I have a 94 Z28 A4 and installed new pacesetter longtubes. My question is car is running really rich and I put a fuel gauge on it and it stays at around 32 and drops to about 30 at WOT. When it gets warm and at idle it runs rough but when I drive it down the road it runs good at WOT. Just curious if my fuel pump is going out. Just got my computer back from pcmforless and was also wondering if he would adjust it for fuel pressure. My car has 130K miles and still has the stock fuel pump. Also I have seen some inline fuel pumps and was wondering if this would work with stock fuel pump.

thanks
Josh

 

41-47 psi is the normal range with vacuum line to the regulator removed. It should be the same at WOT, but somewhat lower at idle (maybe 6-8 psi). An inline pump will not really rescue a failing in-tank pump.

Change the fuel filter, if it has been a while.

 

My car is doing the exact same thing. Around 35 psi at idle, then it goes up to 40 psi or so under light acceleration and drops to 30 psi under WOT. I'm installing the Ractronix pump next weekend which should fix it for good. I still can't believe I managed to spray a 125 dry shot through the motor and it's not damaged. I didn't even know the pump was going out until last wekend whe I sprayed it at the track and it ran 94 MPH in the 1/8 and only 109 in the 1/4. The thing usually traps 107 N/A, and may trap more once it has a proper fuel supply. It seems that everyone is recommending the Raceetronix kit, and I picked mine up for ~$160 from Thunder Racing.

 

thanks for the help, I just took it down the road and it actually ran fine. It held 35 idle and 40 at WOT. But still ever since the header installation car runs rich and service engine light comes on when it get warm. Plus the rest of my exhaust fells like it is going to come through the floor board. One last question if I have it scanned and the sevice engine light is not on, will it still throw codes. If so where can I have it scanned at.

thanks
Josh

 

If the light was on, the code is stored for the next 50 drive cycles, even if the SES light is off. It can be retrieved.

The most common causes for "running rich" are exhaust leaks before the O2 sensors and misfires. Both of those can be the results of a header install..... leaking exhaust gaskets an slip-fit primaries, or burned wires.

 

thanks, I checked for exhaust leaks and sounds ok and I have the checked for burnt wires several times. Just curious, if I still have the orginal O2's that came in the car could this give me a problem. Car has 130K miles on it and the O2's have never been changed.

Thanks
Josh

 

I would say they are way past due for changing.