5.3 with TH400 harness questions.

[Playtoy_18]

Been building a harness for a 5.3 in a 1969 chevy shortwide the past few nights.
About to pin the connectors and have a few questions.

Owner is using a TH400 and will not be using a VSS. I've explained the issues with not using one and he'll add one later maybe but not now.

I figured I would simply program as a manual (I warned him of possible idle issues with this).
while repinning however I came across the CPP and got to thinking.

If it's programmed as a manual,it would not be able to control TCC lockup right?

The harness is hasn't been totally wrapped yet,so if I need to add something now is the time.

How has everyone else dealt with convertor lockup,programming,pinning etc.. for a TH400?
I know nothing of the TH400 at all,I have changed a few camaro's over to manual after they swapped but it was a quick program and never heard from again as I remember.

[Six_Shooter]

Unless it's a later TH400 with a lock up ther's notjing to worry about. If it is a later TH400 (TH400C if I'm not mistaken), then you will need to either add a VSS or go with a vacuum set-up to control the lock up.

i wouldn't do the conversion without a VSS, I wouldn't have given that option.

[EagleMark]

After I proved the internet wrong about running without VSS... I'd never do it again, not even on the old 7747 which is the easiest. Which usually get used in Off Roaders and rock crawler so no E trans or even TCC, but it does help stable idle which is something really needed it the off road case.. Just to many quirks and dual tables ETC... to tune out. ARG!

There is still the kick down which is electric off throttle usually at gas pedal. Dave W is the one to talk to about that. It does look for VSS or? For certain speed before it can be active? Not sure how to on newer OBDII stuff but here's some info on what he did with 16197427 PCM.

http://www.gearhead-efi.com/Fuel-Inj...With-Turbo-400

[Six_Shooter]

Mark just brought up a good point, what ECM are you using? You may HAVE to use a VSS so that the proper tables are being used while driving down the road.

[dave w]

I think one option to eliminate the VSS ('0411 PCM) would be to raise the Abuse Mode Enable RPM's to maximum, or ZERO out the Abuse Mode Disable Speed. Might be a good idea to raise the p/n rev limiter to maximum.

I'm confused about the TH400 having a lockup torque converter. I can't remember a make / model / year that the TH400 had a lockup torque converter. I've been thinking the TH400 needs a kick down / passing gear switch to change gears from 3rd gear to 2nd gear.

http://www.gearhead-efi.com/Fuel-Inj...ections!/page4 post 56 I shows how I installed an accelerator mounted kick down switch on an '8747 ECM to '7427 PCM upgrade.

Maybe I got this all wrong about a TH400 not having a lockup torque converter and needing a kick down switch??

dave w

[Six_Shooter]

Sorry, It just came to me, it was a TH350C, that had a lock up converter.

I might have been thinking of a switch pitch converter that I believe was available in the TH400.