Can we control or test the line pressure or force motor current on an automatic?
if you get me the mode 4 commands and I'll happily add them to the beta, maybe kur4o has them
On another note, the filtered VSS was around 1/2 of my actual speed on the transmission tab.
can you give me a log with both the engine and transmission data together? i can correlate the two and figure a proper correction factor and fix the definition.
force motor dc m4 command
00 00 00 00 00 00 01 xx 00 00 00 00
xx=dc%
3-2 sol dc command
00 00 00 00 00 00 02 xx 00 00 00 00
xx=dc%
egr dc%
[ON] 00 00 00 00 00 00 04 xx 00 00 00 00
xx=dc%
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FORCE motor, 3-2 sol, and EGR are exclusive. Only one at a time.
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tcc pwm sol on/off
[Off-0% - byte 6, bit $02 must be zero]00 00 00 00 02 00 00 00 00 00 00 00
[ON-100%]00 00 00 00 02 02 00 00 00 00 00 00
extend IAC to max position
40 00 00 00 00 00 00 00 00 00 00 00
alright, the next version will have that fixed, and i'll work on adding the transmission stuff.
what's a good way to express line pressure? 0-255? 0-100%? or is there some unit conversion into psi i can do
force motor is line pressure control, right?
Last edited by steveo; 06-21-2016 at 05:06 PM.
can anyone think of a real reason i should add 32DSS or EGR duty cycle (for tuning, not just as a toy)?
i've uploaded a new beta this morning with line pressure control from 0-255 for testing, should be online shortly
I've seen GM documents for testing line pressure that say to use the TECH and change the current in 0.1A steps. So, it'd be interesting to see if this is current or % duty cycle. If it's current then there should be some conversion possible between the raw 0-255 into 0-1A. If it's % duty cycle then the range can only go to 100%.
There is no conversion for pressure. The internal setup in the transmission can change how much pressure a certain force motor current produces.
The AT pressure control is very convoluted. The tables and factors all use 0-96 "pressure" factors which are looked up in another table to convert to current. The PCM sends the current to the transmission which hopefully is working correctly and produces the correct pressure. The PCM only has feedback or monitoring for the current, not the line pressure.
Are you talking about being able to control the EGR solenoid manually??? If so, I would be super excited about that. I've been doing my research and I think there is more MPG to be gained from the EGR tuning, but I can't get the ECM to control the solenoid like I want it. A manual control would be huge for me.
alright i'll roll it inAre you talking about being able to control the EGR solenoid manually??? If so, I would be super excited about that. I've been doing my research and I think there is more MPG to be gained from the EGR tuning, but I can't get the ECM to control the solenoid like I want it. A manual control would be huge for me.
I tried to sniff GM OEM tool, mode4 for line pressure, but it did Park/ Neutral check first.
At my test bench I couldn`t lie PCM, it`s in P/N, so I couldn`t see how it controls the pressure.
For safety reason you can add that check before Line pressure control is enabled.
I am not sure what will happen with transmission if you play with line pressure at gear or car is moving.
So put some big warning on it.
Also during the sniff I made, the OEM tool sends f4 56 08 command before any f4 56 01 mode request and some times add f4 57 07 09 [which I have no idea why]
Maybe it can add to more stable connection at b/d body setup.
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