I have been having problems with my car dying. Today I figured it out. I thought my fuel pump was good, but it must be bad. Fuel pressure starts out at 42 psi when cold and drops to 22psi when warmed up (195). After it gets warm (210 degrees) it drops to 16psi and then to 14psi and dies. I pinched return line and fuel pressure does not rise. This pump is 4 years old and has 800 miles on it maybe. It was an edelbrock pump out of Jegs or Summit. I thought it would be better than the napa or carquest ones that have not lasted before. This is my 8th fuel pump in 20 years. I wanted to know if there is an inline pump I could use instead of the in-tank one. Also, I wanted to know if there is anything I should check that might be making these pumps not last? Would the fact that I am only getting 22psi of fuel pressure when cruising down the road make my engine heat up and not want to cool down with the fan running? I have a aluminum high flow water pump and high flow thermostat and aluminum radiator with electric fan that kicks on at 180 degrees.

 

Surprised the engine even runs with fuel pressure that low but lean engines do run hotter than normal

 

Didn't even know that edelbrock made an intank replacement pump for 3rd gens, personally I'd just replace it with a good quality intake unit like a walboro or a delco, replaced my stock delco pump last year, but it lasted a little over 22 years, not exactly what Id call high maintence. Are you sure your gauge is accurate? Didn't think injectors would even operate at 22 psi. Even if the gauge isnt on the money it's clear that there is a problem with the pump, either the pump is on its way out, the rubber hose between it and the sending unit is leaking or a clamp is loose... I will admit the design makes it a pain to r and r in a driveway, but on a lift it's a 20-30 min job (assuming no rusted in bolts snap etc) also helps to have an exhaust that can be unbolted and removed but since my 89 is still rocking the entire factory system I simply cut the pipe with a sawsall before the muffler, removed it, unbolted the panhard bar from the diff housing, and may have unbolted the shocks from the bottom mounts and unbolted the swaybar bushings from the diff housing, while supporting the rear with 2 screw jacks, then lowered it out of the way, unclamped fill hose from tube, unplugged eletrical connectors and fuel lines and unbolted tank straps while supporting tank on a trans jack, removed sending unit, replaced pump, strainer, the short hose from pump to sending unit as well as clamps, removed old sending unit gasket from top of tank and replaced with new 1, put sending unit back in and reassembled everything and welded muffler back on, and put a new fuel filter on for good measure within 20 min to a half hour start to finish. That being said if you never want to drop the tank again you could removed your sending unit, replaced it with a sending unit for a carbed model and install an inline pump such as a holley blue unit where your fuel filter is, fab a small section of hardline after it, cut the line in front of it, install a fitting, flare the end and put your fuel filter there and never need to drop your tank to replace a fuel pump ever again. Also as stated running lean will cause your engine to run hot.

 

My car had about the same issue your car is having. The car would cut out, not make good power in the uppper RPM's and it got to the point where it would only idle if the car was warmed up. The shop tested the fuel PSI and it was good. My PCM was bad as well so they thougth that was the only issue. Put the new PCM in and it ran good till it warmed up then the bucking and stalling happend. They tested the fuel PSI again and the pump was bad. I had them install an AcDelco pump.

It would be nice to have an inline pump so you never have to drop the tank again.

 

Especially since I have custom duals and have to cut them off every time.

 

[quote=89RsPower!;5295381]Didn't even know that edelbrock made an intank replacement pump for 3rd gens. Are you sure your gauge is accurate? Didn't think injectors would even operate at 22 psi.




The injectors were operating at 16 psi barely until they dropped to 14psi and it died. Here is the edelbrock replacement pump from JEGS.

Edelbrock 17933 - Edelbrock High Performance In-Tank Fuel Pumps.
These OE in-tank upgrade pumps are ideal for supporting performance improvements such as a high performance intake manifold, cams, turbo, direct port nitrous systems, big-bore throttle body, etc. They replace your original pump exactly and include all necessary hardware for an easy installation.

 

I keep checking everything hoping I don't have to change the fuel pump. I put heat shields over any part of the fuel line that is close to the dual exhaust and that didn't seem to help. I pinch the return line and my fuel pressure stays at 24 pounds and doesn't rise. I would have to think that it is the fuel pump then.

 

Replaced the fuel pump and that fixed everything. Really runs good now. Now for a road trip.