1. Fuel pump on its way out?

    Hi all,
    We bought a '16 Wrangler at the end of last summer with 80k miles on it.

    As soon as the cold weather arrived it developed a stalling issue when cold. It would start and idle fine, but when put into reverse (automatic trans) it will often stall, or nearly stall. It's fine after the car has been driven for a while. It's mainly just after sitting overnight.
    We had it at the dealer for a couple of unrelated items and had them check. No codes shown, and of course it was on its best behavior at the dealer.
    The colder it is, the worse the problem. Recently, there were a few times where it had to crank much longer then usual to even start.

    General online searches reveal many vastly different causes and cures....
    Our neighbor who is a mechanic took a look and uopn hearing / seeing it suspected a fuel / fuel pump issue.
    He bought a tester home from work and checked the pressure the following day. I wasn't there to get numbers, but he said the pressure is definitely low.

    Does this sound reasonable, and are there any other items i should check before subjecting myself to the joy of dropping the tank?

    Thanks.

  2. #2
    Join Date
    Dec 1999
    Location
    Virginia Beach VA
    Posts
    8,000

    Re: Fuel pump on its way out?

    I don't have an answer for you, other than to say when the fuel pump died in my 05 TJ, it was "everything works great", then it was "nothing works at all". I think they tend to die all at once.
    My 2005 Wrangler Build Thread

    “He who is without oil shall throw the first rod.” -Compressions 8.7:1

  3. #3

    Re: Fuel pump on its way out?

    Thanks. Our neighbor who took a look said they sometimes get “ tight” when very cold and don’t pump properly at first, but will act normal after running for a while.

    Personally the last fuel pump I worked on was mechanical and attached to an old Chevy, so I’m hoping for some more info / education. Luckily it’s been a mild Winter here in Jersey with not too many cold spells so it hasn’t been a major headache, but it’s always in the back of my mind that at some point whatever the issue is will eventually come to a head.
    2016 Wrangler Sahara Unlimited.
    Painfully stock... The wife's ride.

  4. #4
    Join Date
    Dec 1999
    Location
    Virginia Beach VA
    Posts
    8,000

    Re: Fuel pump on its way out?

    I drove about half a mile to the bank - everything was normal, turned it off, and tried to start it about 5 minutes later - completely dead. It would crank and crank but never start (or even try to start). I found that starting fluid would get it to sputter. Replacing it was a pain, as it's in the tank on mine (not sure of yours).

    I'd keep my eye out for a check engine code of some sort.
    My 2005 Wrangler Build Thread

    “He who is without oil shall throw the first rod.” -Compressions 8.7:1

  5. #5
    Join Date
    Feb 2009
    Location
    Dayton Ohio Area
    Posts
    5,158

    Fuel pump on its way out?

    There is something else to try. I need to dig it up. But I recall someone with a similar issue a few months back. There is a trans module that can be reset. Or it could be the torque converter.. I'll post back if I find it.


    But, Being your neighbor took the readings he should be able to tell them to you. Otherwise drive to AUto Zone or OReilly's and ask them to borrow the gauge to perform the test. Here is a procedure. The only discrepancy is pressure is 59 +/- 1psi and not +/-5.

    "DESCRIPTION The fuel pressure regulator is located within the fuel pump module. It is serviced by replacing the fuel pump module assembly.
    1. FUEL PUMP MODULE NOTE: Before continuing visually and physically inspect the fuel delivery system for external leaks or damage. Repair/replace as necessary. WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in personal injury or death. Turn the ignition off." Pull fuel pump fuse or relay. Start engine and run until pressure drop causes it to stall. 1min or less. Replace fuses and relay. Repeat this in the end to remove the gauge components"Install special tool #6539 (5/16") or #6631 (3/8") fuel line adapter. Install the fuel pressure gauge. Start the engine and allow the fuel system to reach maximum pressure. Turn the ignition off.
    NOTE: Fuel specification is 407 kPa +/- 34 kPa (59 psi +/- 5 psi).
    Using special tool #C4390, Hose Clamp Pliers, pinch the rubber fuel line between the fuel pressure gauge and the engine. Monitor the fuel pressure gauge for a minimum of 5 minutes.
    NOTE: The pressure should not fall below 241 kPa (35 psi)
    Does the fuel pressure drop? Yes - Replace Fuel Pump Module.
    No - Go To 2
    2. FUEL INJECTOR(S) WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in personal injury or death.
    Remove special tool #C4390. Start the engine and allow the fuel system to reach maximum pressure. Turn the ignition off.
    NOTE: NOTE: Fuel specification is 407 kPa +/- 34 kPa (59 psi +/- 5 psi).
    Move special tool #C4390, Hose Clamp Pliers, from between the fuel pressure gauge and the engine to between the fuel pressure gauge and fuel pump module. Monitor the fuel pressure gauge for a minimum of 5 minutes.
    NOTE: The pressure should not fall below 241 kPa (35 psi) Does the fuel pressure drop?
    Yes - Replace the leaking fuel injectors.
    No - Test Complete.


