94 Jeep Grand Cherokee Laredo Fuel Problem

Discussion in 'Other Repairs' started by Abu, Dec 25, 2005.

  1. Abu

    Abu New Member

    Messages:
    248
    State:
    Hemlock,Ohio
    My 94 Grand Cherokee with a V8 decided to stall on my wife and would not start again. I had it towed to my house. Turned the key and it fired right up but died after about 15 minutes. It will start sometimes and run fine but not for any length of time and other times it will not get any fuel at all and won't start. It will always start when I spray starting fluid in it until it burns all the starting fluid so I know I have good spark. I changed the fuel filter located on the drivers side frame and it was of no help. I keep thinking it may be the fuel pump but everytime I have seen a fuel pump go out it was completely out and there was no starting at all. Anyone have any ideas before I take it in for repair I would really appreciate it. I try to fix everything myself but this one is beyond me.
    Abu
     
  2. Deltalover

    Deltalover New Member

    Messages:
    1,227
    State:
    Tracy Calif
    I have an older jeep cherokee, 1989! One day I filled it up and it would not start, I came back about 2 hrs later and it started right up and ran for several monthes, and then again same thing. I finally changed the filter on the drivers side, in the rear by tank. Havent had any problem for 2 years. May or maynot help you. Good luck!
     

  3. davesoutfishing

    davesoutfishing New Member

    Messages:
    479
    State:
    Menominee Michigan
    try replaceing the fuel relays
     
  4. Phil Washburn

    Phil Washburn New Member

    Messages:
    7,680
    State:
    Shawnee OK
    sounds like it's fuel pump time
     
  5. Cattracker16

    Cattracker16 New Member

    Messages:
    356
    State:
    Wilton Iowa
    If it's a fuel delivery problem.. and runs for 15 minutes.. i'd almost think ya have some plumbing problem.. no fuel leaks? maybe some "crap" in fuel tank. or it's time for fuel pump... have u drained fuel tank to see if there is some "crap" in tank?.. if u have some rubber inline some where or can plumb in a auxillary pump i'd try that.. and no mo starting fluid... if it's the fuel pump in the tank break the line loose and see if it's pumping losta fuel it should spray a long ways maybe 4 to 5 feet.. this is jus my opinion..
     
  6. jason454ci

    jason454ci Active Member

    Messages:
    1,307
    State:
    Zanesville, Ohi
    Abu, sounds to me like the fuel pump is the problem. You want to be sure that is the problem before you replace it. The fuel module for that thing probally isn't real cheap. When it won't start you need to check for power going to the fuel pump. To do this you need a 12 volt test light or volt meter. You will need to find the connector located in front of the fuel tank, should be 4 wires or so. Hook one end of the test light to a good ground like the transfer case. Unplug the connector and find the dark green wire with a white stripe on it in the end of the harness going into the body of the vehicle. Have someone turn the ignition switch to the run position. You should have power for 2 seconds then it will go off. Then have them crank the engine it should have power continuiosly. If you do have power then the pump is the problem. If no power then I would say it is a relay. Make sure before checking this that the problem is there and it will not start. If you have any questions just let me know.
     
  7. Tee

    Tee New Member

    Messages:
    56
    State:
    TN
    We had a simular problem on Kat's jeep. Tested the pump, it was bad. replaced the pump with one from the Jeep dealer, it lasted about 2 months.
    The jeep dealer made the pump good under their parts warranty, I changed it out and it lasted for about 2 months again.

    Finally bit the bullet and had it towed to our local dealer. They checked it and said the "fuel pump was bad, AND it had the wrong pump in it". When I showed them the invoice from their parts department, they "decided" that we need a new wiring harness for $1200.00.
    Needless to saw I "explained their sunday school lesson to them", towed the Jeep home, DID NOT pay them a dime, and started checking grounds. After about 30 hours (literally) of checking grounds and cleaning contact points, I found a loose ground wire that was causing the pump to burn up from high resistance.

    I did have to replace the pump again (under warranty) but the jeep continued to run without a hitch for another 70,000 miles. It would still be running except for the fact that at around 300,00 miles it has a "slight knock from the crankcase"............
     
  8. Cyclops01

    Cyclops01 New Member

    Messages:
    578
    State:
    Eden, NC.
    Check the crankshaft position sensor. It determines the timing for the fuel injection and cylinder ignition. When it fails, it can create all of the classic symptoms of fuel pump failure but, after a few minutes, the engine will fire and run until the sensor fails again... minutes, hours later

    It's an inexpensive part and easy to change out (one bolt, one quick connector) but it's one of those "mystery" parts that some shops might convince you is a couple hundred dollar job.

