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The mkiv Supra Owners Club

Speedo converter removal and re-fitting. Help required and possible guide later!!


JohnHandy

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John, lets go back to a few basics.

 

Jspec car?

What is the max reading on the speedo face?

Does it have the K on kph removed or replaced with M? Or is the mph printed on there?

Does the car hit the 112 mph limiter (normally about 120-125mph on the speedo)?

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You're looking in all the wrong areas. It doesn't look like there's one fitted at all, although there is some non-OEM wraping on the ECU wires. The other stuff you've pictures is all alarm related.

 

You need to have a *really* good look at the following plugs and check for splices, primarily the Speddo plug and ODO plugs.

 

http://www.thor-racing.co.uk/images/non_vvti_supra.jpg

 

Ideal that’s a great diagram thought it was the fifth pin on the back of the speedo......will take a very close look and get back to you....

 

Defo was converted.....

 

First thing to fail was the speed limiter can't quite remember how I found that out :innocent:

 

Then intermittent failure between KPH and MPH and total failure!

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You're looking in all the wrong areas. It doesn't look like there's one fitted at all, although there is some non-OEM wraping on the ECU wires. The other stuff you've pictures is all alarm related.

 

You need to have a *really* good look at the following plugs and check for splices, primarily the Speddo plug and ODO plugs.

 

http://www.thor-racing.co.uk/images/non_vvti_supra.jpg

 

Just had a long look there is no splicing at the ODO plug or the speedo other than the oem stuff that i found earlier and the pink ECU wire is not cut and joined at all.

 

The only other option that Dave can suggest is that some madman has installed it at the speed sensor point of origin under the passenger side of the gearbox!!

 

This is flaring up my OCD for everything working correctley somthing cronic!! and yes i can't stand the sterio being on an odd number. (I know i'm a nutter) :(

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John, lets go back to a few basics.

 

Jspec car?

What is the max reading on the speedo face?

Does it have the K on kph removed or replaced with M? Or is the mph printed on there?

Does the car hit the 112 mph limiter (normally about 120-125mph on the speedo)?

 

 

Yes J spec SZ AERO

 

optional extra cruse control fitted.

 

Speedo goes to 180mph and had MPH on it before the elglo dial replacement (fitted by me) and no not right before the speedo failure.

 

Yes it hits the limiter at 120mph approx when it feels like reading in mph. however there was i time when it did not limit (when i was on my local airfield) :innocent:

 

The de-limiter failed first then the speedo.

 

If it feels like reading in KPH it will hit an indicated 80 on the clock then fail needle points to 0 or 20 mph... This should equate to 50mph and feels like about the right speed (50mph)

 

 

:help: :search:

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If it feels like reading in KPH it will hit an indicated 80 on the clock then fail needle points to 0 or 20 mph... This should equate to 50mph and feels like about the right speed (50mph)

 

Well... it might be nothing, but I think the code 42 is triggered at speeds at about 50mph or above. Code 42 is the ECU's error code for what it thinks is a fault in the no.2 speed sensor. This is a pretty common fault, and is almost always caused by a faulty speed converter or a fault in the odometer PCB, not by a faulty speed sensor itself.

 

It's far-fetched, but just possible that the previous owner had this fault, and decided to splice something in around the speed sensor, as Dave or Homer said. That would involve poking around the gearbox, which I've never done so can't really advise you on that.

 

It's a good effort with the photos, but TBH they're not clear enough to recognise anything that's out of place. This is one of those tasks where you really need to be there to spot the DSC (if it is indeed there at all). They're sometimes not much bigger than a thumbnail, and 1mm thick.

 

I'd suggest wait for Dave to have a look at the car: you've looked in all the right places, but sometimes you need an extra pair of eyes.

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Guest Carsten

Wow. My backside of the Speedo looks totally different. With wires connected to screws and so on.

 

...

Trust me, im not happy about changing it back to stock. It will me a mess.

 

Another question ive got:

I have a jspec Sup with the mph count. (i.e. 0-180mph) and a converter from km/h->mph.

http://www.gumball3000.com/files/blog/IMG_0393.jpg seen here (example pic)

If i now remove the converter (so that the speedo counts in km/k) will the numbers on the speedo still match? Meaning if i run 180km/h the speedo shows 180mph?

 

Hope this is understandable

Edited by Carsten (see edit history)
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Well... it might be nothing, but I think the code 42 is triggered at speeds at about 50mph or above. Code 42 is the ECU's error code for what it thinks is a fault in the no.2 speed sensor. This is a pretty common fault, and is almost always caused by a faulty speed converter or a fault in the odometer PCB, not by a faulty speed sensor itself.

 

It's far-fetched, but just possible that the previous owner had this fault, and decided to splice something in around the speed sensor, as Dave or Homer said. That would involve poking around the gearbox, which I've never done so can't really advise you on that.

 

It's a good effort with the photos, but TBH they're not clear enough to recognise anything that's out of place. This is one of those tasks where you really need to be there to spot the DSC (if it is indeed there at all). They're sometimes not much bigger than a thumbnail, and 1mm thick.

 

I'd suggest wait for Dave to have a look at the car: you've looked in all the right places, but sometimes you need an extra pair of eyes.

 

Thanks Steve I'm going to wait I've gone as far as my knowledge allows and the wiring diagrams in the manual are confusing me now!!

 

lots of great info and it all makes sense but like you say I think this needs to be viewed by a second pair of eyes to see what wrong. :(

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Wuss :p

 

What was it then mate, a box chopped into the speed sensor wire giving 5:8 output? If it was then that's a nasty bodge, would have caused all sorts of issues with the ECU :blink:

 

YEP:rolleyes: The three wires from the sensor were chopped into a nasty little box and just left there for the eliments to destroy. I'm sure John will be along shortly to put pics of the offending item up and explain all.:) BTW he was not going mad but did get a bit involved with taking the car apart.

Dave:D

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I'm sure John will be along shortly to put pics of the offending item up and explain all.:) BTW he was not going mad but did get a bit involved with taking the car apart.

Dave:D

 

Me no!! Well I'm glad its all sorted now put her back together last night (2 hrs) bang on! and installed new internal aerial, sorted the light sensor and re-wrapped the loom exactly as it should be ;) putting the little orange box back where i found it :innocent:

 

Took her out for a lil spin ad all good over reading by just under 3% according to the GPS.

 

Dave Your a legend mate thanks so much for your help.

 

No pictures of the offending article at the moment as got the wrong laptop at home.

 

Thank you all for your help support and advice I'm now a lot wiser and verry glad to know I'm not going mad! lol

 

I'm going to tackle my nasty boot popper switch and fog switch tomorrow..... got some nice shiny aluminum switches. :D

 

Homer look forward to meeting you later at Fairmile BBQ.

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