Poor mileage after tune

I am new to hp tuners and have a lot to learn but do enjoy learning although it's tougher in my mid 50's. :confused: I have a 2010 Jeep Wrangler with a 2013 LMG 5.3/6l80 that I recently had "professionally" tuned and I am getting horrible fuel mileage after the tune. After the swap (before the tune) I had been getting around 17 on the highway but now cannot break 13mpg, which is about what it does in town and that is driving it conservatively. It has plenty of power, starts and runs great and works well offroad, no complaints about anything but the fuel economy. Can someone take a look at the file I pulled tonight and let me know what might be wrong?
please and thank you,

Jeff

Your data log is missing lots of stuff. Without o2 sensors and fuel trims it's hard to see what the fueling like.

What size tires and gear ratio are you running? The tune says 31's and 3.42's. If that is wrong that will throw of the transmission shift points and torque converter settings.

How much emissions equipment is still on here? Like cats and rear o2 sensors?? Some things are still left on if those are gone.


The MAF curve has way more fuel in it than a stock file I have for a 2012 Silverado. Are you running the stock air box or a custom intake tube??


In all honestly they hardly changed anything in that tune. Basically zero transmission tuning for better shifts and better torque converter settings to help the transmission live longer.

Looks like only the MAF was changed, VVE is untouched.

Somebody did something very weird to the IAT table, changed the axis to span about half the resistance range as the stock one. Are you using the original '13 Suburban MAF?

Thank you for the reply, this is a Motech style swap sold through Overland Performance. It did log more info before the tune so I was curious if he had disabled the O2's?

The Jeep has 4.10's and 35" tires which was adjusted before the swap with an obd jscan tool and the speedo is right on with a gps. John at OP said I was good to leave that as is.

All the emission stuff is there, cats and 4 - O2's, switched to the more efficient GM evap system, supposed to be able to pass emissions but it is not an issue here in KS.

I do have an AFE cold air filter that was pulling hot air from under the hood but I have since created a nice box that seals out the hottest air and pulls in cooler air from the front corner. I compared an earlier tune with what it has now and I agree not much was changed. They did fix my throttle hang issue which is why I finally stopped jacking with it and took it there but the fuel mileage part is getting old. everything else about it is perfect very fun to drive and I have put over 12k miles in the last year. I would drive it anywhere, unless gas keeps going up....

Quote:

---

Are you using the original '13 Suburban MAF?

---

No, it is a new one that came with the swap kit. I see lots of things that are different than the original file but I just don't have the knowlege to put it all together and understand how to make it better.
It is pretty cleat to me though that it isn't right. Like I said it starts and runs great, no knock or ping and I have the power to pass easily out on the highway. its just a gas hog.

Your maf is showing more airflow than both my stock and tuned 2011 6.2L's in both Sierra and Caddy brands....

Looks like all they did was add timing to the PE region and smooth it. In what would be the cruise region it's not that bad.

Tuning your MAF and VVE will make a HUGE difference in feel and fuel economy.

Your AFR is set a 14.2 across the board, with FF enabled. Your PE was changed to 1.2, or 11.8....fixing the Stoich AFR and tuning the MAF/VVE will make the biggest differences in fuel consumption, unless you're running E10 all the time.

There's a great thread in this section on tuning your MAF and VVE with NB's. Just remember to let it sit or drive 10-15minutes before logging to not log the 'rich after flash'. You can't tune your PE with this method, but you're focused on cruising currently.

Thank you for the replies. I did go out today and did some logging and came up with a much better file.

When you look at the logs, look at the fuel trims. See how often they are are like -20% when you are cruising at 40-45mph, that is the o2 sensors trying to remove fuel the best it can.

That is where some of your fuel mileage is going.

Not having a wideband makes this tougher because we can't get it exact for wide open throttle but you can still use the fuel trims for part throttle. I would highlight the 0-6,000hz range of the MAF curve and remove 5% worth of fuel just to see what it does to the fuel trims. If they drop to -10%, we are going in the right direction. Then slowly work/dial the fueling back in that area.

I did change several things.
I removed 5% on the MAF curve as you suggested

Based on a couple other comments
I changed the power enrich delay rpm to 5000 from 100
changed the power enrich eq ratio (gas) to the original stock values
changed the general\ stoich afr to the original stock values

Don't notice much difference with how it runs but I would say the fuel trims look much better and I did reset them before this drive. I have a wideband coming and will figure this out and tune the maf and ve properly but do you think this will improve anything or am I making it a bigger mess?

Thanks again for the help and comments.