$42 TH400 settings question

[blue68deville]

What do the TH400 settings do in $42? Are these hi/lo enable speeds for kickdown? What does the TPS setting do?

[mmigacz]

Somebody can confirm this, but I don't think the ECM can communicate with the TH400. There are no triggers or sensors built into the TH400.

[blue68deville]

The ECM grounds the kickdown relay to energize the solenoid in the valve body. I'm wondering if these settings are for that ground signal.

[dave w]

The ECM grounds the kickdown relay to energize the solenoid in the valve body. I'm wondering if these settings are for that ground signal.


I think you are using an older .xdf file, V4 maybe? The most current .xdf can be downloaded here: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?304-1227747-ECM-Information-42 I think the parameters you have posted are not listed the same in the latest version $42 .xdf file.

The 1227747 will operate a TH400 relay with a ground signal for the "Kick Down" or "3rd gear down shift into 2nd gear".

dave w

[blue68deville]

These are what I'm using, per EagleMark's links;

$42-1227747-V4T.xdf and $42-1227747-V3T.adx are advanced files with Data Tracing for TunerPro V5 RT. For Turbo 400 (http://shop.ebay.com/i.html?_nkw=turbo+400) trans/3 speed bin files.


If I use the V5's I get TCC lockup options only

[dave w]

These are what I'm using, per EagleMark's links;

$42-1227747-V4T.xdf and $42-1227747-V3T.adx are advanced files with Data Tracing for TunerPro V5 RT. For Turbo 400 (http://shop.ebay.com/i.html?_nkw=turbo+400) trans/3 speed bin files.


If I use the V5's I get TCC lockup options only

Ok, the above is correct.

The answer to your question, yes the ECM sends ground to the TH400 Kick Down Relay using Pin A7 of the 1227747 ECM. I have not figured out which parameters are involved in changing the TH400 Kick Down. Maybe the shift indicator inputs / outputs?

dave w

[blue68deville]

Ok,that's how I have it hooked up. I have the GM wiring manual for 89, it's been very helpful.
I may play with some of those settings and see what happens. Pretty sure I'm not getting electrical kickdown as is, or at least not where I'm expecting it. It only seems to 3-2 downshift in ranges where the modulator is doing it.

[dave w]

Ok,that's how I have it hooked up. I have the GM wiring manual for 89, it's been very helpful.
I may play with some of those settings and see what happens. Pretty sure I'm not getting electrical kickdown as is, or at least not where I'm expecting it. It only seems to 3-2 downshift in ranges where the modulator is doing it.

One option would be to use the old style TH400 kick down switch to apply ground to the relay. http://www.gearhead-efi.com/Fuel-Injection/showthread.php?610-1228747-Turbo-400-4F

As I understand it, the relay need to send 12 volt ignition power to the kick down switch in the transmission.

dave w

[blue68deville]

Oh I thought about doing the easy thing and just put the switch from the Q-jet back, but what fun would that be?
I'd really like to have the ECU do it. If needed I could try to read the stock bin and do some comparing.
I'll post whatever I do/don't figure out after this crap weather goes away and I can drive the car again.

[1project2many]

There are several settings the need to be adjusted to use a 7004R file with a THM400. TCC lockup tables are only part of the equation. Have you done a comparison between a 400 calibration and the one you're currently working with?

[dave w]

I did a compare between AMUC (TH400) vs. AMUR (TH700R4), which showed 869 bytes difference. There are several undefined bytes, which might be for the TH400?

dave w

[blue68deville]

Im using the ANTY bin from here, my ecu had that as the stock chip and would run/drive. I'm just looking to see if or how kickdown can be adjusted.
It is a TH400 bin.

[1project2many]

It can be adjusted. TCC operation is roughly inverted from kickdown. TCC is "on" at low throttle and load while THM400 is "on" at high throttle and load. Factory calibration values set downshift at or near WOT.

Simple test is to connect a test light to solenoid coil + and apply WOT while driving. Confirm proper electrical operation and TPS indicating 100% throttle before working to change calibration.