1jzvvti>mx83 no overdrive after conversion. IDEAS?

[scrote]

Hey all.

Conversion was done years ago but never had the overdrive working.

1jz vvti in the mx83 cressida.

Was wondering if anyone else had an issue or if any ideas as to what area to look at first.

Thanks.

[70XIN]

This might be absolutely no help, but i was reading something today during my boredom about 4th/overdrive not working on MX83's if you have the ABS computer plugged in.. or something to that effect.

[NME308]

Hi there,
I know MX whatevers and JZ thingys like - um - absolutely not!

I once upon a time however had a VL commonwhore with nissan 6 plus auto slushbox. The proper little pig used to lose overdrive occasionally, and one cool willowbank morning it just wasn't there at all! I pulled the overdrive button out and checked it all operated and the signal was getting back to the ect/box etc etc. After quite some research it turned out among other things overdrive will not engage below a certain coolant temp - and some previous owner had removed the thermostat...


Anyhow my point is something along the lines of - is there anything specified in owners manuals from the doner vehicle or possibly something seemingly innocent which has been left out of circuit from the donor vehicle?

Cheers,
Jason

[triptek]

I'v seen 2 other 1jz vvti conversions with this exact problem. I'm also trying to figure it out. Recently i spent a fair bit of time with a complete jzx100 to trace the wiring. As far as i can understand the D wire from the auto selector on the side of the gearbox goes to the shifter in the car. From there it drives the 3rd and D lights on the dash. The D light also traces out of the dash down to the multiplex body ecu. I'm still researching it, but it could be a problem trying to get it to work.

[thechuckster]

ECU-driven toyota autos will not lockup until engine is at operating temps and speed over a set amount.

[madmont]

ECU-driven toyota autos will not lockup until engine is at operating temps and speed over a set amount.

My 2JZ mx83 would not change into overdrive until you had travelled about a kilometre
VVTIs are a bit different, have more computers, more headaches, Check your wiring diagram .I would consider a switch to bypass the computer and turn off the solenoids but then you have the lockup to consider. Does your lockup work?

[George]

Mine is a 1JZ VVTi converted car. Has no computers except ECU. Switches into o/d with no issues. I suggest doing the following:
1 check electric part. You need o/d switch and "o/d off" confirming light. With these two left unconnected, o/d is on by default. Check the polarity for both. If the o/d light flashes, read 2-digit warning light errors.

2 some kinds of trans fluid may result in loss of o/d. Dirty trans fluid filter and rather dead pump may be the reason as well.

[mx83turbo]

I've got a 1J vvti in an mx83, had same issue initially. There are two solenoids (S1 and S2) which control which gear (1-2-3-D) the box is in depending on which solenoids are on or off. There are two other solenoids in the vvti gearbox, one controls shift intensity and the other controls lock up. The shift intensity one is driven by a proportional voltage (0-6V while driving) depending on how hard you are going. The lockup solenoid as chuckster said requires a speed signal separate to the gearbox speed signal, my understanding is its taken off the front wheel in the chaser, and it might go through the abs computer on the way to the ecu i'm not sure.

My interim solution was to wire the lockup solenoid (SLU+ black/yellow, SLU- green/red) throught the un-used overdrive switch on the auto shifter, I added a fuel pump resistor in series to drop the voltage a bit as suggested by the toyota service manual when testing solenoids. Its been in and working for 30,000 km no worries. It was meant to be a temporary thing while I shopped for the front wheel speed sensor but i just got use to locking it once in top gear and unlocking it before it shifts down. It's not ideal but may provide an interim solution and save you some fuel til you figure out a perfect solution.

[Nilezy]

Do you have the TRC computer installed and working with your conversion?

I don't and have never had the O/D work, with the famous o/d light flashing.
I presumed that it was because of the missing TRC comp

[mx83turbo]

What are you guys calling overdrive? Isn't the 1J vvti auto just 1-2-3-D and then lockup? My car shifts through 4 gears, then when I manually lock it I get approx 2500rpm at 100km/h. Unlocked on level road I get about 2800rpm at 100km/h. Mathematically the D gear is an overdrive gear i.e tailshaft rpm > crankshaft rpm. Someone with an auto Chaser should be able to give an approx cross check for highway rpm, anyone?

[George]

Nilezy ,
o/d works with my conversion. Have just the main ECU.
mx83turbo
with A340E it means final (4th) gear, no matter if the converter is locked or not.

[Nilezy]

George,

We have the turbo VVTi motor, not the non-turbo motor.

You don't have Traction control on your motor and ECU is different to the turbo motor.

[George]

sorry,
in a month or two I'll install a turbo engine (1jzgte from jzs171) to mate's car, if I get the o/d working I'll let know

[CatzoFai]

ask Trip teck he knows or call tripteck in Perth Western Australia