Hey guys just getting ready to start this LS swap and wanted to know if there is anything i need to do to this ecm harness since ill be using th th400 any help or links to help would be appreciated thanks in advance!

 

You'll have to figure out how to get an electric signal from the TH400 to the PCM to drive your speedo

The older trans requires no specific wiring to the PCM. Your shifter will already have a P/Neutral switch, so thats handled

 

Now im using mostly mechanical gauges so i really dont need to concern myself with the speedo right? Sorry i forgot to mention i previously had a gen I sbc in this car with the th400.

 

The PCM still needs an electric speed signal

 

http://m.summitracing.com/parts/atm-5291

does anyone know if this will work? Sorry to ask so many questions. I just dont know if the pcm requires a certain pulse rate?

 

Only for serial data communication or transmission control. He is using neither.

 

I just tuned the PCM for Manual so it didnt use any trans tables etc. Mine was a Manual valve body also. Much easier then trying to adapt a TV cable

Jay

 

It's also used when coming to a stop. Lots and lots of people have stalling issues when not using it

 

This th400 is a reverse manual valve body with a brake so should i send this ecm out to get tuned for that? And if i were to do that should i still hook up the speed sensor then? Whats your opinion on the stalling jay rich?

Thanks guys i appreciate all the info!

 

That is not because of a missing VSS signal. The stock automatic transmissions use a range sensor that allows the PCM to compensate for the additional load placed on the engine at idle in gear. Removing this only becomes a problem when large cams with lots of overlap are used with converters that are too tight. To avoid this you can modify an existing range sensor or spec the right converter for your application.

 

I ran a 3600 Stall on my TH400 setup for my Boosted 370ci build with a 236/236 112.5lsa cam. Ran great no surge. My buddy also ran a TH400 with a 4000 stall on his 370 N/A setup at 13:1 with a MS3 and it ran great too. He tuned both cars. He is now using it on a Boosted setup with a smaller grind cam.

Both were just tuned as a 6 speed car. His was originally a T56 1999 SS. Got sick of pulling the trans monthly lol.

I should add they were both tuned SD, no maf's.


Jay

 

Awesome thats good to hear can you elaborate on the SD rather than MAF? Im not sure what that means i was assuming the MAF sensor way was the only way to go

 

MAF is simpler to tune and is really nice for part throttle. But my car was Boosted and shooting for 700whp so was useless to me. My friend was going boosted so just spent a year tuning Speed Density. Only downfall is if you drive in a lot of weather changes.

Mafs will max around 500whp iirc.

Jay