    DESCRIPTION The fuel pressure regulator is located within the fuel pump module. It is serviced by replacing the fuel pump module assembly.
    1. FUEL PUMP MODULE NOTE: Before continuing visually and physically inspect the fuel delivery system for external leaks or damage. Repair/replace as necessary. WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in personal injury or death. Turn the ignition off. Install special tool #6539 (5/16") or #6631 (3/8") fuel line adapter. Install the fuel pressure gauge. Start the engine and allow the fuel system to reach maximum pressure. Turn the ignition off.
    NOTE: Fuel specification is 407 kPa +/- 34 kPa (59 psi +/- 5 psi).
    Using special tool #C4390, Hose Clamp Pliers, pinch the rubber fuel line between the fuel pressure gauge and the engine. Monitor the fuel pressure gauge for a minimum of 5 minutes.
    NOTE: The pressure should not fall below 241 kPa (35 psi)
    Does the fuel pressure drop? Yes - Replace Fuel Pump Module.
    No - Go To 2
    2. FUEL INJECTOR(S) WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in personal injury or death.
    Remove special tool #C4390. Start the engine and allow the fuel system to reach maximum pressure. Turn the ignition off.
    NOTE: NOTE: Fuel specification is 407 kPa +/- 34 kPa (59 psi +/- 5 psi).
    Move special tool #C4390, Hose Clamp Pliers, from between the fuel pressure gauge and the engine to between the fuel pressure gauge and fuel pump module. Monitor the fuel pressure gauge for a minimum of 5 minutes.
    NOTE: The pressure should not fall below 241 kPa (35 psi) Does the fuel pressure drop?
    Yes - Replace the leaking fuel injectors.
    No - Test Complete."




    Regards,
    JPNinPA

    Sent using TapTalk
    Last edited by JPNinPA; 03-04-2020 at 12:03 AM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  6. #6
    Join Date
    Feb 2009
    Location
    Dayton Ohio Area
    Posts
    5,158

    Fuel pump on its way out?

    From an earlier issue/fix
    Transmission Input shaft & seals, and torque converter replaced. The TCC was sticking and causing die out."

    So a cheap try would be to fully replace transmission oil. Full flush not a drain and replace. Use the correct oil. Being only when cold the oil may be thicker.
    Second replace the TCC solenoid.




    Regards,
    JPNinPA

    Sent using TapTalk
    Last edited by JPNinPA; 03-04-2020 at 12:21 AM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  7. #7

    Re: Fuel pump on its way out?

    The few times that I had a fuel pump die it was proceeded by the pump being noisy for a few days/weeks.

  8. #8

    Re: Fuel pump on its way out?

    Thanks for the input. Sounds like I have a bit to do...
    Then I was thinking yesterday... it's getting warmer. I could theoretically do the work and falsely assume it's fixed until next fall.
    I sometimes miss the carefree old days of simply waiting until something breaks, eliminating guesswork.
    2016 Wrangler Sahara Unlimited.
    Painfully stock... The wife's ride.

  9. #9
    Join Date
    Feb 2009
    Location
    Dayton Ohio Area
    Posts
    5,158

    Re: Fuel pump on its way out?

    Well if it starts again in the winter. Look back at this list and bump the post to the top.

    Flushing the trans is about due anyway at 80k


    Sent from my iPhone using Jeepz.com mobile app
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

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