i have read many many forums and posts and haven't been able to come to a solid conclusion on what years the t100 ecu works when mating a 3.4 to a 3.0 auto transmission. i know the 1998 t100 auto 4x4 ecu works but will other years? The part numbers are different from other years to 1998. i know the speed sensor is the issue with the 340h trans. looking for someone who knows first hand. like been there and done that. thanks guys

 

talked to one of the specialist today that does these swaps. he said any of the t100 auto ecu with the 3.4 will work with the 3.0 auto trans. he was confident. he did mention that the tps and maf sensor have to be from t100. i am going to have to research more on this. hope this helps

 

*In mid ’97 Toyota started using a 3-wire Throttle Position Sensor (TPS) instead of a 4 wire unit. Unfortunately the two have a different throttle body, so changing from one type to another requires changing the entire throttle body.

**’99 and later air flow meters are a “piggyback” style that mount to the side of the intake tube. ‘’98 and earlier air flow meters are larger and fit inline with the air intake tube. Both types have the same electrical connectors but will cause very poor driveability with the wrong ECU.

 

Um, I said that you were pretty dismissive of it... Glad you got a hold of a "specialist"

 

thanks for your reply. great info. i have done some more digging on my ecu question. i seems the newer 3.4 (mines a 2000) engine uses the 3 wire tps and you need the matching ecu to communicate with the tps. i think the only matching t100 3 wire tps ecu is the 1998 which will also communicate properly with the stock ( 3.0 enigne) 340h transmission. i still have yet to confirm this.

 

Keep in mind that the T100 was only produced through the 1998 model year.

Go to the junk yards or http://car-part.com/ and buy a T100 ECU (95-98, with more of a focus looking for the later years), then go through your engine (which you say is a 2000) and start swapping sensors/parts until the engine matches a 3.4 from a T100 of whatever model year your ECU is from.

Go ahead and just assume that you're going to have to buy a new MAF and throttle body, and if you can get away with re-wiring/swapping sensors, consider yourself lucky.

 

Also the older ECUs can simply be repinned to fit the newer "drop in style" MAF, so whichever you've got will work. See here: http://bb.bc4x4.com/showthread.php?1...r-build/page23

Dunno about the TPS thing. A throttle body swap is simple and just feed your ECU the info it seeks, just match functions.

 

thanks for the comments. I'm hoping to do enough research now to avoid swapping parts out like the intake for the tps. i think I'm on the right track. haven't found any write ups say other wise yet. I'm just going to buy wiring harness conversion for 700$. i would rather work a little over time and pay someone else to bang there head figuring that part out lol. i don't like the fact i still have to wire starter signal and 4-lo solenoid. but still working on the ecu

 

So am I correct in assuming that the t100 ecm will(can) be used with your late-model 3.4 harness? It seems to have been established that the t100 ecm has the correct functions for the a340h, but I'm not sure how people are running it with their existing wiring harnesses.

Is this a matter of grafting the 3.0 auto harness into the 3.4 harness and matching it up up the a340h sensors? Or is changing the harness out with a matching t100 unit necessary?