T43 - PCA Pressure - How to log / calculate?

[PHLTHS]

Hi Guys,

I'm in the middle of working on tuning my GM 6 Speed Transmission.

I'm looking at TCC Desired Pressure [TCM 5672 Table]. Whlist the Line Pressure channel (ParameterID="4212) is able to be logged, I wanted to ask if anyone knows how log or calculate the PCA pressure?

Chris @ HPT does mention the following: "There is an option to cal the pressure tables as line pressure or as PCA pressures. ie. you can cal the tables to already take into account the characteristic offset & gain of the setup. This gain is 2.045 which explains why the pressures in the tables are double what you are seeing in the scanner. The TCM divides the pressures by the gain value to get PCA pressure, which is what is displayed in the scanner."

I'm assuming here when he says "TCM divides the pressures by the gain value to get PCA pressure" He means ParameterID="4212" = PCS 1 (Line Pressure), however I cannot see the offset being factored in anywhere? Am I missing something?

I can see there are channels for the following:
ParameterID="4212" = PCS 1 (Line Pressure)
ParameterID="4213" = PCS 2
ParameterID="4214" = PCS 3
ParameterID="4215" = PCS 4
ParameterID="4216" = PCS 5

I have read the following threads, but none have difnitave answer to how to work out the PCA Pressure?
https://forum.hptuners.com/showthrea...RCLE-D-3000-HP
https://forum.hptuners.com/showthrea...eter-questions

Thank you.

[PHLTHS]

Thanks to Corey @ HPT for helping with this one.

We can now log the PCA Pressure <ParameterID>7165 in the latest version of the scanner as the engineers have added it.

This should help with working on the TCC Desired Pressure [TCM 5672 Table]

Cheers.

[hjtrbo]

Next time you're out and about would you mind sharing a datalog with the new channel working? Presuming you'd already have the PCS1-5 & TCC Pressure also logging...

[Jiggity 84]

Which version of the scanner allows logging?

[Cringer]

How do you get this to work? I downloaded the latest beta suite. And PCA did not show in the supported parameters (I did a re-poll). So I manually edited my channels.xml file like this...

<channel ParameterID="7165" />

Then the PCA PID shows in the scanner, but it is grey out and when I start scanning it disappears. Any advice?

[PHLTHS]

Just working on this guys with HPT. When I originally tested it, it was an exact trace of the TCC Pressure PID.

I reported this info back and they tried to fix it, but now it logs nothing. Provided the debug file and I'm waiting on their reply.


Thanks.

[hjtrbo]

There is only the 6 pcs solenoids that we already log. Of you want to calc line pressure I have a thread on it with the formula. Lines up pretty close with the shift tables.

[Cringer]

There is only the 6 pcs solenoids that we already log. Of you want to calc line pressure I have a thread on it with the formula. Lines up pretty close with the shift tables.

Link to formula?

[hjtrbo]

Calculated Line Pressure ≅ PCS1 x 2.045 + 300
Calculated Line Pressure ≅ PCS1 x 2.335 + 300

Somewhere in between is where it will likely be.