MPG Stinks after front dif and transfer case replacement

[Rocket Man]

The Range AFM delete is on my list but I wanted to make sure my shop couldn't just do it for me before I shell out $200.



You think an o2 sensor/wire could cause such a mpg loss? You know, come to think about it my son walked behind my truck last month and said it smelled rich. hmmm


I also put 37 inch tires on it the same day the T-case was changed....I wonder if that could be.....Im kidding.

Your ECM uses O2 data to determine fuel ratio. If it’s in doubt it will run rich as a safety measure so you don’t burn a piston from being too lean.

 

[iamdub]

The upstream O2s are near the forward prop shaft? I know the downstream ones are and have recent experience with their wires being wrapped around the shaft, but I can't picture where the upstream ones are in relation. If it's the downstream O2s, this would not affect your fuel mixture.

 

[swathdiver]

You think an o2 sensor/wire could cause such a mpg loss? You know, come to think about it my son walked behind my truck last month and said it smelled rich.

The engine relies on them to know whether or not to adjust the amount of fuel delivered to each bank of cylinders. Without such knowledge, they will pump way more fuel to protect the engine. The other downside is that the catalytic converter on that side may soon become damaged and require replacement. Fix it right ASAP. Use OE or mimic the OE wiring as changes in it may affect the readings, fooling the computer because the resistance is too high because of a solder joint or butt connector when there should not be one there.

 

[swathdiver]

The upstream O2s are near the forward prop shaft? I know the downstream ones are and have recent experience with their wires being wrapped around the shaft, but I can't picture where the upstream ones are in relation. If it's the downstream O2s, this would not affect your fuel mixture.

Left bank upper sensor is right above it. Yeah, someone posted photos recently of the same, can't remember or was it Randy?

 

[Jolly Roger]

I've watched a few videos and broke out the Chiltons,...I cant see how on earth the o2 wires would/could ever get close enough to the drive shafts to "wrap" around them. Maybe Im missing something.

 

[Rocket Man]

I've watched a few videos and broke out the Chiltons,...I cant see how on earth the o2 wires would/could ever get close enough to the drive shafts to "wrap" around them. Maybe Im missing something.

Wait...you’ve watched videos and looked at a Chiltons ( crappy excuse for a service manual btw) but haven’t actually looked at your own vehicle where the shop repaired your O2 sensor wires? Any particular reason you haven’t put it on jack stands and had a good look? Maybe see how close the wires are to the prop shafts? All of this conjecture might be resolved with a good visual inspection. Most mechanics are terrible with wiring.

 

[Fless]

Left bank upper sensor is right above it. Yeah, someone posted photos recently of the same, can't remember or was it Randy?

Might have been the one that @iamdub posted, but that was the transfer case encoder wires on the front propshaft.

 

[Jolly Roger]

Wait...you’ve watched videos and looked at a Chiltons ( crappy excuse for a service manual btw) but haven’t actually looked at your own vehicle where the shop repaired your O2 sensor wires? Any particular reason you haven’t put it on jack stands and had a good look? Maybe see how close the wires are to the prop shafts? All of this conjecture might be resolved with a good visual inspection. Most mechanics are terrible with wiring.

I know, I know,...and it pains me to great extent....Long story short..
I used to be a Jeep guy, had a nice garage and any tool you could imagine. ASE certed, engine swaps, custom roll bar fab, suspension fab, you name it I did it all...Got married had kid with medical problems and so many hospital bills I couldn't count em all. Downsized home = No more garage and fewer tools.

 

[Jolly Roger]

Happy 4th guys!
Thank you all who have served our great country!

Did you know the legal separation of the thirteen colonies from Great Britain in 1776 actually occurred on July 2?

.....Reading rainbow music cue...

 

[Rocket Man]

I know, I know,...and it pains me to great extent....Long story short..
I used to be a Jeep guy, had a nice garage and any tool you could imagine. ASE certed, engine swaps, custom roll bar fab, suspension fab, you name it I did it all...Got married had kid with medical problems and so many hospital bills I couldn't count em all. Downsized home = No more garage and fewer tools.

Oh man sorry to hear. Hope you get it figured out.