now151

i have a 2002 grand cherokee lerado sport 4.0 with 99,000 mi. it was getting hard to start. put gauge on fuel rail. i loose fuel
pressure rapidly and causes hard to start. i replaced fuel pump unit in tank and fuel filter regulator. i still loose fuel pressure. does anyone know if it would hurt to put an inline checkvalve in the fuel line. i'm thinking that the new fuel pump assembly is still causing the pressure drop, but i don't want to replace it again if a check valve will work. any comments? thanks

tiwvr1

Could be a injector sticking a little, bleeding pressure off.

caged

check valve. common problem.
just put one inline as close to the tank as you can.

now151

i finally, got the fuel pressure leaking down taken care of. it was the injectors. after changing the fuel pump , regulator filter combo and installing a check valve on the fuel line (which was not a good idea)and still had the fuel pressure leaking down . wish i had started troubleshooting from the injector end to begin with. oh well. with the added check valve in the fuel line when the engine warmed up and the heat from the engine compartment would heat the fuel rail hot enough to cause the fuel pressure to reach well over 100psi before gradually coming down .i guess where i put the check valve trapped the gas causing the regulator to not be able to do its job. it was nice finally getting rid of the hard to start problem.

blinkbears

I always love a happy ending

Gee oh Dee

Moved to GC Tech.