Technorati Claim post...

Ignore me.

Technorati Profile

TH400 electronic kickdown

My TH400 uses a solenoid to kickdown instead of the linkage method. Since this is controlled by the ECM (instead of TCC control) it needed new settings. RBob quickly responded with the following config which is working great. Posted here just to keep my notes together.
=========================================
What is interesting is that GM sets up the TH400 kick down calibration to use a set TPS%. Not based on MPH or RPM, just set to 85% in the case of ABHC. The thresholds are set up as the coast or decel TPS% unlock. Unlock (no kickdown) when the TPS% is less then the coast value. Then lock (do kickdown) when the TPS% is above the coast value.
So with that, this is what I found works for the TH400 kickdown (all TCC parameters). This is only bench tested, but looks OK:
Set Lock enable CTS to -40C
Set TPS% opening/closing deltas for unlock to 100% Set Relock delays to 0 (all) Set Forced Lock to 255 MPH
Set the 4 TCC TPS% unlock/lock tables to 255:
LoGr TPS% to Stay Unlocked
LoGr TPS% to Unlock
HiGr TPS% to Stay Unlocked
HiGr TPS% to Unlock
Set the 4 MPH thresholds to 0:
LoGr MPH OK to Lock
LoGr MPH to Unlock
HiGr MPH OK to Lock
HiGr MPH to Unlock
Set these 2 coast values to 85%:
LoGr Max TPS% coast unlock
HiGr Max TPS% coast unlock
Set these 2 coast values lower for hysterisis (probably mispelled), at 75%:
LoGr Min TPS% coast unlock
HiGr Min TPS% coast unlock
With these settings the TCC ECM output will go low when the TPS% is greater then 85%. The Relay is set up to provide +12 volts to the downshift solenoid whenever the TCC ECM output goes low (grounded).
RBob.

EPROM Emulator -- Ostrich

Since I've got the EBL, and a notebook pc to use with it, it became way too inconvenient to go to a desktop pc for editing of eproms. The Ostrich EPROM emulator by Craig Moates solves all of that. It replaces the EPROM and is fully programmable via USB port. Now I can monitor with the EBL interface and immediately update the tables in the controller. To top off the deal, Moates offers a discount towards the purchase of TunerPro editing software. I had been using "promedit" software to edit bins, but it had a limitation on the number of items it would recognize from a single .ecu config file. TunerPro doesn't have the same limitation and offers other advantages too. Very nice.

Engine hardware update

Been a while...cracked head interrupted EBL tuning. Those swirl port heads may have done something to create swirl (or maybe not) but they're weak castings. After 2 (!) cracked heads I've replaced them with aftermarket Dart Iron Eagle castings.

331ci Engine specs:
TBI unit (stock 1989 Suburban 2500 4x4)
trans-dapt TBI to 4bbl intake adapter
GM 4bbl intake
Hyd cam (.443I/E lift and 214d dur @.050)
Dart Iron Eagle heads (straight plug, 180cc I, 64cc chambers)
Speed-Pro Hypereutectic pistons (2 valve relief flat top - 327 + .030 over)
Stage II rods from Competition Products
350ci 2 bolt block
327 crank
OEM exhaust manifolds
Gutted cat
Dynoflow 3" turbo muffler