A340E transmission problem

[PlacentaJuan]

suprastick doenst work with 2j boxes, i would have to use a 1jz box with a mechanical kickdown cabal.


mos how do i go about unplugging the solenoids?

is there a single plug i can remove or do i need to remove some pins from the ecu?

[131OWN]

there is a plug ( recall it is round) on the passenger side of the transmission towards the rear just before the extension housing, there is about 5 wires that run into it, these are the ones for the solenoids, just disconnect. when you do this you will not have 2nd gear. Shift Pattern will be
1st gear shifter position will be 1st
2nd gear shifter position will be 3rd,
3rd gear shifter position will be overdrive
overdrive switch will not work.

[big_zop]

It would be good if the A340E had a sport mode that relyed on a +/- for up /down shifts as you would be able to relocate those switches to the steering wheel.

There is a night pager paddle shift kit for some Nissans, but i believe the cost comes from the interface and specific moulding for the paddles rather than the cost of the parts (wouldnt be too hard to rig up two switches to the steering wheel but i dont know if the A340E operates this way).

Nengun - has a price ($1-1.1k )
Night pager site - in Japanese

What kind of inputs does the gearbox need other than the mechanical shifter, as this would help in being able to hopefully re-create the shift points with something of your own.

[Mos]

mos how do i go about unplugging the solenoids?
is there a single plug i can remove or do i need to remove some pins from the ecu?

Yes, there is a large(ish) flat(ish) plug at the back of the box (just before the extension housing) on the passenger side.

What kind of inputs does the gearbox need other than the mechanical shifter, as this would help in being able to hopefully re-create the shift points with something of your own.

That's a whole thread in itself....

The early boxes had three solenoids, two for gear selection, and one for torque converter lockup - these are fairly easy to run as it's only power on or off.

Later boxes had additional solenoids to control things like line pressure, accumulator pressure, etc. These are PWM controlled and I have no idea how the ECU decides to do what with them but basically they are there to make the box smoother on shifts (on the IS200 you can't feel the shift points).

Early 1UZ boxes have the line pressure solenoid, but I've seen plenty of posts/etc suggesting that not connecting this works fine (as it bleeds pressure, hence leaving it uncontrolled means max line pressure).

2JZ boxes have quite a few (can't remember exactly how many) and the 5 speed off the VVTi 1UZ is even worse

To my knowledge there is no controller off the shelf that will control all the solenoids, however I did once see a "transmission management computer" that you could program to do whatever you wanted it to do - basically an aftermarket computer for your box, at a similar price to mid range aftermarket engine computers.. (ie not worth it).

Mos.

[PlacentaJuan]

there is a plug ( recall it is round) on the passenger side of the transmission towards the rear just before the extension housing, there is about 5 wires that run into it, these are the ones for the solenoids, just disconnect. when you do this you will not have 2nd gear. Shift Pattern will be
1st gear shifter position will be 1st
2nd gear shifter position will be 3rd,
3rd gear shifter position will be overdrive
overdrive switch will not work.

but without overdrive or 2nd gear i cant test to see if this fixes the problem, since the only time it happens with when i command O/D off, or drop into 2nd gear!

[Mos]

Okay, if all you're changing is from O/D or to 2nd then it's the solenoids controlling this.

You could wire up an LED or a light to S1 and S2 and see if the solenoid does what it's told, however I suspect that those particular solenoids will be doing exactly what they're supposed to, just that the box is not responding as quickly due to the temperature (I'm perplexed why your temps are not higher after climbing hills...).

The other solenoids are there to increase comfort during shift changes, and they are likely to be doing something while the S1/S2 solenoids are switching, so it's not unlikely that the clutches are not locking up properly when you're thrashing it.

I don't know if there will be a way of diagnosing this - ie scoping the solenoid signals probably won't help, because if the resulting hydraulic operation is different to that expected the ECU has very little way of knowing this.
You could maybe measure pressure on the clutch actuators, but they you don't have access to do that, and you don't know if it's pressure or if it's the friction material that isn't grabbing...

I have a feeling it's the comfort features that are creating the problem but I don't think there'd be an easy way of checking this. Installing a early valve body could be part of the way of doing this. I'm also wondering what disconnecting all the other solenoids would do ... (ie wouldn't decrease line pressure on shifts, etc).

Mos.

