Long trim fuel trim for 8.1, 2002

[coopcolt]

I checked the ScanGauge for 02, VPW.
The long term fuel trims was not listed.
As I am having (maybe) a power problem
I would like to watch the trims on both banks.
Can anyone lead me to the instructions with
all the codes to install such?

Thanks in advance....coopcolt

[CJ7365]

Here you go, I believe i got these from Kevin, I did look on the scangauge web site and did not see them


Short Term Fuel Trim
TXD 686AF10106
RXF 044105060000
RXD 2808
MTH 00C80100FF9C
NAME SF1

Short Term Fuel Trim
TXD 686AF10108
RXF 044105080000
RXD 2808
MTH 00C80100FF9C
NAME SF2

Long Term Fuel Trim
TXD 686AF10107
RXF 044105070000
RXD 2808
MTH 00C80100FF9C
NAME LF1

Long Term Fuel Trim
TXD 686AF10109
RXF 044105090000
RXD 2808
MTH 00C80100FF9C
NAME LF2

[Ultra RV Products]

https://www.scangauge.com/support/x-...obdii/#ISO/VPW

[chris-rector]

Jalisco's specifically for the Workhorse or do you miss me search for GM since it has an 8.1 liter in it do they use GM computers control it

[coopcolt]

Thanks CJ, got them installed. NOt sure what they
are telling me. I am pulling hard on I-81 south of
Bristol, TN. to exit exit 150 in Roanoke, Va.
Anytime the MAF gets near 100, both LTF peg at 19.

STF, both dance from mostly neg. 5 to pos. 5 points.
And will sometime go to the lower teens.

I was disappointed that under WOT my mas MAF reading
was 175, but I will have to see what the reading is when I
am not towing the Wrangler 4 door.

Thank for the information, ALL.
Jon, thinking I need the ultra-tune, I will get in touch!
coopcolt.....

[Isaac-1]

How are your spark plug wires?

[coopcolt]

I changed the plugs and wires 16/17 yrs. ago because of
all the problems. DOnt remember what they are, best I
could find at the time ...name brand, costly and so forth.

Not a bad ideal to change them as i am sure they have
aged out. I will check out the latest and greatest.
Thanks.....ccoopcolt

[CJ7365]

This link explains fuel trim

https://www.autoserviceprofessional....for-you?Page=1

Because your LTFT is high, I would start by cleaning the MAF sensor



A dirty or faulty MAF sensor can also cause positive fuel trim numbers because it “under-reports” airflow, driving the base air/fuel calculation lean.

[coopcolt]

Cleaned the MAF, twice, which is 16/17 yrs. old also.
Purchased an Andy Granatelli, when I put in the K&N
filter, all those yrs. ago.

OK, new MAF, new wires. Just put in new plugs last yr.
just cause! Search for a Delphi, or quality MAF.

coopcolt............

[Arch Hoagland]

If you over oil the K&N it will goof up the MAF.

[vettenuts]

I may be wrong, but if you are pulling hills and have your foot in it pretty hard to get up a hill, doesn’t the ECM go to open loop and work off the fuel/timing tables? Not sure the fuel trims mean anything when that happens.

[coopcolt]

I never go to WOT up hills, I did a couple of time just
to see what I could get out of the MAF...175, sown hill.
ANd once to check that it would go to open loop.

I have the old MAF. that had maybe 2/3 thousand miles
when i went to new, all those yrs. ago. In the box!...coop

[speed racer]

Fuel trim is determined by mass air flow, intake air temperature, manifold absolute pressure, unburned oxygen and engine temperature. If any of these sensors are reading incorrectly the ideal fuel trim can not be achieved.