1jz manual conversion...auto computer?

[chicane ma71jz]

hi all,

just about to put a new manual box behind a 1jz in my 89 ma71...just wondering if i can still get the auto computer to run ok with the manual? am i able to just cut the wires running to the auto box? i would hazard a guess that i could, as they shouldnt affect anything with how the engine runs...but im not sure.

as engine management goes, im probably going to upgrade to a power fc sometime soon, which should run auto or manual fine, so should i just wait til i get that ecu before putting the box in? if i can get the new box to run with the standard ecu, so it can be manual for a while before the new computer, then that would be good, but if its going to cause problems i will just wait.

any info would be much appreciated

cheers guys

[SLO-055]

with some auto to manual conversions i've done, you'll find you do need those wires, as when you flatten the throttle, and take off up the road, your ecu sees massive load, revs, but no speed as the speed sensor (which is one of the wires to the auto) isn't hooked up, and pretty soon it'll stop the fun, leaving you with an annoying cut out, much like a boost cut. whether this is the case or not for your setup i'm not sure, but i'm pretty sure you'd be better off to grab a manual computer, or figure out some way of 'sensor bending' that sensor (tricking the computer into seeing there is some load, enough to stop the 'cut').
aside form that, i'm not sure that you can get a power fc plug in for an auto 1j computer, but i'm not that well versed in what the power fc caters for.
happy trails.
ed

[FASTFOO]

Do it the computer will not care.
I Have done about 5 of these with no probs.
the auto computer runns a manual!!!!

MATT.
EX-Toyospares

[acmtt]

I can see no reason to cut the auto wires.

leave them unplugged. You will need to short the nuetral start switch. Reverse lights and speed sensor/ cable will need to be plugged in.
The wires going to activate the solenoids are fine to just zip tie them up out of the way and the car will work fine.

[JetspeedCamry]

^ As suggested, leave the loom unplugged. No reason to cut it.
All i did was connect wires from that loom so a plug for the reverse lights, and bridged the neutral start switch. The rest works fine. Wether its 100% or not is yet to be figured out on mine, seeming it has these "odd problems" like a surge and some jerkyness when on and off the throttle, but otherwise, runs fine. PowerFC will clean it all up nicely though, so in the meantime just do it and enjoy!

[SLO-055]

i'll just shut myself up then!!!
jus seen some where auto has speed sensor, manual doesn't.
here obviously isn't the case.

[JetspeedCamry]

i'll just shut myself up then!!!
jus seen some where auto has speed sensor, manual doesn't.
here obviously isn't the case.

I would imagine that would be the case with newer types of ECU's and what not. Since the multitude of sensors and inputs that the ECU uses is grown alot since 1990! But on OBDI cars like this, the main ECU doesn't rely on the transmission computer as much (or at all).

[Endless]

As said you will need to short the neutral start switch to get it to start, but apart from that shouldn't be a problem running on the auto ECU.

As for Power FC's - you will not find one for the JZA70 that runs the auto i can tell you that 100%.

AFAIK the ONLY Power FC that runs an auto box is for JZX100.

[chicane ma71jz]

ok well im guessing, from whats been said, that by just unplugging the wiring from the auto box, and bypass the inhibitor switch, the auto ecu should run manual fine? im not too concerned about things like reverse lights at the moment, that can be sorted out in future, i just want to get the box/computer combination working ok first. but from what you guys have told me it should be alright.

thanks a lot for your help

[JP]

it will work fine.

I used an R154 in my chaser with an auto JZX81 ECU.

I went to the extent of removing all the auto solenoid wires etc from the engine loom to clean it up, I just bridged the neutral start switch.

You can grab the reverse light switch wires from one of the auto plugs down the side of the box, the wiring diagrams for those plugs are over at that 1jzgte-us site, can't remember the exact address.

The main speed sensor input to the ECU comes from the dash cluster, I'm not sure if your running an electronically or cable driven speedo cluster. If it's cable-driven, you can screw the speedo cable into the sender on the side of the R154 box. If it's electronically driven, you can screw on the electronic sender from the original auto to the side of the R154, that's what I did with my chaser.

You will get a flashing O/D light on the dash as the ECU will complain about the missing auto solenoids, just remove the bulb from the cluster.