    Mike
     
  9. Abu

    Abu New Member

    Messages:
    248
    State:
    Hemlock,Ohio
    I have already replaced the fuel filter twice and the crank position sensor. I am sure I will figure it out with all the great advice. Sounds like some of you have been down this road before. Tomorrow is supposed to be in the 50's here and I will get out the meter to begin with. If the fuel pump is getting the correct voltage I will pull the filter and have someone crank the key to see if it is spraying fuel. Sooner or later I will narrow it down. Thank all of you for all of your help. This website is great with everyone helping each other out. I will also leave the cigarettes in the house and make sure the vehicle has not been started to heat up anything before I perform the tests. :) Abu
     
  10. Cyclops01

    Cyclops01 New Member

    Messages:
    578
    State:
    Eden, NC.
    John,

    There is a posibility it is the output pressure from the fuel pump. Once the engine is at normal operating temp, the fuel pressure may not be enough to keep it going. It should be pushing around 31 to 33 psi with the regulator vacuum hose attached or, 39 to 41 psi with the hose disconnected.

    Pulling the hose to see if there's flow only tells you IF there's flow, not the required pressure. You will have to use a high pressure fuel gauge to be certain.

    Mike
     
  11. Abu

    Abu New Member

    Messages:
    248
    State:
    Hemlock,Ohio
    Thanks Mike. I am going to print everything out and it looks like I will be borrowing some tools and help from my brother inlaw tomorrow afternoon. John
     
  12. Abu

    Abu New Member

    Messages:
    248
    State:
    Hemlock,Ohio
    One thing that may be of importance. I forgot to mention the onboard computer in the dash always comes up with the message COOLANT SENSOR BAD. I replaced the coolant sensor and the message will not go away. It has ran fine for over two years with the message displayed on the dashboard computer. John
     
  13. Cyclops01

    Cyclops01 New Member

    Messages:
    578
    State:
    Eden, NC.
    John,

    I'm not sure if the 94 is OBD II compliant. If it's not, you should be able to clear any memory stored trouble codes by disconnecting the battery for a few minutes. That shouldn't have anything to do with your present problem though.

    That's the pain with all vehicles built prior to OBD II compliance. You have to find a code scanner for the particular model of vehicle or go by trial and error. And that gets expensive.

    I'll say this; I love the Jeeps. I'm 6' 4" and 330 pounds but I can still crawl under one and do most repairs without using a jack or stands. And most everything is easy to get at.

    Let me know how it goes.

    Mike
     
  14. davesoutfishing

    davesoutfishing New Member

    Messages:
    479
    State:
    Menominee Michigan
  15. Mutt

    Mutt Administrator Staff Member Supporting Member

    Messages:
    18,499
    State:
    Ca
    Name:
    Mutt
    also check the fuel pump relay make sure the grounds are good check the computer out there are lots of varying factors that can cause issues with it.
     
  16. coalminer78

    coalminer78 New Member

    Messages:
    102
    State:
    Lincoln, IL
    sounds like your fuel pump is overheating causing it to stop pumping
     
  17. Abu

    Abu New Member

    Messages:
    248
    State:
    Hemlock,Ohio
    Wish I could say I got lucky but I never. It is definitely the fuel pump. Done every test known to man and the fuel pump is the culprit. I have a manual and I am going to attempt tearing it apart myself and replacing the fuel pump. Had no idea the fuel pump module would be over $200 everywhere I checked. Only wish it was easier to get to, looks like plenty of parts to remove before I can even get to removing the fuel pump. Wish me luck or give me a good labor estimate. :)
    Abu
     
  18. Cyclops01

    Cyclops01 New Member

    Messages:
    578
    State:
    Eden, NC.
    John,

    You can do it, just take it a step at a time and have a solid system to support and lower the fuel tank. Any fuel in the tank is going to add six and a quarter pounds per gallon.

    Good luck.

    Mike
     
  19. jason454ci

    jason454ci Active Member

    Messages:
    1,307
    State:
    Zanesville, Ohi
    Abu those fuel pumps are one of the easier ones to do. Take off the filler and vent hoses, unplug the wiring, and undo the lines at the top of the module. You may have to drop the take a little to get to the ones on top of the tank. Use a hammer and nut driver or something dull to unscrew the plastic ring that holds the module in. Be very sure to get the threads started right when reassembling it. I have seen them get started crooked the fly off a little while later. Just take your time you will be fine. If you have any questions feel free to call me at 740-408-0544.