Can you clear LTFTs before tuning VE?

[Supercharged111]

This has been bothering me, on an OBDI computer you can simply unplug the battery to reset everything on it. On my computer though, I have to wonder if I didn't tune my VE with pre-existing LTFTs in there? Do they stay in there with each update to my tune? How do you wipe them out?

[ScarabEpic22]

I dont know if you can do it on the Black Box PCM, but I know for LS1/E38/E67s you can use the Scan tool and DVT controls to reset the fuel trims. Try connecting to it as a LS1 PCM and see if you cant reset the trims that way.

[joecar]

Also, in the tunetool you can set the option to clear DTC's after a read/flash...

Edit->Properties->DTC

Like Erik said, the Black Box PCM may or may not support this.

[Supercharged111]

Oh rearry. Does clearing the DTCs also wipe out the fuel trims? Or was that just an additional helpful hint? This is just yet another reason to get off my arse and swap in the 411. . .

[Chevy366]

Doesn't "full flash" clear LTFTs ?
Try just doing a 'Full Flash" not "calibration only" flash should clear LTFT .

[Supercharged111]

What's the difference? I usually pull the tune, make my changes, and reflash. Is that enough to wipe out LTFTs? If so, I've got nothing to worry about. It's just that, IIRC, when I pull the tune it's 512k and when I flash it's only 96k.

[Chevy366]

What's the difference? I usually pull the tune, make my changes, and reflash. Is that enough to wipe out LTFTs? If so, I've got nothing to worry about. It's just that, IIRC, when I pull the tune it's 512k and when I flash it's only 96k.
Yeah that is calibrations only , why it is 96k and not 512k , full flash will be the full 512k file size .
The DVT control )most likely isn't supported by Black Box PCM) , or "full flash" 512k )don't know if that is supported as well) are the best bet to make sure they are reset .

[Supercharged111]

Blackbox = useless. :wallbash: It's unfortunate that a 4.10 swap and other goodies have stood in my way of 411 swapping in recent days. I still have the excel document from Lextech in my inbox. As soon as the wife leaves, the 411 is going in!

[ScarabEpic22]

For most GM PCMs, if they dont directly have DVT support try connecting to them as an LS1B PCM for earlier ones (Gen III PCMs) or E38/67 for later ones (Gen IV). Usually some of the DVTs work, CASE relearn and LFTF clear should work on almost all GM PCMs (including oddballs like the P06 V6 PCM that EFILive doesnt even support).

[EagleMark]

Blackbox = useless. :wallbash: It's unfortunate that a 4.10 swap and other goodies have stood in my way of 411 swapping in recent days. I still have the excel document from Lextech in my inbox. As soon as the wife leaves, the 411 is going in!It's not that they are useless, it's that the files have never been fully documented like the LS 411. Instead everyone keeps referring to a 411 PCM swap.

Other software has way more parameters to help with a tune and I'm sure theres more.

[EagleMark]

Also, in the tunetool you can set the option to clear DTC's after a read/flash...

Edit->Properties->DTC

Like Erik said, the Black Box PCM may or may not support this.


Oh rearry. Does clearing the DTCs also wipe out the fuel trims? Or was that just an additional helpful hint? This is just yet another reason to get off my arse and swap in the 411. . .


Doesn't "full flash" clear LTFTs ?
Try just doing a 'Full Flash" not "calibration only" flash should clear LTFT . The 98 Black Box PCM does support clear DTC upon flash.

Didn't see an answer here on how to clear LTFT or if clearing DTCs will accomplish this. Is disconnecting batterey the only way?

[Supercharged111]

I think the 411 is the only way. . .

[EagleMark]

DTC does not.

Tried the Calibration LTFT Learn in Scantool and grayed out.

Tried connecting as LS1 and LS1B to activate DVT and no go.

So how long does battery need to be disconneted? Only takes a few seconds on OBDI...