fuel Pressure?

Tbuck07 · Mar 8, 2010

So I got my car (89 lx 5.0), and the guy that had it before me had the fuel pressure leaned out wayyy too far. I didn't have a fuel pressure gauge, so we basically upped the pressure until the backfiring went away. I had the pressure tested at a dealership and it was at 76PSI. I know thats high..It wasnt doing really bad on gas..and wasnt backfiring. Well they tuned it back down to 42 (off vacuum) and now its backfiring and feels like its leaning out..I turned my regulator a few small turns but its still backfiring/not running correctly. I have a gauge now, and just need to get the tool to remove the shrader valve..but I wonder if maybe it does need to be up at 60-70 psi to run correctly? Its got gt40p heads..trickflow stage 1 cam, street burner upper/lower..gears, etc..I dont know. *shrug shrug*
12* of timing as well.

2slo95fiveoh · Mar 8, 2010

When you hook the gauge up for fuel pressure, you don't need to remove the shrader valve.. And something else is wrong with the car
if the fuel pressure is set at normal and it doesn't run right.. When was the last time the car had a good tune-up (plugs, wires, cap/rotor, coil, fuel filter)? And also, with an aftermarket cam, it will more than likely need a tune, which can cause drivability issues as well.

Tbuck07 · Mar 8, 2010

Just replaced plugs wires..all is done right..and its been tuned recently.

Tbuck07 · Mar 8, 2010

And I do too need a shrader removal tool..I dont have anything else I can fit in there

94Snake · Mar 9, 2010

put a wrench or socket it on it that's what i did. are your injectors clogged? if so lemme know, i have some 19lbers that came off a buddy's car. he went to a carb setup for some reason.

94 DropTop · Mar 9, 2010

Yes, something on your car is f'ed up, and its not the fuel pressure. Have you tried to check your car for codes?

gregbar · Mar 9, 2010

If you need to remove the guts of the shrader valve they make a little tool to get it out. Bike shops have them. 60 -70 psi is way too high something else is wrong. Check firing order and that the wires are on correctly.