slimjim9059

93 Cherokee Sport, 4.0 HO... takes abnormally long to start.

I checked the plugs and wires, all are good and fireing clean
The last 3 tanks (since I have bought it, I have used seafoam in the tank)
I did a compression test and all 6 cylinders were reading 100-110. I think they were all around 110. They were all consistant either way,

However I did a fuel pressure test. Hooked a fuel pressure gauge up to the fuel rail and turned on the ignition so you can hear the pump come on. The pressure goes up to about 38-40 and instantly starts dropping off. The pumps never kicks back in to maintain the pressure. I'm not sure what is suppose to happen here but it doesn't seem right. I can also let all the pressure out with the fuel pressure gauge and the pressure never returns untill I key off/on. Then again back up to 38-40 and instantly drops off. It goes form 38-34-28-20-14... and slowly goes down from there.

Just for referance. If I go out in the morning, it takes forever to start. If I run into 7/11 for a few minutes it takes a few seconds to start. if I turn it off and start it right again. it starts right up. The longer its off, the longer it takes to start it. If I key on/Key off 5 times, then it starts right up.

So what the hell would it be?? I also noticed my vacum line (that runs from the vaccum canister on the left of the engine to two lines ontop of the gas tank) has a hole in it and the lines all ****ty, I cut it after the hole and slid it back in but the line is garbage. If that means anything, my buddy says it doesn't.

LittleMeanPurpleMachine

Fuel pressure check valve is letting the fuel drain back into the tank. Try priming it first by turning the key three time just till the fuel pump kicks in, then on the third time start it and should fire right up. Luckily you have a 93 and have external fuel pump so shouldn't be to bad to fix. Until then just do the old starting ritual as I call it.

Jareduhhh

X2 fuel pressure valve

crbnfibr

https://www.cherokeeforum.com/f2/199...arting-107124/

slimjim9059

Yeah I did the priming ritual and it will start right up like that. Is the check valve along the line somewhere after the pump im assuming?

Thanks for the advice, Ill have to check it out when I get home tonight.