Misfire table tuning?
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TECH Apprentice
Joined: Nov 2001
Posts: 376
Likes: 3
From: Gary, In
Misfire table tuning? Can someone tell me exactly how to modify my misfire tables? Ever since I built this motor the trans lockup has been acting strange at times and I just installed a SS4000 stall yesterday and on a highway drive it's gotten worse with the trans coming out of lockup periodically for a minute then locking up again for a while before doing it again. And when the car idles for a while it's also detecting misfires case the ses light flashes. And I've read that rasing/maxing the misfire table should help with that. Also, should code P0300 be disabled? Thanks
I can post my tune if anyone cares to see it and tell me if I do need to change something.
I can post my tune if anyone cares to see it and tell me if I do need to change something.
This is an overview based upon information I found on HPTuners in 2008 (link below) and a PM I received in 2015. I'm of the opinion that completely disabling (aka maxing out) the misfire detection is a knee jerk reaction but I've not dealt with engines that potentially needed those drastic changes. Before making any changes I'd first confirm there are not any mechanical conditions that would cause a misfire and your fueling error is within 5%.
https://forum.hptuners.com/showthrea...hlight=misfire
Create scanner graphs for these tables:
* Misfire Rev Mode (all versions)
* CylMode (all versions)
Add all of the *misfire* channels to your channel list
Drive around to populate the new misfire graphs you created
Compare the data in your new misfire graphs to the matching tables in your tune. For each cell that has a value in the log, if it's higher in the log than in the tune, then raise the corresponding cell in the tune by a % and taper the areas around those cells.
For example, if "Misfire Rev Mode - Med", cell 25 x 2000 is 450 in the tune, but is 563 in the log, then I increase that cell in the tune by the percentage. So I'd change the cell in the tune to 450*1.25 to add 25% (for example) then taper the surrounding cells around the modifications. Rinse and repeat for all logged cells.Drive it for awhile and see if the P0300 returns. If it returns, and you're confident it is not a mechanical problem, you can repeat the procedure. I use an Excel workbook to make the process easier.
If someone else has a better way, I'm open to new information.
https://forum.hptuners.com/showthrea...hlight=misfire
Create scanner graphs for these tables:
* Misfire Rev Mode (all versions)
* CylMode (all versions)
Add all of the *misfire* channels to your channel list
Drive around to populate the new misfire graphs you created
Compare the data in your new misfire graphs to the matching tables in your tune. For each cell that has a value in the log, if it's higher in the log than in the tune, then raise the corresponding cell in the tune by a % and taper the areas around those cells.
For example, if "Misfire Rev Mode - Med", cell 25 x 2000 is 450 in the tune, but is 563 in the log, then I increase that cell in the tune by the percentage. So I'd change the cell in the tune to 450*1.25 to add 25% (for example) then taper the surrounding cells around the modifications. Rinse and repeat for all logged cells.Drive it for awhile and see if the P0300 returns. If it returns, and you're confident it is not a mechanical problem, you can repeat the procedure. I use an Excel workbook to make the process easier.
If someone else has a better way, I'm open to new information.
