VE Assistance/Verification

Hey everybody! Working on my first tune. 2004 Suburban, 5.3/4l60e. I installed a BTR Truck Norris Cam. Everything else is stock, but I have a small stall converter still to throw in. Also, when the machine shop went thru the heads, they had to bore out the seats and fit bigger intake valves, so its got 2 inch intake valves instead of the 1.87.

Anyways, I have a wideband setup and I've been following chopper doc's ls1 videos for setting up tables and making it idle and such. I'm wondering though, at a certain point do you stop copying/multiplying the whole VE table by 1% or .5%, and just do the cells that are overly rich? I'm nervous that if I continue to just do "paste special" on the whole table, it'll push me into the lean range in several cells.

Also, being that its my first time I'd love it if anyone could check out my settings and such and confirm that I'm doing this right. I have it in speed density for all the tuning so far.

Thanks!

I am relatively new to tuning as well, i started the same way you did applying the wideband calculated lambda error to my VE table, also with a BTR truck norris cam. I was then corrected to re-enable the pcm fuel trims, long and short, leave the maf failed for now, let the fuel trims make the corrections, and then apply them to the VE table, and use the wideband for PE tuning only.

Put it back into closed loop and adjust the VE with fuel trims. If the trims are off by 5-6 or more then multiply by full. Once you get it tighter, then multiply by half. Use plenty of filters on your data also. There is a bunch of threads about filters for the scanner.

Don't use filters for CL. Tune it like it's going to run. Let the fuel trims do their thing. There's a lot more going on than just error between commanded and actual.

Filter out decel and quick transitions. You can always remove filters after you have a base to see what the ECM thinks it wants.

It automatically "filters" decel and quick transitions. That's what it's doing while you drive. Understand what I mean? OL use filters yeah. CL don't.

I guess it's been awhile since I've done a gen 3 on the street. Sounds good.

You already understood it implicitly.

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Originally Posted by ns158sl

You can always remove filters after you have a base to see what the ECM thinks it wants.

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If what you're filtering is going to be different than what the ECU thinks then why filter at all? You aren't filtering for the ECU when it's going down the road. All you're filtering is the data received from the fuel trims, not the fuel trims themselves.

So if you run with an airflow model based on filtered data then you're baking in error that will always be corrected by the ECU. If you want to tune for accurate fuel then you don't want that error.

It's also the reason I insist on LTFT's.

On this issue I don't care who it is, how long they've been at it, or how many times it's been posted on this forum. Logic.

If the Cal is way out of whack, usually trims are way too slow to react and throw you off. Yeah you can literally comb through the log by hand but for someone new that is going to copy and paste, I'd say leave the irregularities out especially VE. Either way.

I'd put it back in closed loop and start logging.

Oh I see what you're saying. You're talking about making it easier to tell where to make corrections. Sure, whatever works for you is what works for you :) Personally, I prefer the raw data then visualizing the trends on the tables. Pretty easy to see where it's heading and which points don't fit.