Why is my fuel pressure high?
Asked by glance1973 Jan 02, 2015 at 03:42 PM about the 1994 Chevrolet S-10 LS Extended Cab RWD
Question type: Maintenance & Repair
Pressure with engine off is 41 PSI but while running it jumps to 60 PSI. Volume test while running was also poor.
2 Answers
If it is a 4.3 it needs 55-65 psi to run. 41 while off indicates a weak regulator or fuel pump check valve
glance1973 answered 9 years ago
It's a 2.2. New engine, injectors, pump, filter, sensors.....basically this truck sat for 7 years and I've replaced almost everything under the hood. Blew out the fuel lines. Return line was clogged and blowing the FPR and causing fuel to flood the intake. Replaced the fuel cap today and it ran somewhat better. On the fuel test I ran, the pressure didn't drop until 20-30 mins later and dropped to 30PSI. I bought an evap canister filter and will change that out this Thursday when I'm off work. The only thing left I can think of is the actual fuel lines, or the pump I bought is faulty.