Why does my MPG improve after resetting the ECM?

[Mudderoy]

I've noticed that my mpg seems to increase each time I reset the ECM. I believe it was Payless 4x that told me that basically this sets the ECM back to it's default setting and it begins to "re-learn" it's dynamic settings. Based on how I drive, etc...

I also seem to remember that he said I may be getting bad information from a sensor.

Well it's not a guarantee but each sensor has been replaced.

Since I downloaded this program for my phone...

http://youtu.be/Ay-ZvTn3fLo

I'll be resetting my ECM daily to see what the REAL results to MPG are. Right now it's just what I see on the fuel gauge. So I may be incorrect in my perception.

I use an ELM-327 blue tooth OBD II reader to connect to the OBD II port in my Jeep. That is HOW this software connects to and reads/collects/displays the information. It was about $55 a couple of years ago.

[Mudderoy]

Sensors changed (I'm sure I'll forget something)

O2 (upstream and down, Bosch about 4 years ago)
O2 (upstream, Chrysler part!, about a year ago)
IAC
TPS (twice)
CKS (in the distributor)
MAT
CPS (Something wrong with the new one, re-installed the old one)
IAT
Temp Sensor (put old one back as this one read higher)

Cleaned throttle body (twice) Second time I took it off completely and hosed it down in brake cleaner.
Injectors!

I know I have a problem with the fuel pressure regulator, but the fuel pump is providing about 49.5 psi while the engine is running.

Spark plugs, wires, cap, rotor have all be changed several times. Probably time to change the plugs again. I'll probably do this when I get a new Chrysler CPS because I want to set the gap wider. I have a Performance Distributor 4.0 kit and I was having problems with it and the old (NEW non-OEM) CPS.

Based on old OBD II collected data the O2 sensors seem to be running rich. Between .6 and .8 volts at highway speeds (upstream sensor).

Had a crack in the exhaust manifold, replaced that a few years ago.

Keep in mind everything has been done in the last 4 years.

Oh CAT and muffler where changed also.

[TeXJ]

how much is the MPG off?

You said you changed your muffler...changed it to a High flow like a flowmaster or something?

Do you have a highflow air intake? K&N cone filter or drop-in?

[Mudderoy]

how much is the MPG off?

You said you changed your muffler...changed it to a High flow like a flowmaster or something?

Do you have a highflow air intake? K&N cone filter or drop-in?

CAT is just a new one, and yes a flowmaster muffler.

MPG didn't change before or after any of the modifications.

Air intake is stock. I'm not going to put something on the intake that just makes it easier for water to get sucked in. I should be doing a snorkel soon though.

[TeXJ]

how far off are you on your MPGs?

[Mudderoy]

how far off are you on your MPGs?

Well I'm not sure. I've only been measuring it since I have had the lift and the tires. It was 10.8 when I first started, but increased by 2 mph when I got the 4.56 gears installed. Since then it's been between 11.6 and 13.2 mpg.

From what others with 97+ and similar set ups they are claiming 16 to 18 mpg otherwise I would just have accepted that it costs mpg to have a modified 4x4.

:sign0181:

[TeXJ]

Well I'm not sure. I've only been measuring it since I have had the lift and the tires. It was 10.8 when I first started, but increased by 2 mph when I got the 4.56 gears installed. Since then it's been between 11.6 and 13.2 mpg.

From what others with 97+ and similar set ups they are claiming 16 to 18 mpg otherwise I would just have accepted that it costs mpg to have a modified 4x4.

:sign0181:

I was getting ~19mpg when mine was stock. Then I went around the ~10mpg with 33's and 3.55 gears. Now with 4.56s, not sure yet as I have yet to really check it. Although I know it is MUCH better. But to get 18mpg with a lifted jeep,...seems questionable. Did they have winches and bumpers like we do?

[Mudderoy]

I was getting ~19mpg when mine was stock. Then I went around the ~10mpg with 33's and 3.55 gears. Now with 4.56s, not sure yet as I have yet to really check it. Although I know it is MUCH better. But to get 18mpg with a lifted jeep,...seems questionable. Did they have winches and bumpers like we do?

Have to remember, but keep in mind what I said before. All the mods I have made (except the re-gearing) has made NO change in the mpg.

I started recording mpg with a lifted and larger tires, on an other wise stock Jeep. MPG increased with the re-gearing and has been flat line since. That means all the sensors, the front bumper, KC lights, then winch, the custom rear bumper, rear spare, etc... etc... etc... NO CHANGE in MPG. :out:

[TeXJ]

Have to remember, but keep in mind what I said before. All the mods I have made (except the re-gearing) has made NO change in the mpg.

I started recording mpg with a lifted and larger tires, on an other wise stock Jeep. MPG increased with the re-gearing and has been flat line since. That means all the sensors, the front bumper, KC lights, then winch, the custom rear bumper, rear spare, etc... etc... etc... NO CHANGE in MPG. :out:

haha, you could get rid of your clutch fan