Jump to content
The mkiv Supra Owners Club

Indecisive autobox TC lockup


carl0s
 Share

Recommended Posts

I have asked this before but didn't get any answers, so here goes again.. :)

 

I can feel my J-spec car slip in and out of TC lockup at very-light-throttle cruising between about 56mph and 62mph. It's like a little gearchange is going on, quite frequently.

 

I'm most sure my UK car didn't do this, and I would expect there to be some kind of fuzzy-logic in the ECU to make it basically stay in lockup with such light throttle at obviously cruising speeds.

 

My speed convertor appears to be some weird rectangle box (labelled Inter**** (Interpro - ?)) with four wires attached directly to the screw terminals in the flexible flat pcb on back of the speedo gauges, and as far as I can tell, everything else works properly (active spoiler comes down when it should, and I don't see any other oddities with the gearbox).

 

The car doesn't seem to have a speed limit either, as we hit an indicated 175 on the M6 toll road on the way to Flame and Thunder, but I've not actually looked for an SLD or anything. I'll be fitting my Thor FCD soon when the Fields harness arrives and will obviously have a closer look then.

 

Can anybody shed any light?

Link to comment
Share on other sites

Hmm. This car had a gearbox rebuild costing £1,400 not long before I bought it. It didn't need the rebuild, but the garage misdiagnosed the dodgy facelift engine-mounts as a dodgy gearbox.

 

I suppose they could have done something funny whilst they were in there :eek:

 

Keep the ideas coming please guys, I don't like the sound of the above :D

Link to comment
Share on other sites

Mine was slipping in and out of Lock Up, but i put that down to all the changes i made after going single. I wonder if one of the plugs of the box has come loose and isn't making 100% contact.

 

Oh hang on, when you said 'all the changes you made', did you just mean changes to the car?

 

I thought you meant all the gearchanges you made with all that extra power, i.e. knackered box.

 

Are the plugs easy to get to?

Link to comment
Share on other sites

First instinct would be the speed converter Carl.

 

Either remove it completely or put a THOR one on.

 

I've got a wiring diagram for an "Import Solutions" speed converter, if it's one of those.

 

Dodgy connections and crap speed converters account for about 90% of all these type of problems

 

I think you're probably right Geoff, thanks.

 

I'm fairly sure it was "Inter-something". It's a small aluminium box about the size of a cigarette lighter, with black and green painted lines down it, I think.

 

I'll try to get a better idea what's wired up to what this week and think about grabbing a Thor unit.

 

It's not as if this problem is really obvious, I think I'm just aware of it and I notice it - other people probably might not notice it immediately.

Link to comment
Share on other sites

  • 1 year later...

The car doesn't seem to have a speed limit either, as we hit an indicated 175 on the M6 toll road on the way to Flame and Thunder

 

It'll probably kick in at 180mph, as the ECU thinks it's 180kph due to the speed convertor. 180kph is the 112mph limiter.

 

Mine was like that :D

 

-Ian

Link to comment
Share on other sites

  • 3 months later...

sorry to dig up an old thread but this seems the most relevant, im going through the problems with my supe, i thought i had most sorted but as of yesterday they came back, i think my speed converter is mainly to blame but im curious about this gearbox lockup?

 

right as im going up the gears in D (na auto) at light throttle it goes 1-2-3-4 but when im driving abit harder it goes 1-2-3 then clicks in to 4th but the revs only drop by 2-300rpm at tops but if i lift off it pulls fully into 4th, and when on the motorway i give it some gas to overtake it gives a good 'kickdown' but the box doesnt change down it just kicks the revs up and then hold them 2-300rpm lower that 3rd gear would, switching od off at this point kicks it down into 3rd it feels like it has a 3.5 gear witch i know it doesnt

 

it only seems to do this when the O/D off light is flashing, it flashes randomly but once it starts it doesnt stop untill next restart

 

i have searched alot but dont seem to be turning up answers anyone experienced similar?

Link to comment
Share on other sites

OD off light flashes when a speed cannot be detected from one of the speed sensors. It did this on mine and also gave me an engine warning light everytime I would reach over ~60-80mph somewhere.

 

I think the error code points it to speed sensor 2 or something like that (sure someone will correct if wrong)

 

I found it to be a lose wire from where the speed converter/delimiter was spliced behind the odometer.

Link to comment
Share on other sites

OD off light flashes when a speed cannot be detected from one of the speed sensors. It did this on mine and also gave me an engine warning light everytime I would reach over ~60-80mph somewhere.

 

I think the error code points it to speed sensor 2 or something like that (sure someone will correct if wrong)

 

I found it to be a lose wire from where the speed converter/delimiter was spliced behind the odometer.

 

cheers for that, my speed converter and delimiter are coming out this week, im convinced its them it did seem to cure it using the code 42 error fix i found but then it came back, i thought the gearbox problem was separate (if it is a problem) it bugs me lol im going to sort it one by one if it take for ever lol:d

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.