Shifting harsh/soft with Speed Density (LS1 PCM)...?

[joecar]

Harsh Shifts:

Disable P0101, P0102, P0103 in the following tables:
- E0102 Transmission DTC Fault Max Pressure Enablers
- E0104 Transmission DTC Fault Pressure Modifiers

Also disable P0101, P0102, P0103 in this table:
- E0103 Transmission Failsafe Enablers

Also check this table for/disable P0101, P0102, P0103:
- E0101 Transmission DTC Fault Processing Enablers
(that table probably won't contain those 3, but check it anyway)


Soft Shifts:

When driving monitor/log DYNCYLAIR, TRQENG, TFMPRS...

The PCM computes DYNCYLAIR from the VE table for various purposes:
- to compute/lookup fueling/fuelmass,
- to compute/lookup spark timing,
- to compute/lookup TRQENG;

TRQENG is used to compute/lookup the PCS current (or duty cycle) to drive the PCS with... in the hydrualic schematics the PCS produces Torque Signal pressure which drives the Boost Valve which assists the Isolator spring in driving the Pressure Regulator valve to control line pressure.

So, if the VE table is low, then DYNCYLAIR will be low, which causes TRQENG to be low, which causes Torque Signal pressure to be low, which causes line pressure to be low, which causes slippage which kills the transmission and the fluid.

When you view a log of TRQENG and TFMPRS, look at the shift pressure tables in the transmission calibration and see which cells TRQENG is looking up... at WOT these should be saying 80+ psi for TFMPRS.

So if you're running/tuning in SD be careful that the VE table is not going low by mistake (it will make your transmission slip, and it will make your AFR lean which will increase CC temps, cause knock, damage motor).

[N0DIH]

Thanks! This is something someone else and I have talked about from time to time. People changing out MAF's have problems with transmission shifting.

I know on my L29 454 With TC2 I can disable some of that, but not all those switches in most cars/trucks have it defined.

I see the light! Thanks!!!

[hymey]

Joe, P0101-0103 are for MAF fail DTCs which tables do u mean?

Joel

[joecar]

Joe, P0101-0103 are for MAF fail DTCs which tables do u mean?

JoelJoel, I added the table ids to post #1.

[hymey]

Thanks Joe, Had this issue yesterday for a T42/A4 setup. The tables you list I couldn't find in this T42 computer. I am guessing they are LS1 related? This car had an e38 controlling the engine. Anyway thanks to Alian's help(much appreciated Ian) I was told the fix is in E1006 which is in the latest update.

For harsh shifting with e38 Speed density tune and T 42 combo....Select Stop Adaptive learn, Pressure Solenoid Default and Inhibit Torque Management all to NO so the whole E1006 table will all read NO. This is the fix for harsh shifting with T42 controlled A4s. This is the table here.....

[joecar]

Yes, at the moment I have only my LS1 to play with.

[Chevy366]

Thanks Joe, Had this issue yesterday for a T42/A4 setup. The tables you list I couldn't find in this T42 computer. I am guessing they are LS1 related? This car had an e38 controlling the engine. Anyway thanks to Alian's help(much appreciated Ian) I was told the fix is in E1006 which is in the latest update.

For harsh shifting with e38 Speed density tune and T 42 combo....Select Stop Adaptive learn, Pressure Solenoid Default and Inhibit Torque Management all to NO so the whole E1006 table will all read NO. This is the fix for harsh shifting with T42 controlled A4s. This is the table here.....

Thanks for that tidbit of info hymey .

[Chuck CoW]

Harsh Shifts:

Disable P0101, P0102, P0103 in the following tables:
- E0102 Transmission DTC Fault Max Pressure Enablers
- E0104 Transmission DTC Fault Pressure Modifiers

Also disable P0101, P0102, P0103 in this table:
- E0103 Transmission Failsafe Enablers

Also check this table for/disable P0101, P0102, P0103:
- E0101 Transmission DTC Fault Processing Enablers
(that table probably won't contain those 3, but check it anyway)


Soft Shifts:

When driving monitor/log DYNCYLAIR, TRQENG, TFMPRS...

The PCM computes DYNCYLAIR from the VE table for various purposes:
- to compute/lookup fueling/fuelmass,
- to compute/lookup spark timing,
- to compute/lookup TRQENG;

TRQENG is used to compute/lookup the PCS current (or duty cycle) to drive the PCS with... in the hydrualic schematics the PCS produces Torque Signal pressure which drives the Boost Valve which assists the Isolator spring in driving the Pressure Regulator valve to control line pressure.

So, if the VE table is low, then DYNCYLAIR will be low, which causes TRQENG to be low, which causes Torque Signal pressure to be low, which causes line pressure to be low, which causes slippage which kills the transmission and the fluid.

When you view a log of TRQENG and TFMPRS, look at the shift pressure tables in the transmission calibration and see which cells TRQENG is looking up... at WOT these should be saying 80+ psi for TFMPRS.

So if you're running/tuning in SD be careful that the VE table is not going low by mistake (it will make your transmission slip, and it will make your AFR lean which will increase CC temps, cause knock, damage motor).


Thanks Joe! Very good information. Seems to work very much like the new A6 does.

The real fix for LS1s with A4 transmissions and nice power is to install the TRANSGO Vac Mod kit which replaces the PCS with a new valve and an old school modulator. No more computer.

This is a MUST for boosted vehicles cause the torque rise of a boosted engine does not match the line rise programmed into the pcm.

When using the modulator kit, whenever there is no vac (ie. boost) you have max line....Very nice....

Chuck CoW

[hymey]

thanks for the info guys. I did another A4/LS1 today but this time the normal LS1 pcm. I tuned it mafless The shifts were pretty good. The ve table was spot on spent a bit of time on that including delibrately heatsoaking the intake to get the iat bias correct.

Modifying the box and using an old type modulator is interesting, I didnt know you could do that, is it possible to use an A4 with the above mod without any computer control behind an e38 equipped 6l?

[Chuck CoW]

thanks for the info guys. I did another A4/LS1 today but this time the normal LS1 pcm. I tuned it mafless The shifts were pretty good. The ve table was spot on spent a bit of time on that including delibrately heatsoaking the intake to get the iat bias correct.

Modifying the box and using an old type modulator is interesting, I didnt know you could do that, is it possible to use an A4 with the above mod without any computer control behind an e38 equipped 6l?

Nope....won't shift.

You'll need an old 700 R4 with hydraulic shift control...

Chuck CoW

[joecar]

Yes, the vacuum modulator should probably be renamed "MAP modulator"... it increases "throttle signal" pressure as vacuum goes down (i.e. as MAP goes up)... just like the THM400/THM350, and others like the Ford C4/C6/FMX...

[throttle signal pressure assists the pressure regulator in controlling line pressure]

Various vendors make vac mod conversion kits for the 4L60E/4L80E (like TransGo ans Sonnax).

While the vac mod controls line pressure mechanically (by manifold pressure), the shift solenoids in the 4L60E/4L80E still need to be electrically driven, so a controller is still needed; various vendors make standalone controllers (like TCI).