Hi, so I finally got my Z on the road after far too long. I've never driven an automatic before so maybe it's just the way they are but it seems incredibly stupid to me.

It seems intent on revving the engine up for no reason, it holds onto low gears for what seems like an eternity before shifting up, and it will downshift if you so much as breath on the accel pedal. Even if you just increase the throttle just enough to maintain speed up a hill it will drop down and rev pointlessly all the way until the top. Accelerating at a medium sort of pace seems a chore too, really slow or fast is fine but 'normal' speed seems to result in this no mans land of torque converter slip.

 

Does this sound like normal behaviour of the autobox or is mine knackered and needing replacement? FWIW the TPS is calibrated perfectly so no issue there.

 

Cheers :)

Thats not normal boxes are slow in changing up but not like you described

Erm. Clarkey, have you got a Japanese autobox with the Power/Hold switch?

Certainly what you describe does not sound normal at all.

TPS settings are vital for the correct autobox gear change, a good test is if 1st to 2nd gear is to long a change but backing off the trottle makes its change up then TSP is the culprit, seen too many boxes written off as bad when simple adjustment is the issue.

 

Jeff TT

Can't you do an ECU check on the box ?

Erm. Clarkey, have you got a Japanese autobox with the Power/Hold switch?

Certainly what you describe does not sound normal at all.

 

Yes it's a JDM model, putting it in hold doesn't seem to make a great deal of difference.

 

TPS settings are vital for the correct autobox gear change, a good test is if 1st to 2nd gear is to long a change but backing off the trottle makes its change up then TSP is the culprit, seen too many boxes written off as bad when simple adjustment is the issue.

 

Jeff TT

 

Hi, yes 1st to 2nd does take too long and the change is often quite harsh. I used my datascan and the TPS is saying 0.42v at idle with the idle position switch working fine. This would be considered a good setting right?

clarkey , im local if you want to compare with my 300 then drop me a line

Yes it's a JDM model, putting it in hold doesn't seem to make a great deal of difference.

 

 

 

Hi, yes 1st to 2nd does take too long and the change is often quite harsh. I used my datascan and the TPS is saying 0.42v at idle with the idle position switch working fine. This would be considered a good setting right?

 

 

Yes thats ok for the tps, another check worth doing is the built in diagnostic see if any codes come up, also there is a drop resister that regulates the voltage to the 2nd gear solenoid and when that failes is makes the change harsher, its located up high in the passenger front wheel arch.

 

Jeff TT

Yes it's a JDM model, putting it in hold doesn't seem to make a great deal of difference.

 

OK. I just thought maybe if you'd not used an auto before you might have been driving around stuck in hold or 2 or something. It seems not. I've driven a few autos of various makes plus neither of my 300ZXs autos behave(d) as oddly as you describe.

 

Autobox diags and listen to Uncle Jeff - good luck.

Thanks for the advice guys :)

 

To make it clear what is going on I took a short video, keeping a constant throttle position the whole way, you can see how long it takes to shift up through the gears.

Thanks for the advice guys :)

 

To make it clear what is going on I took a short video, keeping a constant throttle position the whole way, you can see how long it takes to shift up through the gears.

 

Does not seem that bad, looks like overdrive might not be working though? cannnot be certain, some zeds need to be doing more than 60mph before it works some lower, depends on what speedo convertor is fitted, might be worth disconnecting the speedo convertor go back to KPH and see if your happier with it then, but as I said not too bad in the vid.

 

 

Jeff TT

there's no converter fitted, is a resistor modded speedo. It's wildly inaccurate too but I don't think it's related.

Check the kickdown cable is set correctly, it maybe to tight.

 

Paul