deceleration data in wideband vs narrowband tuning

Always had this question on my mind but never thought of asking until now where I really need to have a correct answer and stop the guess work.

I always filtered wideband AFR error readings vs MAF frequency on deceleration by forcing it to read above a certain TPS %, however I never did the same for the narrowband readings vs MAF frequency.

thanks in advance

i filter the maf using map, about 5 kpa above idle

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Originally Posted by carlrx7

i filter the maf using map, about 5 kpa above idle

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that doesnt sound like the best method because you have much more vacuum at cruise than you do at idle, gets more obvious with bigger cams, so you will be missing out on quite some data in cruise.

I do it by TPS %, if its idling at 20% I filter out anything below say 22% that seems to be working nicely.

But again, whats the purpose behind filtering deceleration data on cars that do NOT go into deceleration fuel cut-off?

Here is an example of a log I just did, if you goto frame 28185 and onwards you can see that according to the wideband the AFR is richening up for quite a bit after a WOT pull even though the PCM is commanding stoich. Might this have something to do with why my truck gets 8 miles to the gallon? :banghead: Truck is a TVS2300 427 ls7.

Filter out short term fuel trims of zero (you actually have to do less than 0.1 and greater than -0.1). This filters out power enrichment too.

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Originally Posted by DSteck

Filter out short term fuel trims of zero (you actually have to do less than 0.1 and greater than -0.1). This filters out power enrichment too.

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Example of the filter equation if you please? Need a 'not equal to' statement.

Can you define two filters in the same Histo?

I don't remember offhand what the identifier is for STFT. It might be 121.

[SENS.121] > -0.1 and [SENS.121] < 0.1

Thanks, I'll look up the PID later tonight. Much appreciated.:cheers: