Fuel trims whacked at WOT

[99Silver5.3]

Ok, tuning guys. Im no expert here but im stuck. I keep reading of the 5 and -5 rule for the LTFT's. But at WOT my LT's shoot to a positive 22. Which to my knowledge is indicative of a lean condition or the PCM trying to compensate 22% fuel. What do I need to do or look at to get the trims to zero like they should be? Or is it a better idea to skip watching the trims and pay attention to my wideband??

[vv8]

did you plug the hole going to the t/b? I told you they were going to be all feckup lol.

[99Silver5.3]

<div class='quotetop'>QUOTE(vv8 &#064; Mar 19 2006, 09&#58;13 AM) [snapback]47384[/snapback]</div>

did you plug the hole going to the t/b? I told you they were going to be all feckup lol.
[/b]

They were all fucked up before that man. After this breather deal, they are still the same.

[FlaBouy]

At wide open throttle you should not see LTFT&#39;s or STFT&#39;s. They should quit reading around 4000 rpm or about 65% Throttle. That is where PE takes over. Your LTFT&#39;s and STFT&#39;s should go to zero across the board when PE takes over.

[chrisj6]

not true, you can see LTFT at WOT. STFTs are shut off at WOT, but only positive Ltrims show. I would see what your wideband shows, thats going to give you the real story.

Chris

[FlaBouy]

<div class='quotetop'>QUOTE(chrisj6 &#064; Mar 19 2006, 08&#58;17 PM) [snapback]47429[/snapback]</div>

not true, you can see LTFT at WOT. STFTs are shut off at WOT, but only positive Ltrims show. I would see what your wideband shows, thats going to give you the real story.

Chris
[/b]

H-m-m-m-m Every time I go WOT my LTFT&#39;s and STFT&#39;s go zero across the board and my histograms show zeros in both tables. That one of the indicators I used to watch the spray on my meth. I guess you are telling me my LTFT&#39;s are probably negative? If so I just learned something. Guess I can call it a day.....

[chrisj6]

Yeah I have had many scans show +1 and +2 on WOT, your trims are either negative or dead on 0, which is a good bet if you have a Nelson tune, I never saw many +trims on mine&#33; Now me trying to tune on my own on the other hand, I&#39;ve seen my share of positive trims&#33; The pcm adds the positive trims just for a safety measure.

Chris

[Gordy M]

I always thought the STFT went to zero above 4000 rpms and the LTFT held steady. LTFT are only updated every 10 minutes from the STFT&#33;&#33;&#33;&#33;

[chrisj6]

ohhh LTFT are updated much more frequently than 10 mins&#33; Have you set your histogram to last value lately and watched how frequently they change?

Chris

[Zick]

<div class='quotetop'>QUOTE(99Silver5.3 &#064; Mar 19 2006, 01&#58;34 AM) [snapback]47375[/snapback]</div>

Ok, tuning guys. Im no expert here but im stuck. I keep reading of the 5 and -5 rule for the LTFT&#39;s. But at WOT my LT&#39;s shoot to a positive 22. Which to my knowledge is indicative of a lean condition or the PCM trying to compensate 22% fuel. What do I need to do or look at to get the trims to zero like they should be? Or is it a better idea to skip watching the trims and pay attention to my wideband??
[/b]

What is your WB reading?
I had a similar problem where I was reading very positive LTFTs all of a sudden. It turned out to be my scanner config file was corrupt. I created a new one and viola, it was working normal again.

Edit; Opps just noticed this is like 2 months old. lol