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New diesel JT - won't start

mack54

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Picked up my new 2022 diesel at the end of August, put on about 1,000 relatively easy miles on the highway / around town over the first 3 weeks.

Finally took it out for a wheeling trip over the weekend and it performed flawlessly. Did about 150 highway miles to the trailhead, and then did about 25 miles on Rattlesnake Canyon trail and a portion of Burns Canyon that runs up into Big Bear. Drove the 150 miles back to LA the next day, and had no issues cruising all the way back, but I did it all in one shot without any stops.

Got back into town and parked it on the street for a few minutes, and then went to re-start it to park it elsewhere. The starter cranks and the main belt is turning, but it seems like there's either no fuel or no combustion. It'll just crank and not actually fire up, and maybe I'm just hearing things, but it sounds unusual while cranking. I let it cool down and tried again, same thing.

I had filled up before I got to the trailhead, so I'd used about 200 miles worth of fuel from the tank before the problem happened so I doubt it's a fuel issue. I'm also using EDT fuel treatment, so hopefully that's nothing to do with it.

Any ideas? I remember reading somewhere that some JTs had issues with wiring harness connectors not being fully seated from the factory, but I can't seem to find it now and otherwise I'm not sure what else it would be. Also doubt it's the fuel pump since it just seems like too much of a coincidence that it didn't croak while driving, only after I stopped it and went to re-start it.

It did get towed to the dealer last night, but I'm not sure how soon they'll look at it.
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Free2roam

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Worst case scenario. Kaboom on the fuel pump. Hoping it's something easier. Cross any water? Could be that dreaded electrical issue.
Check the fuse box? Might have had one rattle loose.
 

@californiajeeping

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When you hit the key do you hear a whine like a fuel pump is running?
 

22EcoDs

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I bet hpfp ..
 
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mack54

mack54

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@Free2roam did not cross any significant water, there were a few muddy spots but I avoided them as I didn't want to have to clean up afterwards :CWL:

@californiajeeping I didn't pay enough attention, I'd have to go back to the dealer and try to start it up again. Does the fuel pump run any time the starter button is in 'run' position, or only when the brake is depressed and the engine is actually started?

Really hoping it's not the fuel pump....I started using EDT from my first fill-up in hopes of holding off a failure until the CP4 recall is rolled out.
 

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mack54

mack54

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Dealer took a while to get to it, but I was able to drop by on Thursday and get them to start checking it out.

According to them, the low pressure fuel pump in the tank failed. No ETA on parts and I'm hoping to get some info about how they confirmed that, but at least (for now) it doesn't seem to be the dreaded HPFP.....
 
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mack54

mack54

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Figured I'd at least post this for other people's awareness and/or to see if anyone has had a similar issue.

2 months in, and the dealer still hasn't identified the problem yet. They've replaced everything related to the low-pressure fuel pump (pump, shorter wiring harness, main wiring harness, powertrain control module) and the pump still pops fuses. They're saying they've checked/tried everything they can think of, and corporate technical resources are getting involved now.

Seems to me like there might be a short or ground somewhere along the way, but if they've replaced the harnesses and the pump itself I'm not sure where else it could be.

I've also started the lemon case with Jeep, I've at least been offered a vehicle repurchase by Stellantis and am still waiting to see what the cash compensation would be for this ordeal. I'm thinking I might be selling this thing back, but since interest rates have gone up I'm not sure I'd want to purchase another new Gladiator to replace it :(
 

Camaroboi13

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Sounds very similar to the problem the 2021 JTD was having that I almost purchased. They kept telling me the fuel pump was being replaced under recall and they couldn't let it leave the lot until it was done. I had already put a deposit on it. They got the new pump and said it wasn't responding to the PCM. So when they replaced the PCM and attempted to start it, it actually fried the PCM. Unfortunately I was already on my way out to pick up the vehicle across state lines, so they had to come correct on a 2022 instead. Worked out in my favor at least. They told me that the 2021 would end up being a buy back from Mopar and it would likely sit on their lot for 6 months before moving. It was silver too... just throwing some superstition out there lol
 
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mack54

mack54

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4 months later - finally have an update worth posting. Here's the recap of the troubleshooting they performed / what they replaced:

  • Vehicle received in no-start condition - removed fuel line feeding the high-pressure fuel pump and verified no flow coming to HPFP.
  • Fault code detected, replaced lift pump (low-pressure fuel pump) fuse - fuel pump fuse popped
  • Reseat & verify lift pump connection - fuel pump fuse popped
  • Verified no contamination in the fuel filter / fuel quality solenoid
  • Installed new lift pump module - fuel pump fuse popped
  • Temporarily ran new wire from power distribution center to fuel pump - fuel pump fuse popped
  • Replaced 'dash to light' wiring harness (not sure what this is) - issues with powertrain control module after this
  • Replaced powertrain control module - fuel pump fuse popped
  • Replaced main wiring harness (frame rail wiring) - required cab to be removed from frame
  • Replaced lift pump (2nd time replaced)
  • Aux battery failed battery test, replaced
  • Vehicle starts

TLDR - the low pressure fuel pump kept popping fuses, they replaced it but the issue still kept occuring. They eventually determined the main wiring harness had an issue (probably a short), and replaced that. Unfortunately, the old main harness had blown up the replacement fuel pump - so once the new harness and a 2nd new fuel pump were installed, the issue was resolved.

Now it's time to decide what to do with the vehicle - I'm waiting on Jeep customer care to tell me what compensation they'll offer me to keep the vehicle, and then I'll decide what to do from there. The dealer seems semi confident they found the real issue (main harness failure), but I'm still unsure of how confident I'll be taking the Jeep out to remote places after this ordeal....
 

IPRoutes

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4 months later - finally have an update worth posting. Here's the recap of the troubleshooting they performed / what they replaced:

  • Vehicle received in no-start condition - removed fuel line feeding the high-pressure fuel pump and verified no flow coming to HPFP.
  • Fault code detected, replaced lift pump (low-pressure fuel pump) fuse - fuel pump fuse popped
  • Reseat & verify lift pump connection - fuel pump fuse popped
  • Verified no contamination in the fuel filter / fuel quality solenoid
  • Installed new lift pump module - fuel pump fuse popped
  • Temporarily ran new wire from power distribution center to fuel pump - fuel pump fuse popped
  • Replaced 'dash to light' wiring harness (not sure what this is) - issues with powertrain control module after this
  • Replaced powertrain control module - fuel pump fuse popped
  • Replaced main wiring harness (frame rail wiring) - required cab to be removed from frame
  • Replaced lift pump (2nd time replaced)
  • Aux battery failed battery test, replaced
  • Vehicle starts

TLDR - the low pressure fuel pump kept popping fuses, they replaced it but the issue still kept occuring. They eventually determined the main wiring harness had an issue (probably a short), and replaced that. Unfortunately, the old main harness had blown up the replacement fuel pump - so once the new harness and a 2nd new fuel pump were installed, the issue was resolved.

Now it's time to decide what to do with the vehicle - I'm waiting on Jeep customer care to tell me what compensation they'll offer me to keep the vehicle, and then I'll decide what to do from there. The dealer seems semi confident they found the real issue (main harness failure), but I'm still unsure of how confident I'll be taking the Jeep out to remote places after this ordeal....
Drive around in civilization for 500 - 1000 miles or so. If no issues, it will rebuild your confidence in it.
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