ok I might actually take my truck to the track on april 17th for that diesel day at lebanon valley. This will be the first time ive been to the track in almost 4 years, I want to get some times with my twins so I can say they are "proven" and maybe start selling some kits.
ive been working constantly on tuning and I am making some progress finally.
Ive narrowed it down to either a MAF or TCM issue. Im leaning more towards MAF.
Im basically starting over from scratch. I flashed a completely stock tune into my ECM. When I say completely stock, I mean completely stock. All DTC's enabled, etc. I full flashed it with a Tech 2 using the latest ECM update from GM, to rule out the problem being with efilive or the way its flashing my ECM. (flashed it the exact same way the dealer would)
As some of you may know there are two different calibrations from GM. One for the stock airbox, and one for stock trucks that have the LBZ-style airbox retrofitted. At one point GM's overheating "fix" was to install an LBZ airbox, and this of course needed a new MAF calibration to work properly.
So I started with a "cylindrical airbox" stock LLY calibration. Within 1 minute of just idling after reflashing it, it threw a P0101 MAF code. Hmmm interesting... So I cleared it and went out and drove it. Seemed fine, but after driving it for a little while and doing a couple WOT runs, the 4-5 shift started to get funky, like it started getting this big defuel (like the LBZ 1-2 shift defuel). Then I would try again and it would be fine.
Then I went to get on the highway and right after the 4-5 shift (with the big defuel), it did those surge/huge defuel things that it used to do.
SO. TO EVERYONE THINKING I SUCK AT EFILIVE, IT WASNT MY TUNE!!!! Because it clearly does the random surge/defuel events with a 100% stock tune.
:
And it is random, sometimes I would floor it on the highway and it would do a 5-4 kickdown and accelerate normally, then Id do it 2 minutes later, it could kick down, rev up, and right around 3100rpm it would start defueling. ITS NOT A MECHANCIAL problem or fuel delivery problem because I can clearly see the requested torque value jumping all over the place, from the normal (stock) ~550-590ft lbs WOT values down to 330, 280, etc... And of course the mm3 (main rate) follows that torque value which results in the surging/loss of power.
I still need to flash the TCM back to "real stock" with the tech 2 to try that and see if there is any change.
If there is no change then I will flash the ECM to "real stock" (tech 2) with that normal airbox (non-LBZ retrofit) stock calibration and see what that does.
Im not sure what others have found, but IMO the LLY really seems to depend a lot more on the MAF than we think...I might look for a new one/good used one and throw it on there to see what happens..
ben
ive been working constantly on tuning and I am making some progress finally.
Ive narrowed it down to either a MAF or TCM issue. Im leaning more towards MAF.
Im basically starting over from scratch. I flashed a completely stock tune into my ECM. When I say completely stock, I mean completely stock. All DTC's enabled, etc. I full flashed it with a Tech 2 using the latest ECM update from GM, to rule out the problem being with efilive or the way its flashing my ECM. (flashed it the exact same way the dealer would)
As some of you may know there are two different calibrations from GM. One for the stock airbox, and one for stock trucks that have the LBZ-style airbox retrofitted. At one point GM's overheating "fix" was to install an LBZ airbox, and this of course needed a new MAF calibration to work properly.
So I started with a "cylindrical airbox" stock LLY calibration. Within 1 minute of just idling after reflashing it, it threw a P0101 MAF code. Hmmm interesting... So I cleared it and went out and drove it. Seemed fine, but after driving it for a little while and doing a couple WOT runs, the 4-5 shift started to get funky, like it started getting this big defuel (like the LBZ 1-2 shift defuel). Then I would try again and it would be fine.
Then I went to get on the highway and right after the 4-5 shift (with the big defuel), it did those surge/huge defuel things that it used to do.
SO. TO EVERYONE THINKING I SUCK AT EFILIVE, IT WASNT MY TUNE!!!! Because it clearly does the random surge/defuel events with a 100% stock tune.
:And it is random, sometimes I would floor it on the highway and it would do a 5-4 kickdown and accelerate normally, then Id do it 2 minutes later, it could kick down, rev up, and right around 3100rpm it would start defueling. ITS NOT A MECHANCIAL problem or fuel delivery problem because I can clearly see the requested torque value jumping all over the place, from the normal (stock) ~550-590ft lbs WOT values down to 330, 280, etc... And of course the mm3 (main rate) follows that torque value which results in the surging/loss of power.
I still need to flash the TCM back to "real stock" with the tech 2 to try that and see if there is any change.
If there is no change then I will flash the ECM to "real stock" (tech 2) with that normal airbox (non-LBZ retrofit) stock calibration and see what that does.
Im not sure what others have found, but IMO the LLY really seems to depend a lot more on the MAF than we think...I might look for a new one/good used one and throw it on there to see what happens..
ben
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