[RDM]

I have a 2021 GC Trailhawk, 3.6L gas engine. 21,000 km. Runs perfectly and until recently, I never had any starting issues. Now, every once in a while it behaves erratically during start up. One of 2 things occurs. 1. When you press the starter button it will crank over rapidly but won't start, and will just keep cranking. Not even a hint of it catching and trying to start. Hit the button again to stop it, and then immediately hit the button for another start cycle and it starts and runs normally. Or, 2. It will start right away on button press but chugs and vibrates as if it's only running on 2-3 cylinders. Shut it off, and do another quick restart, and again it starts normally and runs fine. It's never done it with the remote start, and only happens when you press the start button. Seems like either no fuel, or not enough fuel. I always keep gas tank fairly full. I get NO fault codes on the OBD scanner. NO other issues at all. BUT, it's starting to happen more frequently, so something is breaking down. Any clues or suggestions are very welcome before I take it to the dealer ? THANKS folks !

 

[jhmace9]

No clue from me but I have a 2021 Trailhawk as well so am interested in what you find.

And no, mine does not do this yet 10000 miles

 

[philbytx]

Back to the dealer for investigation and also document it👍

 

[RDM]

No clue from me but I have a 2021 Trailhawk as well so am interested in what you find.

And no, mine does not do this yet 10000 miles

I'll be sure to post the answer here to help others.

 

[RDM]

Back to the dealer for investigation and also document it👍

For sure I will post outcome here once I find the cause.

 

[Grayloup]

Probably the cps, does it have the check engine light on?

 

[RDM]

Probably the cps, does it have the check engine light on?

A good suggestion, but no, the check engine light does not illuminate, nor is there a fault code on the OBD reader. It should give an error code on that I would think, although I've never plugged my code reader in immediately after the problem happened. I've always been somewhere and done a restart, which perhaps would clear the code before I get a chance to look at them. I'm carrying my code reader with me now everywhere I go, so if it happens again I'll scan for codes before doing a restart !

 

[mdg1978]

A good suggestion, but no, the check engine light does not illuminate, nor is there a fault code on the OBD reader. It should give an error code on that I would think, although I've never plugged my code reader in immediately after the problem happened. I've always been somewhere and done a restart, which perhaps would clear the code before I get a chance to look at them. I'm carrying my code reader with me now everywhere I go, so if it happens again I'll scan for codes before doing a restart !

Hello, 2021 3.6L with the same issue. I have almost 15K miles and the issue started a couple of weeks ago. It will always start fine first thing in the morning and the issue occurs later in the day, after the vehicle has sat unused for a couple of hours. It happened again his afternoon, I pulled out my phone to record it, so I left it trying to start on its own and it eventually started and ran fine for the 30 min drive home. I usually stop it when it acts up, then start it again and it will start without issue. It never happens with the auto start stop function. Almost behaves like the fuel supply has become depressurised and it has to reprime to fuel line to get it to start. No stored error codes after any of the incidents.

 

[RDM]

Hello, 2021 3.6L with the same issue. I have almost 15K miles and the issue started a couple of weeks ago. It will always start fine first thing in the morning and the issue occurs later in the day, after the vehicle has sat unused for a couple of hours. It happened again his afternoon, I pulled out my phone to record it, so I left it trying to start on its own and it eventually started and ran fine for the 30 min drive home. I usually stop it when it acts up, then start it again and it will start without issue. It never happens with the auto start stop function. Almost behaves like the fuel supply has become depressurised and it has to reprime to fuel line to get it to start. No stored error codes after any of the incidents.

Thanks for that MDG. Sounds like we are suffering from the same problem as the starting symptoms are identical. I Also suspect a fuel supply issue, and it could be a fuel pump relay. Mine goes into the dealer tomorrow morning and I will share whatever they find on this forum. Wish me luck !! lol

 

[Wanted33]

I'm curious, so I'm subbed for the fix. Seems like good info to have just in case. Good luck @RDM I hope it's nothing serious.

 

[RDM]

Probably the cps, does it have the check engine light on?

I initially thought that too, but there is NO CIL that ever comes on, and NO fault code from the OBD reader either !

 

[RDM]

I initially thought that too, but there is NO CIL that ever comes on, and NO fault code from the OBD reader either !

Pretty sure that a CPS fault would trigger the CIL, and should also log a fault code in the computer. But, who the heck knows with these new designs??!!!

 

[RDM]

Well folks, I don't have much to enlighten us ! The Jeep was at the dealers all day. They did about 50 start cycles, and of course the problem would not replicate ! They checked all the following: No DTC's. No TSB's from the factory on this issue in 2021's. All relevant relays checked and OK. Fuel rack pressure OK. All frame and engine grounds OK. They even called Jeep Canada engineering for assistance with diagnostics. Nothing. So my plan is to carry my OBD reader with me all the time now, and try to pull a code next time it happens, and before I do a restart. 'Maybe' that will isolate a problem? Fingers crossed that I won't get stranded anywhere ! I might carry a spare fuel pump relay with me since they are cheap and many have suggested that as a likely problem. So, I promise to post again if I find out anything. Thanks to all for your helpful comments. Always appreciated.

