A34*E kickdown issue?

[Endless]

I have recently put a new 2nd hand auto box in my JZA70 and have had this weird issue happening since installing it.

When driving along around 60 - 80km/h and giving it some full throttle action the revs rise to 4k and seem to sit there for a second, then it will keep revving and be on boost straight away.

I'm wondering if this could perhaps be to do with the kickdown cable because i know they have some control over fluid flow / pressure in the valve body.

I have had a look and the cable seems to not be as tight as the throttle cable, but when i turn the throttle the kickdown cable will pull straight away it just seems like theres a bit less tension on it - not sure if this is to do with the problem or not..

Anyone have an idea on how you adjust the kickdown, or any other idea as to why it would be doing this?

[chris davey]

It isn't a kickdown as such but yes it does control line pressure. I have mine setup so that the throttle cable can fully extend and at that point the auto cable starts to get a bit tight. Just fiddle around with it for a bit to get it about right.

Why do you think it is the auto though? If it is hesitating, maybe fuel delivery isn't 100% (pump, filter, injectors, ecu or FPR) or the ignition is not 100%. (cracked coils, plugs old?)

[PT1]

does it misfire at all when it sits at 4000rpm?

really need a better description of what happens at that moment. Does it produce rpm but no acceleration etc?

[Endless]

There is no misfire and it has only done it since i've put this new box in.

It's like it just holds at 4k accelerating at a normal pace but without gaining revs for half a second then continues on happily.

Used to be fine with the old box it would just miss gears on the change which is why i put in another... that leads me to beleive it's not the fuel and moreso something to do with the box.

Also has brand new plugs and new coilpacks.

Might try have a play around with this kickdown adjustment, could you get a pic of yours for me Chris?

[jampac]

Sure it doesn't have a big stallie in it?

[Endless]

Hmm looked like a stock stall converter when it was put it in the car, my brothers JZZ30 has a 2500 stall and that is noticable when you drive like it wont roll forward in drive on flat ground and takes a few revs to get moving, my car still seems like it used to be taking off etc... though i haven't tried getting on the brake and launching yet.

[Endless]

Had a look at a mates kickdown and it was tight, i also found out my bolt was threaded all the way to the opposite end (rearward instead of forwards) might take her out for a spin tonight see if it's fixed.

An added Q - could too much fluid in the box cause these symptoms?

[2jzhilux]

there will be a little tag on the cable that should be adjusted so it sticks out the housing about 2mm

[Dieseltrain]

Arent factory Jzz30 stallies rated at 3,000rpm?

[chris davey]

no way! 2000rpm or thereabouts. Depends on what turbo setup as to what it will actually stall to. The flash test is the way to find out advertised stall. As braking power plays a part in what the "brake stall" will be.

drive along at about 15km/h and then boot it and watch what the rpm "flashes" to. This is what the advertised stall should equal.

[Dieseltrain]

Ahhh ok, shall do that when i go for a drive shortly

[1JZ.747]

adjusting the kick down cable changes the line pressure and harshness of the gear changes all one way and it will be a comfortable gear change, the other way, harsh.

i changed mine foem half way along to full forward and we increased the line pressure by 65 psi. and it gained another 3.4 mph

[Endless]

Well finally took the car for a test spin tonight, the issue still seems to be there and i'm starting to think it might just be something that i will have to live with having
auto + safc2 + big single.

Adjusting the kickdown did make the shifts an insane amount harder at all speeds, doesn't just do a little chirp now does a decent one and tries to kick sideways a bit... Awesome!

I'm wondering what else i could try...

Something i thought of was the fact i put some BKR7E's in not long ago, but the car was tuned with the safc with BKR6E's - not sure if that could relate to the problem i'm having though, might try put some in on the weekend to rule that out.

Not sure what else i could try otherwise... fuel filter?

Any other suggestions / thoughts?

[rob_85]

manual ?

[Endless]

I knew at least one person was going to say that!

I'm saving don't worry... but for now would just like a solution.