A heads up for y'all.

[swathdiver]

Yep, i would pop the mass air flow out once a year and give it a shot of electronic cleaner. Such a random post, but I had two high mileage 6 speeds come in this week with the same issue. Obviously won't fix all of them, but something to keep in mind.

Every January here, which reminds me, one day left to do it! LOL

 

[OR VietVet]

I would assume the quality of the air filter makes a time frame difference as well.

 

[hagar]

when I cleaned my maf, I could see in the logs that I was in a different part of the Dynamic airflow vs rpm map under the same condition. in my case I was logging timing. it moved me higher in the map where it actually ran less timing for the same "load". dynamic airflow bring a blend of maf and map values. they say about 95% of it is map, especially steady state throttle.

I could definitely see the tcm using lower dynamic airflow numbers than it should messing with tranny shift times and pressures.

It's true. If you for example went into your maf transfer function and added 20 percent to the calibration, thus telling the engine it is getting more air flow, your truck would run higher in the load and timing tables. If you pulled fuel out of the maf calibration, the truck would run more ignition timing and show lower in the load based tables such as shift pressures and oncoming clutch volumes and such. It's why so many people used to/still do, wreck the 6/8/10 speeds, they don't calibrate the engine computer to report the correct torque value to the tranny control module. The days of a tranny using rpm and throttle position as it's way to control pressures are gone, it's all about making sure the trans knows what torque the engine is running at. That's why a dirty maf not showing the proper amount of air, makes the computer think it is running at lighter load, then it tells the tranny control module the engine is making less power, so it doesn't need as much line pressure and such.

 

[j91z28d1]

I would assume the quality of the air filter makes a time frame difference as well.

when I cleaned mine, it looked more like black oily stuff. like it came firm the pvc system or intake than anything that could come thru the air filter. but yeah, makes sense if you say over oil a k&n style.

 

[Marky Dissod]

It's true. If you for example went into your maf transfer function and added 20 percent to the calibration, thus telling the engine it is getting more air flow, your truck would run higher in the load and timing tables.
If you pulled fuel out of the maf calibration, the truck would run more ignition timing and show lower in the load based tables such as shift pressures and oncoming clutch volumes and such.
It's why so many people used to/still do, wreck the 6/8/10 speeds, they don't calibrate the engine computer to report the correct torque value to the tranny control module.
The days of a tranny using rpm and throttle position as its way to control pressures are gone, it's all about making sure the trans knows what torque the engine is running at.
That's why a dirty maf not showing the proper amount of air, makes the computer think it is running at lighter load, then it tells the tranny control module the engine is making less power, so it doesn't need as much line pressure and such.

So, is it a good idea to try to 'trick' the ecm into thinking its load is slightly higher than actual?

 

[OR VietVet]

when I cleaned mine, it looked more like black oily stuff. like it came firm the pvc system or intake than anything that could come thru the air filter. but yeah, makes sense if you say over oil a k&n style.

I really do not see the draw of the K&N filter.

 

[hagar]

So, is it a good idea to try to 'trick' the ecm into thinking its load is slightly higher than actual?

I personally set the tranny tunes up so they don't go below a certain shift torque factor setting. There is a lot of room in the part throttle shifting range to make things more aggressive, without making the shifts annoying. The benefit is not only better shift feel, but tranny longevity by getting the trans in and out of gear quicker, and with less slip time.