 

[RDM]

Well folks, I don't have much to enlighten us ! The Jeep was at the dealers all day. They did about 50 start cycles, and of course the problem would not replicate ! They checked all the following: No DTC's. No TSB's from the factory on this issue in 2021's. All relevant relays checked and OK. Fuel rack pressure OK. All frame and engine grounds OK. They even called Jeep Canada engineering for assistance with diagnostics. Nothing. So my plan is to carry my OBD reader with me all the time now, and try to pull a code next time it happens, and before I do a restart. 'Maybe' that will isolate a problem? Fingers crossed that I won't get stranded anywhere ! I might carry a spare fuel pump relay with me since they are cheap and many have suggested that as a likely problem. So, I promise to post again if I find out anything. Thanks to all for your helpful comments. Always appreciated.

They also did program updates on the PCM and BCM, which might alter control issues on energizing ignition, injectors and possible the fuel delivery hardware. The mechanic didn't think this would really help, but the vehicle was in under warranty so they did it anyway !!

 

[Mogul]

So pure speculation here, but sounds like a similar problem that used to occur on the WJ jeeps long ago. And a poster up above alluded to it. I can't recall the specifics but there was a seal or something that allowed fuel pressure to leak down, requiring extended cranking to rebuild pressure. Not sure if this is your issue, but sounds kind of the same and maybe it wouldn't trip a code. I think remote start "primes" the fuel pump to some extent and maybe reduces the chances of it happening.

 

[RDM]

So pure speculation here, but sounds like a similar problem that used to occur on the WJ jeeps long ago. And a poster up above alluded to it. I can't recall the specifics but there was a seal or something that allowed fuel pressure to leak down, requiring extended cranking to rebuild pressure. Not sure if this is your issue, but sounds kind of the same and maybe it wouldn't trip a code. I think remote start "primes" the fuel pump to some extent and maybe reduces the chances of it happening.

Agreed ! This seems the most plausible explanation to date anyway !! I am laughing at the fact that I am driving around in a nearly new, fairly expensive SUV, and carrying a code reader and a spare fuel pump relay with me. Just in case. lol Bloody hell eh ?!

 

[mjb4450]

I've had this same thing happen to my 2018 Limited 3.6 for the first two years of ownership. I live in Southern Arizona and after a long drive in high temps, once it was parked for 1-2 hours it would crank until it timed itself out. Hitting the start button while it cranked would not stop it. On the second start attempt it would start right up. Seemed like an old style vapor lock problem. It did this on several occasions and then after driving and parking under the same conditions I tried just going through the ACC, RUN, OFF with the start button with my foot off the brake so it would not try to start but the fuel pump would run. The problem never occurred when I did that and the past year and a half with normal starting it has not repeated so it may have fixed itself. Of course now that I mentioned that............... I never went to the dealership because they are not going to follow my instructions on making it recurr. All the service advisors ever hear when a customer talks is bla, bla, ba, bla, then they'll just write down "start problem". I have NEVER had a service advisor write down any detailed info I had for any problem I brought to them. That's why you'll always hear "could not duplicate".

 

[ctnsupra1]

Could be another issue with the TIPM since there aren't any DTCs. There's a fuel relay bypass you can get to circumvent the issue.

 

[JohnAnt]

I have a 2021 GC Trailhawk, 3.6L gas engine. 21,000 km. Runs perfectly and until recently, I never had any starting issues. Now, every once in a while it behaves erratically during start up. One of 2 things occurs. 1. When you press the starter button it will crank over rapidly but won't start, and will just keep cranking. Not even a hint of it catching and trying to start. Hit the button again to stop it, and then immediately hit the button for another start cycle and it starts and runs normally. Or, 2. It will start right away on button press but chugs and vibrates as if it's only running on 2-3 cylinders. Shut it off, and do another quick restart, and again it starts normally and runs fine. It's never done it with the remote start, and only happens when you press the start button. Seems like either no fuel, or not enough fuel. I always keep gas tank fairly full. I get NO fault codes on the OBD scanner. NO other issues at all. BUT, it's starting to happen more frequently, so something is breaking down. Any clues or suggestions are very welcome before I take it to the dealer ? THANKS folks !

Sounds like the fuel pump prime isn’t happening (or at least consistently). I think you can check this by listening for different sounds when starting the engine before it “catches” during a normal start and the aberrant start.

 

[Greg pag]

Sounds like the fuel pump prime isn’t happening (or at least consistently). I think you can check this by listening for different sounds when starting the engine before it “catches” during a normal start and the aberrant start.

My jeep overland is a few years older but was doing something took to dealer. 2400$ later fuel pump was not holding prim. No cheek Engine light