[cambelt]

Sometimes the solonoids become intermitant , Will work for 1 hour then play up for 2 gear changes then back to normal again . I had a A340 do this which took me months to diagnose as it didnt show through diagnostics.
S1 or S2 may be the cause.
Dave

[PlacentaJuan]

update:

i have found that for some reason this problem is associate with the manual selection of first gear.

i think if i use first gear out of a corner and floor it then manually change up to second, for about 15minutes (at least) the gearbox is hesitant to respond to my gear selection.

i have also tried using the kickdown switch to select first gear out of a corner (ie: flooring it) and this doesnt seem to affect the gearbox.

i woulddnt bet 100 percent on these trials since they were only done once or twice because there isnt really anywhere i can go to floor the car in first on the street(it wheelspins like crazy)

when i can find somewhere i can really give it a go and let everything cool down and do it again i will know better but im pretty sure im on the right track to finding out what makes this happen at least

[Z2TT]

A340E's are known to have solenoid problems, petergoudie on here had a problem where his solenoids had a bad solder joint. My problem was that the solenoid had a bad earth, which was fixed by scraping some of the black coating on the solenoid mounting plate and the mounting bolt.

[PlacentaJuan]

ok i have narrowed this down to a problem with the transmission working as an engine brake (coast brake?).

it has nothing dto do with putting power down in certain gears.

today i nailed it in second gear right up to redline (or thereabouts) and let it coast back down to a lower speed in the same gear.

after that, the hesistaion started straight away.

so im pretty sure the same thing is happening in first (ie; a big decceleration that the gearbox must ocpe with before i floor it again) because if i use wheel braking only into a corner then plant my foot so it goes into first, there is no problem with the gearbox.

the gearbox is only picking up this problem after heavy engine braking (coast brake as per the a340 manual i think). i will read the a340 manual more to try to understand, but i tinhk i may require a different manual (the a341e?) hopefully the part i am looking at (coast brake) is identical accross the range.

[PlacentaJuan]

so after erading manuals and talking to people this seems to be electrical rather than a mechanical problem.

i will try using the aristo ecu to see if this fixes it, hopefully its not going to be con of using a jza80 ecu, but id rather put up with this than the fake rev limited like the aristo computar.

pls keep giving me ideas if you have them

[ZZT231]

Get a SupraStick with the paddle shifters etc, and tune the shift points the way you like it

You could also get a PCS Transmission computer (as it's more customisable than a Suprastick from what I heard/read? It's very adjustable in shifts vs throttle postion and easier to use. Apparently with the PCS you can wire it up and have a Tiptronic feature.



I thought a JZS161 auto was a A343E (100% electronic) with 5 solenoids and electornically different with the A341E which has 3 solenoids (doesn't Accumulator and Line Pressure solenoids).

so after erading manuals and talking to people this seems to be electrical rather than a mechanical problem.

i will try using the aristo ecu to see if this fixes it, hopefully its not going to be con of using a jza80 ecu, but id rather put up with this than the fake rev limited like the aristo computar.

pls keep giving me ideas if you have them

If your using the ECU that is for the A343E with some of the solenoids not hooked up, it might not be getting the right sensor information/feed in the shift mapping and not shifting properly?

Another thing is that have you looked at the TPS? Is it being intercepted or the signal being messed up as I know the transmission computer (TCU) requires a feed from the TPS, engine load (map sensor?) and road speed to determine when the car should shift. So when the car is on a flat bit of road it's working within the TCU range but as soon as the road speed changes against the TPS (up the hill), it could cause the TCU to panic and not disengage the torque converter hence why the engine feels hesitant?

I hope you fix the issue.

Cheers.

[wilbo666]

ZZT231:
JZA80/JZS147 has:
S1: Shift solenoid
S2: Shift solenoid
SLU: Lockup
SLT: Line pressure
SLN: Accumulator back pressure

JZS161 has
S1: Shift solenoid
S2: Shift solenoid
S3: ??
S4: ??
SLU: Lockup
SLT: Line pressure
SLN: Accumulator back pressure

To my understanding...

Both have accumulator and line pressure tho

Also I'm not sure what S3 and S4 do in the JZS161 box to be honest

Cheers
Wilbo

[ZZT231]

ZZT231:
JZA80/JZS147 has:
S1: Shift solenoid
S2: Shift solenoid
SLU: Lockup
SLT: Line pressure
SLN: Accumulator back pressure

JZS161 has
S1: Shift solenoid
S2: Shift solenoid
S3: ??
S4: ??
SLU: Lockup
SLT: Line pressure
SLN: Accumulator back pressure

To my understanding...

Both have accumulator and line pressure tho

Also I'm not sure what S3 and S4 do in the JZS161 box to be honest

Cheers
Wilbo

The JZX90 (Touring) A341E has:
S1: Shift solenoid
S2: Shift solenoid
SLU: Lockup
Accumulator and Line pressure is done by the kick down cable (mechanical function).

PlacentaJuan - Have you ensured that the TPS is reading the proper values (not stuffed?)

Cheers.

[PlacentaJuan]

PlacentaJuan - Have you ensured that the TPS is reading the proper values (not stuffed?)

Cheers.

not with a multimeter but i am very familiar with how the car behaves if its not working (did a lot of playing around with voltages to fix the fake rev limit), and i know that if the TPS is not sending the full range (at least to about 90% of max voltage of 5v) the kickdown switch will be ignored, which it isnt.