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The mkiv Supra Owners Club

gearbox diagnostics


adi

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Which terminals do you lot short out to find the gearbox diagnostics? I've tried E1 and Tt as described in the mk3 TSRM, but it doesnt work. The gearbox and engine are more mkiv than mk3 so im going to try the mkiv connections, but i dont know which ones they are?

 

cheers

adi

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The symptoms are going to sound a bit daft..

 

Basically, when in a powerbrake situation ( foot on brake, and raise the revs), i know that the engine and gearbox would eventually overcome the brakes and makes the rear wheels break traction and start to spin, or at least twitch, at about 1800 or more revs. Even the TSRM for the mk3 states that at 1800 revs with both the footbrake and even the handbrake fully engaged that the power still eventually get through and cause the rears to start spinning.

 

Mine dont.. even at 2400 revs and with my foot planted back hard.. the engine just struggles against the gearbox and the rears sit there motionless, even with light half pressure braking. I can just about make them spin in the wet but its difficult.

 

I also get appalling takeoffs, up to three seconds to hit 30 mph. Also, as far as im aware, with a stall rate of 2400 (as my box has) that on a normal takeoff the engine should 'slip' up to the stall point on a spirited drive away.

If i plant my foot back in a normal takeoff the revs dont slip at all, yet rise steadily with the movement of the car..slowly until hit 300 when it flies.

 

 

Someone has suggested i may have a 'broken one way clutch (sprag) in the stator of the torque converter' or poor line pressure, either by solenoid trouble or something else.

Unfortunately my gearbox is *impossible* to find info on (A342E).. and i do mean impossible... very very impossible... hence i cant find out whether this is a feature of the gearbox , or a fault.

 

Turbo lag has been suggested, but it was doing this when i had my stock turbos, and they produced virtually no lag (almost full boost avalable at 2000 rpm).

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Yeah right !!!

 

:)

 

So do you have any diagnostic trouble codes stored? i.e. is the engine check light on or does the OD light flash or something?

 

 

I would have thought that Toyota would follow the same method of DTC retrieval as for all other Toyotas.

 

Do you have the MkIII engine manual that descries the DTC procedure?

 

Pete

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Honest ! the 1JZ has full boost very very low down the rev range.. almost instant ! the stock turbos are tiny and very light just for that purpose :)

 

No error codes but after repeated faults the ECU stops giving them (as noticed with my boost cut)... so i could still have them stored... battery gone flat now anyway so id need to drive it again to make some appear.

 

The general mk3 stuff doesnt apply to the 1JZ mk3.. its more mk4 than mk3, same for the gearbox.

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