Bad mileage after fuel pump recall?

[djthumper]

Jeep Only, it has been a while since I have checked. Prestige has reached out to me but I am not fond of some of the work they have done when I couldn't get into Jeep Only. I tried going to Jim Marsh a couple of times with my other jeep and was not impressed.

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[Kintama40]

Is anyone experiencing terrible fuel mileage after the Hpfp recall? I was consistently getting 17 mpg around town and 20 highway, but since the recall i can’t get 13mpg in town and struggle to get 16 highway. This is based off of hand calculations. I’m not ruling out the possibility of winter blend fuel being the culprit but I’ve never had such a drastic change with the fuel in any diesel truck I’ve owned. Anyone else seeing this?

My fuel economy has decreased by 1.5mpg since the recall. They must have flashed something…

 

[Escape.idiocracy]

I dropped 3mpg. Glad this was posted… what’s kind of crazy is there isn’t a software flash that goes along with the pump replacement…. So, that really doesn’t help with making the “why” make sense.

We have put 3k miles on since the pump replacement… economy isnt picking up with time either… lol

 

[Kintama40]

I dropped 3mpg. Glad this was posted… what’s kind of crazy is there isn’t a software flash that goes along with the pump replacement…. So, that really doesn’t help with making the “why” make sense.

We have put 3k miles on since the pump replacement… economy isnt picking up with time either… lol

I have 2 friends with diesels and they are saying the same thing, they lost MPG after the swap. I’m still doing better than my gasser friends, but the margins are pretty close now.

 

[Rusty PW]

I haven't lost any mpg since the recall.

 

[Ericshere03]

Interestingly, I bought a ‘23 Gladiator Diesel built 11/23 which presumably has the new pump from the factory and seeing far less MOG than my 21 80th anniversary. In fact my stock rubicon with stock 33” MT tires is about dead even with my previous overland with Mopar lift and 37” BFG AT.

I’ll be doing the 37” and Mopar lift here shortly, I really REALLY hope it doesn’t sink even lower.

I wonder if GDE has any insight. I been meaning to call them to order up a tune.

in a diesel fuel quantity should be dead on because of the wide and o2 sensors. HOWEVER the timing can be slightly off and effect power and efficiency. So perhaps there is something inherent with the new design that affects timing or they’re being installed slightly off time.

Then again, the computer may have the smarts to adjust anyways… just a thought

 

[TheSolarWizard]

I swear I must be the last MF on the list for the recall ?‍

No you definitely are not. Unfortunately

 

[Schaft]

I definitely noticed a decrease in fuel economy, after the fuel pump recall change. Between 1–2 MPG. Especially in colder weather and driving local.
In a previous post, I spoke of the P026C check engine light scan. I added hot shots, diesel extreme, cleaner and conditioner. So far, that has helped my fuel economy, and the light hasn’t come back on.
That said, I had heard, they were intentionally changing the PCM tune, during the recall, to help with crankshaft issues the 3.0’s were having.
While under warranty, Oct. 2023, I had to have both batteries changed, as well as the Z tray. For those that don’t know, that it is a fuse cluster, outside the fuse box, that connects your electrical system, to the fuse box. Please excuse the technicalities. I’m not a mechanic. During that visit, the technician stressed at least three times, that my warranty on the engine and drivetrain, would be voided, if I change the tune on the PCM, in anyway. That makes me believe there is truth, to the PCM tune change, because of the crankshaft issues. Again, the fuel economy is better, but not as good as before recall

 

[Rusty PW]

I definitely noticed a decrease in fuel economy, after the fuel pump recall change. Between 1–2 MPG. Especially in colder weather and driving local.
In a previous post, I spoke of the P026C check engine light scan. I added hot shots, diesel extreme, cleaner and conditioner. So far, that has helped my fuel economy, and the light hasn’t come back on.
That said, I had heard, they were intentionally changing the PCM tune, during the recall, to help with crankshaft issues the 3.0’s were having.
While under warranty, Oct. 2023, I had to have both batteries changed, as well as the Z tray. For those that don’t know, that it is a fuse cluster, outside the fuse box, that connects your electrical system, to the fuse box. Please excuse the technicalities. I’m not a mechanic. During that visit, the technician stressed at least three times, that my warranty on the engine and drivetrain, would be voided, if I change the tune on the PCM, in anyway. That makes me believe there is truth, to the PCM tune change, because of the crankshaft issues. Again, the fuel economy is better, but not as good as before recall

Any tune will void the warranty.

What is this crank shaft problem? Never heard of it.

When they did my fuel pump recall. They never plugged into the under dash port. I asked if they were going to do any ecu changes, and they said no.

 

[Schaft]

https://www.ecodieselram.com/forum/threads/gen3-still-same-issue-crankshaft-positioning-sensor.4826/

 

[Rusty PW]

https://www.ecodieselram.com/forum/threads/gen3-still-same-issue-crankshaft-positioning-sensor.4826/

Yeah.... the sensor issue. Thought there was something else going on with the crank it's self.

 

[RoamingGladiator]

I'm seeing better fuel mileage after my HPFP replacement funny enough. I'm getting absolutely insane fuel mileage on 37s.

20mpg (12L/100km) strictly around town, lots of stop lights
28-32mpg (7-9L/100km) on the highway doing about 65-70mph (105-110km/h)

 

[69charged]

I bought mine with the new pump already installed, so I have no numbers to compare to. I installed 35" Duratrac's when it had 700kms on it, and a 1.5" level. I show on the dash around 18-20mpg consistently. I have corrected for tire size difference with JSCAN, and have not hand calculated yet. I currently have 15,000kms on it now since January 20th. I was thinking the mileage would have been better, but maybe a re-flash after the pump install made it worse?

 

[Kintama40]

I bought mine with the new pump already installed, so I have no numbers to compare to. I installed 35" Duratrac's when it had 700kms on it, and a 1.5" level. I show on the dash around 18-20mpg consistently. I have corrected for tire size difference with JSCAN, and have not hand calculated yet. I currently have 15,000kms on it now since January 20th. I was thinking the mileage would have been better, but maybe a re-flash after the pump install made it worse?

Before the pump change I was getting 21.5 mixed on 37s. Now I’m at like 18-19 mixed. I knew I should’ve just kept the old pump in there. Next time I will listen to the voice in my head.

 

[3VOLVE]

Mine dropped 3-4 mpg and I took it back to the dealership. They performed a software update and was right back where I was prior to the swap. I have noticed my highway mpg is up 1-2 mpg.

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