I have a 1993 Accord with a obd1 jdm h22 with the matching auto trans and jdm tcu (transmission control unit). I needed to pull off the positive wire on the battery to work on it and when I put it back on the car now shifts at 6,000 instead of 7,200. It has shifted at 7,200 ever since the swap was done and all of the sudden it changed to 6k after I took the power wire off for about 15 minutes. Has anyone else run into this issue before? Any help would be appreciated.

 

It sounds like the TCU is re-learning

I would give it a few days.

 

that's what happens when you pull the power. like aforementioned, it'll relearn your driving habits soon.

 

I have manually shifted it from first to second a few times at 7k and it still shifts at 6k if I let it shift for me. I drove around slow letting it shift at like 2,500 before but when I was at wide open throttle it allways shifted at 7,200. I don't think it "learns" other wise it wouldn't have allways shifted at 7,200 at wide open throttle no matter how I previosly drove it.

 

swap to a manual transmission and shift whenever the hell you want.

 

word

 

the auto tranny will shift depending on lots of variables. at wot it'll tend to shift a bit before redline because of the tq curve of the engine. give it time to relearn or manual swap ftw

 

Doed the JDM tranny have a throttle cable attached between the throttle body and the throttle valve B lever on the tranny? It sounds like it might be too loose. The adjustment point is on the tranny.

 

The cable is a good idea but I checked it today and it doesn't have any slack in the cable and the two locking nuts are still tight. I am guessing that my tcu has tacken a crap.

 

it actually sounds like your shifting correctly now. my car never went past 6500 before it shifted but i was using the f22 tcu as well. you reset the computer in which probably wasn't in the right mind state to begin with. the auto shifts before redline to save on the wear and tear that a 5 spd can handle unlike its counterpart. if your tcu scrapped on you, it would probably be worse than what it is.

 

Well if you have the true TCU(p19) which is rare but possible, it had a feature known as the "s" mode where the shift points change to make it more sportier and such. Its possible a switch needs to be hooked up to the TCU. Look into that if your stumped

 

It is a P19 and it did shift at 7,200 at wot on any gear and now it is at 6 in every gear so that sounds like something needs to be switched. I wonder how to "switch" it back? And for Flight50 the stock F22 tcu will make it shift at redline of the F22. If you switch the tcu to a p19 it will shift at 7,200 all day like mine used to (as long as your ecu is a P13 and has the auto matic wire connected to the proper terminal on the harness).

 

IMO i wouldnt be shifting that high because honda automatics are really really really poorly build. Ive only had my H22/auto for 10k miles and its already slipping really bad. 5 speed swap will smooth things up : )

But just so you can check, the pin D20 on the TCU is the S switch wire. Just FYI USDM preludes were not wired for the "s" switch so you can go buy a normal on/off switch at an autopart store to wire it in. If there is a wire on you D20, it should be red according to the JDM service manual

 

When I wire the switch what is the red wire? Is it a power wire (so the other wire on the switch needs to be a ground)?

 

its your car. your pushing your luck going that high with an automatic. unless your just trying to break it so you can do a 5 spd swap, i'd deal with the quicker shift points. and no, my car never dipped into the red valve when i pushed here using the f22 tcu. maybe my installer hooked it up right or they hooked it up wrong, but either way, until i swapped over to a 5 speed, my tranny held together. and i pushed it every chance i got. including chirping my tires for a second in first gear.

 

Correct.

 

I appreciate everyones help on this and I will wire up a switch this weekend and try it out.

 

bro,
does your rewiring work for your p19tcu? I also have a p19tcu/p13ecu but the car only shift at 6500.