Troubleshooting fuel system, no start

  • i disagree if the check engine light comes on the ecu is firing up.


    If u have spark then u dont have fuel. Either no pressure from the rail or injectors are not firing. Im still betting on a bad fuel pump or wiring to it

  • i disagree if the check engine light comes on the ecu is firing up.


    If u have spark then u dont have fuel. Either no pressure from the rail or injectors are not firing. Im still betting on a bad fuel pump or wiring to it

    thats what happened to mine wireing to pump where it connects pump wirein did not match factory harness? two wires where crossed turned key fired right up?

  • Daddanelena,


    I saw your original post about that, the reason I believe we have different issues is this Jeep ran with first new fuel pump I put in, I had to rebuilt bottom end due to stuck rings and cracked pistons.


    After the rebuild it fired up and ran for 15 minutes or so then I turned it off and have not gotten it to turn back on. I switched the list of parts fuel pump crankshaft cam shaft sensors relays and it is still sitting.


    Thanks for the advice tho.

  • Thanks Meeper,


    I was trying to hold out on pcm being they are costly. You mentioned a used one, may I ask why you say used... would reman or new work?

    I dont know that you can even find a reman one, deff not a new one.


    The light coming on doesnt mean the ECU is working properly, ive seen this before when something just frys inside.


    Does it turn over?

  • Looks like we were ALL WRONG. Not the fuel pump, had two new ones put on. Not the crank nor cam shaft sensors, had new of each put on. Not the relays had new asd and fuel pump relays installed. Not the wiring to pump, was correct as I said.


    Turns out a stuck idle air control valve can cause a crank no start.

  • Haha,


    So I figured it out because I was over it not running. I cranked that thing for awhile then finally the pcm threw iac code, I was able to get it to fire up before I replaced sensor.


    I ended up changing the tps as well because it was having long cranks to fire up.


    Now I think I need to check injectors cus when I prime fuel lines my pressure drops to zero.


    It has a new pump assembly so I’m trying to figure out how to test just from the quick connect back to tank to make sure leak is in rail not pump.


    I’m gonna have to remove the quick connect somehow at rail because the fuel pressure gage I bought does not have connector for the quick connects.

  • damn, thats wild. IF you would have giving it some throttle it probly would have started a while ago and lead you to that fix easier, even though FI i always give some throttle if something doesn't start

  • damn, thats wild. IF you would have giving it some throttle it probly would have started a while ago and lead you to that fix easier, even though FI i always give some throttle if something doesn't start

    "When in doubt, Gas it out"

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