So I just picked up my tactrix cable and bought a copy of evoscan. So beware the newbie.

I'm getting
Fuel trim low = 100
Fuel trim mid = 130.46875
Fuel trim high = 150


And none of them change. During the course of a 15 minute drive, not a single different value.

What are these trims for? Why the low, mid and high?

Since they haven't changed, I'm assuming they aren't short term trims.
And I can't seem to find short terms in EvoScan.

I'm attempting to make some tuning changes for my test pipe and intake but am trying to understand what's going on first.

 

Also, your opinions on my logic of maf scaling would be helpful.

1. I have an intake.
2. I want to change maf scaling so that my short term trims are closer to zero
3. This ensures that I have compensated for differences in airflow due to the aftermarket intake.
4. Once this is done, I should work on modifying the fuel maps

Does anyone know what the stuff in the MAF scaling map mean?
Left column has values from 192-16384
Right column has values from 145-237

 

The high trim is actually low trim. The latest version of EvoScan has them messed up. All 3 are long term trims. The short term trim is O2 Feedback.

Regarding the MAF scaling, the actual function of those maps has not been documented as far as I've seen. I recommend leaving them alone until their effects have been documented a bit more. If you want to get your fuel trims close to 0 the only trusted and documented method thus far is by adjusting the fuel maps.

-Paul

 

Thanks for the info.

I'm looking at my 02 feedback trim and they range from 90 to 130.46875 (fuel trim mid)

Do you happen to know what these numbers correspond to in terms of trimming percentages?


As for the MAF scaling...I may mess around with it and see how it changes the short term trims. If no one knows what it does, someone has to experiment to find out right?

hehe...I just need to find out how I load a freakin map now
A little nervous about immobilizer codes and f*ing my ecu.
If I pull my stock map, modify it and send it back, I shouldn't have any sort of ecu locking/disabling issues right? I wrote down the immobilizer code anyway.

 

The o2 feedback value is equivalent to the short term fuel trims in a regular OBD-II logger... The other trims are long term trims, I never see high change, but low and medium are Idle/low rpm, and Cruise... I suspect High might have something to do with high load trims (A/C or whatnot) but I've never seen it change either..

Mitsulogger I chose to keep the trim conversions close to what an OBD-II would report, that is +/-25% max, 0 being perfect.. On Evoscan, I think 100 is the perfect trim.. Therefore if it reads under 100, it has to remove fuel because its rich, and if its over 100, it has to add fuel because its lean.. Hope that gives you some insight..

 

If your using your own map, the immobilizer code will go back in with your map.. Its good you have it backed up, along with your original map.. save that info somewhere along with your stock original map.

If you used a different map then you have to add your own Immobilizer code.

 

I think I get it a little bit better now.
I was wondering if the trims went negative in a typical OBDII scanner type format...

So 100 = zero in an OBDII world.

Can you provide any insight into why there are 3 long term trims or how MAF scaling actually works?

I'd like to scale first, before adjusting fuel maps.