New owner / mpg questions

[downforce137]

How dos the truck know how to trim fuel with nothing downstream? Hook up a scanner and look at your Afr % and report back.

the downstream sensors in all vehicles are only for catalyst efficiency monitoring.. they have no affect on fuel trim...

downstream means downstream of the catalyst.. the upstream of the catalyst sensors are for adjusting the fuel trim...

the cat burns off the unused portion of the combustion process, and while the exhaust will smell much different from a vehicle with a catalyst, the downstream o2 is only for on board diagnostics and check engine light things for emissions monitors... thats their only purpose..

 

[downforce137]

obviously it has some custom HPtuners things done to the ECU... id find a dyno tuner in your area and see what they can do...

 

[JesBdx]

@cptnslo Not sure if there's a tune or not. Something was done though bc I'm not throwing a code for the deleted o2 sensors.

 

[downforce137]

@cptnslo Not sure if there's a tune or not. Something was done though bc I'm not throwing a code for the deleted o2 sensors.

yeah..they were turned off in HPtuners from being able to run their tests, and have priority to turn on the check engine light..

 

[TAC71]

Normally I get about 14.5mpg or so. Towing my travel trailer...5000lb... I get about 10 mpg and that's always doing speed limit or more.

 

[JesBdx]

Jeez...14.5? That's over an extra 100 miles a tank for me.

 

[TAC71]

Just did a 600 mile run on tuesday 95% on highway. A lot of big hills and 75mph. Got 14.8 mpg.
Gotta get acceptable mileage when our gas runs about $ 7 a gallon

 

[JesBdx]

That's good mileage. I'm working on the right combo to get mine back up...yeah definitely with gas prices like they are now

 

[WHBD]

Seems pretty off. I have 231k on mine and it's stock exept for a JDM 93 tune. I towed a fully loaded 28ft enclosed trailer from CA to VA and averaged 9.6mpg...I average 14.5 in mixed highway and city normally. And typically average around 17mpg going to visit my folks in VA on a 400 mile trip each way. but I take advantage of the hills to do that.