Brute03

guys, i'm getting two different fuel pressure readings at the same time. the gauge on the rail reads a measly 26-28 psi while a scanner hookedto the odb port reads 40 psi, wtf?

my car is running like crap right now, could this be why? i've tried just about everything else

BolognaPony

a mechanical guage, if its not faulty, is probably showing that your FRPS is bad.

Brute03

that was my guess too, but that's an 80 dollar part and i want tobe sure. is there any way the test it with a multimeter?

cliffyk

[/align][/align]Here are the "expected FRPS output voltages" for certain pressures, from the shop manual:[/align][/align][/align][/align]Test between the FRP Signal and SIG RTN pins. If the reading is around 2.8V then the PCM is correctly interpreting the sensor's output.[/align][/align]The shop manual does not list any resistance orother testsfor the sensor itself, however it does state that if the reading from a mechanicalgauge (of known accuracy of course) is not within 10 psi of the PID then the sensor or something 'tween there and the PCM may be defective. Checking the voltage as shown above should rule that out however.[/align][/align]You could check your mechanical fuel pressure gauge against an air pressure gauge if you have a compressor--it won't be a blanket validation, however if the mechanical f/p gauge and your air gauge read pretty much the same then it's likely it is accurate enough for this purpose...[/align][/align]

Brute03

thanks alot Cliff, i'll try that when i get home

oxfordgt

Have you tried disconnecting the vacum line from the fps. With it connected you should read on your gauge 29psi with it disconnected you should read 40psi. Sounds to me like your running correct.

What is your car doing that it runs like crap?