tried to tune on speed density

I tried tuning my l83 truck today with speed density and failed horribly at it and gave up. Here is the issue I was having. Anytime I let off the throttle the wb would read super lean and no longer register a air/fuel reading and it would skew all my numbers to lean in the 75-100% lean!

I thought by disabling DFCO that it was supposed to eliminate super lean readings when letting off the throttle?

It doesn't appear that DFCO was disabled though because it would go super lean after letting off the throttle and stop registering a reading on the WB and once i gave it gas the reading would come back to around .950-.980 lambda. Is this another gen V issue where you can't disable DFCO in the tune just like STFT's you can't either?

I heard there is a way to make a parameter where I can ignore any data when I let off the throttle? Can anyone explain it to me?

Use the insert variable function in the graphs layout for fuel trims and use [Accelerator Pedal PID] > 0

Basically that says only show me data where the gas pedal is greater than 0%

The final statement will look something like this: [12345.123] > 0

Quote:

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Originally Posted by TriPinTaZ

Use the insert variable function in the graphs layout for fuel trims and use [Accelerator Pedal PID] > 0

Basically that says only show me data where the gas pedal is greater than 0%

The final statement will look something like this: [12345.123] > 0

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Thanks so much! I'll give it a shot in tomorrow!

Man thanks TriPinTaZ that will help me so much!!!

I clearly did something in the math wrong. I set it up like my other Speed density graph but with the new math. And it will only log across the top line.

Attachment 101473

Quote:

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Originally Posted by Jonblarc7

I clearly did something in the math wrong. I set it up like my other Speed density graph but with the new math. And it will only log across the top line.

Attachment 101473

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So you don't want to edit your math. Go to graphs layout and then your speed density graph and under filtering that's where you would put the new filter.

I understand now thanks so much