Jump to content
The mkiv Supra Owners Club

Where's my speed converter?


stevie_b

Recommended Posts

Like it says in the title. My speedo reads up to 180MPH, so I'm pretty certain there should be a digital speed converter around somewhere. I've taken the passenger footwell carpet up and ECU protective panel off: nothing that looks like a DSC.

 

I've got my dash and speedo/tacho dials off: nothing behind there that looks like a DSC, unless it's REALLY well hidden.

 

There are two plastic boxes (orange and brown, if I remember correctly) on top of the head unit cage, but I remember reading somewhere that these are nothing to do with speed conversion.

 

I assume I'm looking for a small-ish plastic box, maybe an inch or two thick. Is there a fool-proof way of finding the location of the DSC?

Link to comment
Share on other sites

They're usually a small box about the size of a matchbox. Most often wired into the ECU harness.

Some of the cheaper ones are very small. I've seen one no bigger than my thumbnail. Are you sure it hadn't been tucked behind the ECU or somesuch?

Link to comment
Share on other sites

:bump:

 

An update: me and Gav had a look around behind the speedo dials the other day, and found *something*. I don't know what the hell it is: at first we thought it was the speed converter, but now I'm not so sure. It's a black rubberised "thing", about 3 to 4 cm long, 2 cm wide, and very thin (maybe 2 or 3 mm thick) behind the speedo dial. It hangs free (not bolted to anything) apart from 4 wires coming from it. One of them's blue, which doesn't go anywhere (just left floating), and I think the others are white, green, (and can't remember the colour of the last one). I think the green wire's grounded via the screw at the back of the speedo dial, and the white one disappears into the speedo dial's guts. I'd post pictures of it, but don't have a digital camera or camera phone. I'll try to borrow one....

 

What makes me think it's not a speed converter is that is doesn't take any signal off of the no.1 speed sensor (red/blue wire with silver stripes), unless the white wire is the no.2 speed signal?

 

I'd appreciate any help that anyone can suggest. My car's off the road until I can find the speed converter. :(

 

Thanks in advance!

Steve

Link to comment
Share on other sites

Does anyone know if the speed converter is *always* plumbed into the No.1 speed sensor wire?

 

Edit: Jake: I've had another good look around the ECU in the passenger footwell, and I couldn't find anything that looks like a speed converter. Thanks for the suggestion though. All help/ suggestions gratefully received! :)

Link to comment
Share on other sites

my converter was fitted on top of the auto gear box was well hard to get at had to jack the car up and crawl under to get at it it was fitted by j i c have now got a trl one fitted behind the dash

Link to comment
Share on other sites

An update: me and Gav had a look around behind the speedo dials the other day, and found *something*. I don't know what the hell it is: at first we thought it was the speed converter, but now I'm not so sure. It's a black rubberised "thing", about 3 to 4 cm long, 2 cm wide, and very thin (maybe 2 or 3 mm thick) behind the speedo dial. It hangs free (not bolted to anything) apart from 4 wires coming from it. One of them's blue, which doesn't go anywhere (just left floating), and I think the others are white, green, (and can't remember the colour of the last one). I think the green wire's grounded via the screw at the back of the speedo dial, and the white one disappears into the speedo dial's guts. I'd post pictures of it, but don't have a digital camera or camera phone. I'll try to borrow one..

 

That's it m8, same model converter i use. It's actually a printed circuit board wrapped neatly in heat shrink black plastic. I never bolt them in either - just cable tie them somewhere neatly.

 

It will have:

 

a red & black (+/_) connected to 2 screws on the back of unit with ring connectors.

 

Orange (input to chip), usually connected to the km/h pulse from loom

 

green (mph pulse out) - connected to speedo

 

blue - used as a speed delimiter on some cars, not often requred.

 

Not sure of the wiring diags on a supra, have never done one myself but if it helps I can get you an identical replacement or a wiring diagram.

Link to comment
Share on other sites

Thanks for the help guys, I really appreciate it!

Toytown: if you have a wiring diagram handy, that would be great. Could you upload a link to it or something? I've got a speed sensor error on my supra, and I suspect the speed converter is at fault.

 

Thanks very much!

Steve

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • 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.