Hi guy's

Can somebody please tell me if when you floor the car in first from standstill, the car hits the rev-limiter before changing into second or is there something wrong with my Autobox.

Cheers Dave.

err, not sure, but pretty sure that should be the case in power mode, and if u floor it it foes into power mode so yeah i guess its ok, u will prolly get a fair bit of wheelspin doing that tho

Mine does and its a jap import incidentally. I was wondering the same thing but i guess its right??!!

 

Latz

Sounds about right to me. It may well depend upon whether the autobox has been upgraded.

Mine has never hit the limiter in any mode. The only time I can do that is if I've limited the gear change using the shifter. Doesnt sound right - unless its been modded in some way. Mine always changes at 7k clockwork.

But 7k is the (standard) rev limiter.

Dave - does your car hit the limiter, nosedive, you lift off, then it changes up? Or do you just keep your foot planted, watch the RPM bounce off the limiter and then have it change up?

 

Can you run an Auto transmission diagnostic?

Az

 

[edited cos a) I can't read, and b) I couldn't even spell the *wrong* name right..]

 

[This message has been edited by aaronjb (edited 27-11-2001).]

Have you had the speedo changed to show mph? or just had a sticker over the dial instead? Wondering if it could be interfering with the ECU signal?

What Aaron is describing happened to my old Honda legend, just used to bounce off the limiter, lift off and it would change up. I used this as bargining power when I bought the car. Sure enought 2 days later, oops no gears, only reverse.

 

I'm not saying this is the same in this case but just my experience.

 

Tim

The reason I described it, is it's what my car used to do.. I thought the gearbox was fritzed..

 

Turned out to the the speedo covertor, if I ran an auto diagnostic, the gearbox was recording a speed sensor fault.. Removed the speed convertor (back to kph) and everything was hunky dory..

Dave,

 

An appology is in order I guess, having reread my posting I didn't mean to put the S**ts up you, my posting was really about my previous auto box experiences, not even with a Nissan

 

Tim

Lol Tim.. Stop trying to scare the poor bloke

Hi Guy's

Thanks for the replies.

Right then i have just had my autobox Recoditioned, 12 months guarantee etc.

Now i know my car didn't do this before.

So i took it back and they are trying to tell me that's what they are all like!!!!.

Here is what it actually does.

Sitting at the lights, floor it to pull off and it revs right round to the red-line, but then hits the rev-limiter, the car bounces off the rev-limiter for a couple of seconds and then changes into second.

Now that doesn't sound right to me.

Once i know for sure that it isn't supposed to be like that, i can take it back and get them to fix it!!!

I'm sure that before it hit the redline only and changed, not the rev-limiter!!!.

What do you reckon guy's.

Cheers Dave.

You're dead right that isn't right there should be a smooth change at the readline upto 2nd, there is no way it should bounce off the redline for a couple of seconds.

 

The Nissan autobox is just about the smoothest I've driven, yours just doesn't sound right.

 

I'm not an auto expert, it may be just an adjustment thats needed, I had a recon box fitted in my Honda and that too had a problem at the end of the 12 months.

 

My advise take it back to the reconditioners and get them to fix it.

 

Where are you? I'll gladly bring along my auto for them to compare, if you're not too far away, I'm in Kent so everyones a long way away, or I'm sure there are Z owners near you with autos.

 

Tim

Now that doesn't sound quite right to me. Did you have the line pressure upgraded (for a faster change) or was it just the straight rebuild.

 

Yes, reckon you should take it back ...

Do you have a stock ECU? As the JWT increases the redline by 500rpm.

 

I'm sure that won't help but there you go!

 

Simon

Think you'll find it's only by 200rpm actually - up to 7200rpm.

I'm sure mine hits the limiter for about a second as well, but I usually back off a bit so it changes up. I wish I had the car now so I could check. I'd be happier if it changed up at 6500rpm as that would still keep it in the powerband. Is there any way of recalibrating it? Does the sensor involved measure engine revs or speed or a combination of both I wonder.

 

I am also curious about the overdrive. Did you know for instance, that if you manually select 1 or 2 on the auto box the overdrive switch has no effect (ie it is always off).

