Auto Troubles :-(

bluesteel · Post by **bluesteel** » Mon Apr 19, 2010 2:30 pm

OK so heres the run down of the car

1985 Brumby
G1S1 Liberty EJ22 Motor and Matching ECU and Loom
2000 GTB Auto Box with matching TCU and Loom
4" lift and 30" tyres

i have only just put the auto in and struggling to get it going properly

currently it takes off in first, but as soon as you try to accelerate or go any faster than about 10kmh it changes up to 2nd and struggles

the tiptronic + and - dont seem to make any difference either

once your up and running, it will kick back a gear when you boot it (not back to 1st tho) and it also seems to want to change up a gear well before it needs to

if anyone has suggestions of anything i can test, or try, or any info on how the box works in general it would be much appreciated!

cheers
Johnny

vincentvega · Post by **vincentvega** » Mon Apr 19, 2010 2:50 pm

you have taken on quite a challenge there mate!

If you had stuck with an early auto (< 99) i could help you out greatly with this, but the later stuff is foreign to me.

I would be starting with the wiring diagram for the GTB auto. look at all the connections between the TCU and box and make sure they are all present. Then look at any interconnections between the TCU and the ECU.. thats where you are going to struggle.

What have you done for speedo inputs into the TCU? Does the GTB box have an electronic speedo drive for the dash?

bluesteel · Post by **bluesteel** » Mon Apr 19, 2010 3:09 pm

all the box > TCU wiring is untouched
i have connected up a few sensors and power and earths as well

there are 2 speed sensors inside the box and one on the TC turbine thingy
im assuming there is a fron and rear half of the box speed sensors to control the VTD Centre Diff

the wiring diagrams i have are pretty helpfull but theres 5 or 6 wires the go between the TCU and ECU and thats all i can find out abuot them...

i have not connected up any of the steering wheel shift buttons or any of the dash lights etc (i wouldnt have thought they would stop the box from working)

i can post up relevent diagrams if you want to have a look see

Post by **Alex** » Mon Apr 19, 2010 3:17 pm

just a long shot and probably off the mark, but maybe the TPS is being weird?

bluesteel · Post by **bluesteel** » Mon Apr 19, 2010 3:22 pm

i originally had it hooked up without the TPS, (while i was looking for the info of which wires do what) and it was doing the same thing.
only difference now is that when you put your foot down, it will kick it back a gear

vincentvega · Post by **vincentvega** » Mon Apr 19, 2010 4:11 pm

mate you need to find a service manual that shows what the wires between the TCU and ECU are.

Also what polarity is the throttle sensor in a 2000 GTB? My guess would be opposite to a Gen1... so you might need to invert the signal.

bluesteel · Post by **bluesteel** » Mon Apr 19, 2010 4:23 pm

so far ive found 3 manuals that have those wires on them. the auto trans section says it goes to the ECU and to refer to the ECU Section, and the ECU section says refer to Auto Trans section... grrr

i just found some troubleshooting things that work off the power light, so ill wire one of those in and see what i can find

I know what input the TPS needs for the TCU and wired it up to suit

also going to try my local subaru service place, and see if i can find a workshop manual for anything with a tiptronic auto

tex · Post by **tex** » Fri Apr 23, 2010 3:36 pm

Just a random suggestion but you wouldn't be stuck in a get home mode or any thing stupid would it?

bluesteel · Post by **bluesteel** » Fri Apr 23, 2010 4:07 pm

i reckon theres a very good chance of that!

i have found out which wire the engine speed signal goes to so im hoping that will be the last piece of the puzzle!!

cross your fingers....

bluesteel · Post by **bluesteel** » Fri Apr 23, 2010 5:10 pm

turns out that didnt help

... back to the drawing board....

Gannon · Post by **Gannon** » Fri Apr 23, 2010 5:29 pm

2 of the wires that run directly between the TCU and ECU are the "torque signal" which makes the ECU retard the ignition timing while its changing gear. It to reduce shift shock.

But i doubt thats your issue

Are you using the tiptronic shifter?

It has a microswitch to differentiate between normal and sportshift when you push the lever sideways into the sportshift position. This isnt stuck on is it?

vincentvega · Post by **vincentvega** » Fri Apr 23, 2010 8:20 pm

torque cut wont be causing this problem. my TCU is missing its torque cut signal and it shifts fine.

as I said earlier mate you need to tick off 1 by 1 every connection into the TCU until you come across the cause of this.

you never did really answer the question of TPS polarity. the ECU will require a 5-0v signal because thats the way Gen1 worked.

Gen 2 on have 0-5v tps signal so I assume your GTB TCU would be expecting this.

I would look at the TPS voltages at the TCU and ECU andcheck they are correct... if the GTB TCU does need the 0-5v signal you will need a circuit to invert it.

bluesteel · Post by **bluesteel** » Sat Apr 24, 2010 11:07 am

the tiptronic switches seem to work (checked with the multimeter) but dont seem to make a difference to how the box is shifting

i will check the TPS and find out which way round the signal needs to be for the TCU

cheers!