Engine/Transmission (1994 - 1998) Low Fuel Pressure

[TEasley]

While I'm getting ready to do the KDP, I finished a mechanical in-cab fuel pressure gage. Finished after dark, so haven't done any troubleshooting. Idle pressure at 750 rpm is 13 psig; Cruising unloaded at 65 mph and 1750 rpm, pressure is 17 psig. Pressure tap is a small needle valve that I installed in the fuel inlet banjo bolt at the back of the injector pump. (saw it in the forum) From what I've read in the 12V forum, this is way too low. I found the return line from the front of the pump, but didn't find where it transitions to hose. Maybe easier in the daylight. After that, I'll service the pre-filter. I hope the problem isn't the lift pump.



Any troubleshooting tips are appreciated. Meanwhile, fuel plate is on hold until the KDP is done, and I get the fuel pressure up.



Thanks, Tom



Truck is a turd brown '97 Xcab long bed auto trans, 2 wheel drive with 3. 54 Dana 70 L/S, with pyro, trans temp, boost and fuel pressure, dead cat, 3" straight pipe and flowmaster, ex GMC Airaid. 132,800 mi. Best truck I ever had.

 

[Cooker]

The most common reason for low fuel pressure is a weak overflow valve.

 

[TEasley]

Signal73: Went back and re-read your post on building a fuel pressure gage.

The banjo bolt tap worked good. Also the info on pressure confirmed that my fuel pressure is way too low. Good stuff.



Thanks, Tom