And can anybody explain why the overdrive is a 2 stage process? (ie when changing up the revs increase by 500rpm ish for a second or so - sometimes for much longer, then drop by 1000rpm ish - I believe this causes problems when trying to switch the overdrive on at 7000rpm as it would have to go over the limiter before eventually dropping. Or is this just my car?)

 

The hold button normally starts in 2nd gear but if you select 1 it can be made to start in 1st. I find that by selecting 1 and hold it will stay in 1st until I want it to change up, then I slot it in 2 and it will change immediately and stay in 2nd until I want it to change. Selecting D will make it change up immediately. Rather fiddly I know, but still not as much work as you'd do with a manual box

 

I'm still learning how to best use the autobox. I believe I can probably make it do what I want eventually but it is a lot harder to learn than a manual. I learnt a few tricks at Kemble and I'm still learning so my advice is just to play with it a bit.

 

------------------

...but whatever I try my autobox is 1 step ahead of me

Even in Hold mode when I floor the fun pedal it switches into Power mode for 10 seconds (can someone confirm this?) so stopping the gearbox from changing up.

And surprise, surprise, 10 seconds is exactly the time required to get the car from standstill into 3rd gear

 

****ing autobox !!!

 

Originally posted by Simon:

Do you have a stock ECU? As the JWT increases the redline by 500rpm.

 

I'm sure that won't help but there you go!

 

Simon

 

200rpm

 

Sorry posted before reading AndyP's post...Doh!

 

 

 

[This message has been edited by Timmy_Turbo (edited 28-11-2001).]

Having read all the above, I was completely baffled when I got my Z as to what purpose the O/D serves???

 

Having just chopped in an Auto Mk III Supra for it, the Supra would change very smoothly and sharply with O/D off at about 2 or 3K rpm. Even if you kicked it down or floored it with the O/D off it would change at about 4/5K rpm.

 

It only ever went to the redline with O/D on!

 

When I got in my Z and booted it I expected to see the same but it doesn't, it has a complete mind of its own to be perfectly honest. Sometimes it really hesitates, changes and pulls with a surge which is not smooth autobox changing at all!

 

The only time the revs should EVER hit the limiter or redline are with O/D on! That's the whole point of having it, it doesn't allow the box to change until you hit redline at which time it should change you up smoothly and not bounce off the limiter!

 

I am still convinced that mine doesn't behave the way it should, my Supra Auto always behaved and never acted like the Z box at all!

 

 

We need a guide to "How to use the autobox?"

 

Anyone?/

No no no the Over Drive (OD) buttom is just like a 5th gear allowing for more relaxed cruising.

 

The Power button or the box switching to power mode on kick down will allow you to rev to the red line.

 

So in summary;

 

rocker switch on 'Power' delays gearchanges allowing you to use the whole of the rev range.

'Hold' will delay change ups to allow you a smoother power delivery when towing or ICY conditions.

 

The middle position will change up as it feels the need but if you boot it it will 'kick down' into 'Power' mode automatically and will switch out of 'Power' when no longer needed.

 

If yours doesn't act like this then there is something wrong or you've had an upgrade.

 

The lever on the front of the stick will allow you to move the stick without pushing the brake on first. This is handy if you want to roll the car up the drive with the iginition off. It has nowt to do with the 'auto' box setting.

 

Simon

For me the best mode to drive in is; rocker in the middle 'So power light is NOT illuminated, and overdrive off.

 

I tend to hit overdrive once above 80mph.

 

If your in hooligan mode then power button on and O/d off which will give you serious boost and acceleration at over 100mph. Great fun.

 

Hold button?!?!?! Never use it unless you have a caravan!!!!

 

Simon

One extra bit - Timmy's car is a UK, UK cars don't have the "Power/Normal/Hold" switch, so AFAIK it's 'stuck' in Normal mode.

 

Everything else operates as the Jap box though (although the change points are slightly altered)

Used the 'hold' button once when getting my car out of a field, there was slippery wet muddy grass everywhere.

 

It worked very well choosing the highest gear possible and reducing wheelspin.

 

What was I doing in a field in a Z? I'd just been to a fireworks display and it was the car park, it was on an incline too, not very bright really

 

Tim