acdii

You need to calculate 3 or more tanks, average it out, then make the adjustment, if you do it tank by tank you wind up chasing it.

On mine I went 4 tanks, and found I am now upside down and report under actual by .3 to .4 per tank. I'm perfectly OK with that too.

noclutch

Ok this may have been covered in the last 28 pages, but has anyone determined if the LOM is more or less deceitful under towing load partial tanks, or closer to reality on straight commuting tanks?

ie to get a good % adjustment number should calculate on a straight use or mixed use tank(s)? Or is it actually proportionally inaccurate regardless of efficiency, if that makes sense?

Put another way, will is my LOM % inaccuracy factor likely to be the same over a tank of towing, as a tank of commuting, and highway??

I'm confusing myself LOL

Race Red Rob

It is inaccurate across the board.
Correct it and it should be accurate in any use, straight driving, towing, whatever.

JCH841

I used to teach Marine EFI; can't imagine this is all that different. The injectors are designed to deliver a measured amount of fuel for aa given pulsewidth, The ECM uses this know relationship to estimate the MPG. if you're towing etc. the ECM will increase the pulsewidth while your miles traveled would not be affected, so the display would show a lower number. BTW, the display is a running average, so occasional towing would lower it, but not to the extent of actual usage while towing. You would have to reset the MPG display when you hooked up the trailer to get that.

noclutch

Thats what I was wondering.

For example on my last tank I towed for 100 miles and commuted for 530 and used 33 gallons. Display for the tank said 21.7 mpg, hand calc 19.1, yielding factor of .880.

But will the factor based on that tank and subsequent reset yield accurate mpg on my next tank when only commuting??🤯

MNgopher

As Race Red Rob put it, it is across the board inaccurate - towing, commuting, whatever. Does not matter.

In my case, I have the long term fuel mileage hand calculated with Fuel records going back to buying the truck. I set the number based on getting the average to meet my hand calculated number, and left it at that. There is still variation from tank to tank (for a ton of reasons), but as a whole, my fuel mileage is now around a few percent on either side of what I hand calculate, where before it was usually always 7-10% optimistic.

Set it once based on a good set of representative driving and forget it.

Kingofwylietx

^^^ This. Set it so it is more accurate and forget it. It will be much more accurate than before the change.

68injunhed

Mine tracks within a couple tenths either way now, with varied driving. Set it and forget it, my correction was 961.

h2ouup2

Nice,

Thank you

acdii

Mine is now Pessimistic. It is about 4 tenths under actual. Not going to bother resetting, I kind of like having it a bit under.