Does a speed density tune need a COS?

[Supercharged111]

Do you have an automatic trans? Electronically controlled? Reason I ask is because pre-411 swap I ran a VE tuned blackbox. I don't recall if I ran the 411 MAFless but I don't see why I would have. I do recall that being MAFless caused the trans line pressures to max out. I'm not sure if a COS would fix this or not. With the Transgo in the 4L60 I ended up cracking the case where the servo sits. It wasn't until well after the 4L80 swap that I plugged it back in. I think I plugged it back in right after the 411 swap because it was shifting so harshly no matter what settings I changed. I went so far as to double the factory torque reduction on upshifts and it did nothing. So I plugged it in and forgot about it. The next day on my way home from work the truck was shifting much more smoothly so I went into the tune and altered shift times to my liking and the truck took to it. I'm glad I plugged it back in, sure would have sucked to frag another trans.

[LastCall]

That can happen running speed density. There is a note in the AutoVe tutorial. I've pasted it below, you may want to check it out.

Vehicles equipped with automatic transmissions should go to table {E0104} Transmission DTC Fault Pressure Modifiers and set P0101, P0102, and P0103 to NO to prevent the PCM from increasing shift pressures.

[joecar]

Yes, set those to No...

and make sure the VE table does NOT under-report airmass.

[zapp168]

Did not check those tables, but the car is running and shifting perfect, I actually lowered the voltage on the force motor to firm up the shift a little.

[rich24v]

MAF plumbing needs to be straight before/after the MAF.

+1 what LastCall said...

summarizing:
- MAF-less, the GM OS's run from LO spark table.
- MAF-less, the COS's run adaptive HO/LO spark

Does this also apply to MAF-less E38 ?

[joecar]

Does this also apply to MAF-less E38 ?

MAF-less E38 runs from LO table (i.e. in presence of MAF DTC).

~Moderator~

[zapp168]

Did not check those tables, but the car is running and shifting perfect, I actually lowered the voltage on the force motor to firm up the shift a little.

They were already set to "no"