New fuel pump issues after recall

[HugoStiglitz]

Has anyone had a recent fuel pump replaced for their 3.0 eco diesel JL? Had it done last December (2023) and my mpg went from 26 to 18/19. The range for a full tank went from 460 ish to around 320. Anyone else have these issues?

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[BDinTX]

Has your driving changed at all? I had a floor plug fell out and I thought something was wrong with the engine. So I kept accelerating then coasting and my mileage went down quite a bit reinforcing my thinking something was wrong. Found and replaced the floor plug, sound went back to normal, I stopped messing with the skinny pedal, MPG went back up. I've been holding pretty steady at 21.5 MPG with 37" mud tires. Didn't change after the HPFP was replaced. Welcome to the forum.

 

[jludave]

Has anyone had a recent fuel pump replaced for their 3.0 eco diesel JL? Had it done last December (2023) and my mpg went from 26 to 18/19. The range for a full tank went from 460 ish to around 320. Anyone else have these issues?

Have you tried recalibrating the throttle/gas pedal?

1. Turn the ignition to ON but not START
2. Wait for all warning lights to go out, except for the Check Engine Light
3. Slowly press the accelerator pedal to the floor
4. Slowly release the accelerator pedal
5. Turn the ignition to OFF
6. Start the engine

 

[HugoStiglitz]

Has your driving changed at all? I had a floor plug fell out and I thought something was wrong with the engine. So I kept accelerating then coasting and my mileage went down quite a bit reinforcing my thinking something was wrong. Found and replaced the floor plug, sound went back to normal, I stopped messing with the skinny pedal, MPG went back up. I've been holding pretty steady at 21.5 MPG with 37" mud tires. Didn't change after the HPFP was replaced. Welcome to the forum.

Driving hasn’t changed and I usually have the cruise control on the way to work. I checked and nothing seems out of place. Thanks for the welcome!

Have you tried recalibrating the throttle/gas pedal?

1. Turn the ignition to ON but not START
2. Wait for all warning lights to go out, except for the Check Engine Light
3. Slowly press the accelerator pedal to the floor
4. Slowly release the accelerator pedal
5. Turn the ignition to OFF
6. Start the engine

just tried this and it looks like that may have helped! I’ll give it a few days to see if it fixes it and will update you. Thanks again!

 

[garykk]

I had the fuel pump change a few months ago, nothing has changed, still getting around 26 mpg .

 

[2023reignitin]

I didn't have the mpg issue after I had my HPFP recall addressed, but now, every time I turn the Jeep off I hear a loud whine for a few minutes. Anyone else have this issue? Wondering if I need to take it back and have it checked out.

 

[dgeist]

I didn't have the mpg issue after I had my HPFP recall addressed, but now, every time I turn the Jeep off I hear a loud whine for a few minutes. Anyone else have this issue? Wondering if I need to take it back and have it checked out.

I've had that since day one (although I wouldn't call it "loud"). Anecdotally others have suggested both that it's DEF being pumped back to the tank OR that it's a automatic fluid circulation going through the turbo to assist in post-shutdown cooling. Frankly I'm okay with either of those. I idle for about a minute minimum whenever I stop the vehicle anyway.

 

[2023reignitin]

I've had that since day one (although I wouldn't call it "loud"). Anecdotally others have suggested both that it's DEF being pumped back to the tank OR that it's a automatic fluid circulation going through the turbo to assist in post-shutdown cooling. Frankly I'm okay with either of those. I idle for about a minute minimum whenever I stop the vehicle anyway.

Thank you! This makes sense... I didn't even think about the DEF cycling back either. This is the first diesel I've owned that required DEF and I'm still adjusting to it. Thanks for responding so quickly! I appreciate the info!

 

[dgeist]

Thank you! This makes sense... I didn't even think about the DEF cycling back either. This is the first diesel I've owned that required DEF and I'm still adjusting to it. Thanks for responding so quickly! I appreciate the info!

Same. My other jeep is a 2005 KJ CRD and it's just like driving around a VM Motori tractor...with normal tractor sounds and very minimal emissions controls. The turbos in those DO like to implode after a good run, though. I learned my lesson with EGT cool down LONG ago.

 

[Gorilla57]

I've had that since day one (although I wouldn't call it "loud"). Anecdotally others have suggested both that it's DEF being pumped back to the tank OR that it's a automatic fluid circulation going through the turbo to assist in post-shutdown cooling. Frankly I'm okay with either of those. I idle for about a minute minimum whenever I stop the vehicle anyway.

It is neither of those. I’ve linked to the TSB a couple of times already, it’s the electric fuel pump circulating fuel through the CP4.

 

[dgeist]

It is neither of those. I’ve linked to the TSB a couple of times already, it’s the electric fuel pump circulating fuel through the CP4.

Oh, that's pretty interesting. Thanks.

My purchase was new post-recall, so it's always been there for me. I guess the idea is that heat related issues on the CP3 were a portion of the cause of the failures? (although I'm not sure exactly how heat would cause the lobes to get misaligned and grind or how cooling them would help...)

 

[zouch]

not sure where you linked that, but i don’t see anything from you in this thread.

does it really say the noise we hear under the hood is from the Electric Fuel Pump that’s all the way back in the Fuel Tank?

It is neither of those. I’ve linked to the TSB a couple of times already, it’s the electric fuel pump circulating fuel through the CP4.

 

[Gorilla57]

not sure where you linked that, but i don’t see anything from you in this thread.

does it really say the noise we hear under the hood is from the Electric Fuel Pump that’s all the way back in the Fuel Tank?

I didn't link it, people can search for themselves. But since you asked:

https://www.jlwranglerforums.com/fo...-buzzing-after-the-vehicle-is-shut-off.71139/

 

[Muttbus-JL]

Have you tried recalibrating the throttle/gas pedal?

1. Turn the ignition to ON but not START
2. Wait for all warning lights to go out, except for the Check Engine Light
3. Slowly press the accelerator pedal to the floor
4. Slowly release the accelerator pedal
5. Turn the ignition to OFF
6. Start the engine

Genius advice here, and if we ever cross paths, I owe you a beer or three! Thanks for the check engine light elimination explanation!
pete

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