LTFT WOT check

[dsmlights]

hey guys is this how u guys check that your ltft are accurate. I went into the logger and found this.

[eboggs_jkvl]

I believe the LTFT on WOT don't exist. At WOT, you read your A/F as the O2s are not being used to set LTFT.

Not the crack tuner here, but I read a lot.

Elmer

[dsmlights]

no i am refering to how people say that the LTFR will carry over to WOT if Positive, how do they determine that, by using this screen.
Or just by logging?

[eboggs_jkvl]

Do you mean add or subtract fuel at WOT from the last reading of the LTFT at WOT?

If you are rich and the PCM is subtracting fuel to maintain 14.7 and showing a negative number in LTFT then at WOT you use the PE table as shown.

If you are lean and the PCM is adding fuel to maintain 14.7 and showing a positive number in LTFT then at WOT the PCM adds fuel to the mix and makes life miserable when trying to tune WOT settings.

All I do is log and insure that the LTFTs are running negative. That way the A/F is adjustable from the PE table. The only other "cough" is COT. If COT is set a little higher, then it won't splash fuel into the mix and the A/F at WOT can be controlled entirely by the PE table.


Elmer

[dsmlights]

Do you mean add or subtract fuel at WOT from the last reading of the LTFT at WOT?

If you are rich and the PCM is subtracting fuel to maintain 14.7 and showing a negative number in LTFT then at WOT you use the PE table as shown.

If you are lean and the PCM is adding fuel to maintain 14.7 and showing a positive number in LTFT then at WOT the PCM adds fuel to the mix and makes life miserable when trying to tune WOT settings.

All I do is log and insure that the LTFTs are running negative. That way the A/F is adjustable from the PE table. The only other "cough" is COT. If COT is set a little higher, then it won't splash fuel into the mix and the A/F at WOT can be controlled entirely by the PE table.


Elmer
where can I find more info on COT

[eboggs_jkvl]

Well, are you running with CATs? If no, then you just crank up the COT numbers and it goes away. If you are running CATs, then you need to raise the number but not go nuts. I don't have CATS so it doesn't matter. One of the more avid tuners might give you a suggested number for Catalytic Over Temperature settings that will still offer "some" protection to the CATs but will hold the settings higher than stock to stop the "splash" of fuel to "protect" lean CATs.


Elmer

[joecar]

The AutoVE tutorial shows how to prevent COT influence on actual AFR.