'98 Rodeo low fuel pressure

[Max Tork]

My rodeo has been hard to start when cold for quite some time. I've replaced the fuel filter with no effect. The fuel pressure on the fuel rail is 25 psi. My Haynes manual states it should be 42 - 55 psi. Also, the fuel pressure drops to zero when the engine is shut off. I don't know if there is a check valve meant to retain pressure in the rail for the next start. If there is, my isn't working.

Also, when driving the CEL sometimes will light when stepping hard on the gas. I don't remember the exact code, but it seems like it could have been caused by not enough fuel.

My gut says that it is a faulty fuel pump or fuel pressure regulator. What do you all think?

[Gizmo42]

Fuel pressure regulator is bad is my guess.

[trooperbc]

Originally Posted by Max Tork

...
My gut says that it is a faulty fuel pump or fuel pressure regulator. What do you all think?

. . .your "gut" and that pressure test

i'm trying to remember, is the fuel pressure test valve prior to, or after, the fuel pressure regulator.

if after, so the fuel pressure regulator is tested as well, then i'd go first for the regulator. if before, then you're only testing the fuel pump.

the drop to zero seems to point to the reg too
time to differentiate. post that code.

good luck

/bc

[2eyefishclaw]

if you are able to check fuel pressure with a guage just piinch off the return line then have someone turn ignition on this will tell you if the fuel pump is capable of supplying sufficient pressure should be somewhere around 60-65 psi if not put a pump in it if it will build enough pressure shut key off let go of hohse that is pinched off if fuel pressure drops right away you may have a bad regulator or valve in the pump net is to get a clear hose to connect to the vacuum supply line to the fp regulator start vehicle if there is any fuel in the clear hose replace the regulator if there is no fuel replace the pump