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How To: Install a Speedo Convertor and Delimiter


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How to install a speedo convertor and delimiter

PDF Version - http://www.mkivsupra.net/vbb/attachment.php?attachmentid=105237&stc=1&d=1265986873

'Draft' status until I've drawn up my version of the wiring schematic and added a few extra words about the wiring.

 

This is my first ever ‘how to’ write up, so be gentle! :)

 

Any questions or if you spot anything I’ve missed or that isn’t clear, please give me a shout and I’ll add it in/see if I can address it.

 

 

How To…. Install a Thor combined “Speedo Converter and Top Speed Delimiter” to a pre-facelift mkiv Supra.

The unit is available from here.

 

Note: Top Speed Delimiter (TSD) is also known as Speed Limit Defender (SLD)

 

What you will need:

  • Between 2 hours and anything up to a full day depending on if you’ve done this before. Anyone who can use a screwdriver and read a schematic can do this, just be patient and allow for the fact it might take you a while – i.e. don’t start this if you need to drive somewhere in an hour. :D
  • A metre or two so of decent electrical wire to extend the TSD wire down into the passenger footwell where the ECU lives
  • A Philips (X-head) screwdriver
  • Wire cutters
  • Wire strippers – I recommend decent ‘automatic’ ones as you have limited lengths of wire to work with and can’t afford to make mistakes!
  • A socket set to get at the ECU
  • Heat shrink (and something to heat it with) for a proper job of covering joined wires & providing strength, or insulation tape as a second best.
  • Insulation tape as well as the above to;
  • -Fasten wires out of the way to keep everything tidy and avoid weight transfer putting any stress on the joins you’ll be making
  • -Tape the unit itself to something so it won’t rattle around
  • -Insulate 3-way joins (splicing) & any joins where heat shrink just doesn’t fit
     
    ...and either…
  • Solder & soldering iron to join wires together. Although a good solder join is ideal compared to the alternatives, be careful – you’re working in tight confines with a hot iron that can easily burn through wires you didn’t mean to touch or mark previously immaculate dash panels or drop blobs of hot solder into the dashboard inners/carpet/your legs, lol.
    …or…
  • Some decent electrical connectors instead. NB: I’m happy to take advice here as I used the solder approach, but I would suggest bullet connectors or spade connectors, not terminal blocks. Whatever you use, make sure it’s a) solid , and b) insulated so it can’t short to anything metal or another wire/connection.

 

Before you start: Advice & ‘Lessons Learned’ from when I did it!:

  1. Be. Very. Patient. Remember how much you love this car, I’m talking mainly here about removing the dash panels – unclipping the connections to the instruments and especially the console items can be an utter, utter b*stard to fathom out be really is quite simple once you get the hang of it. To try to save you the pain I’ve described them all in detail in the ‘connectors’ section. Be warned, I am extremely patient but it is still very easy to get angry and frustrated and start yanking at things, don’t. Go make a brew and come back later instead!
  2. Check and double check everything you plan to cut before cutting it. I didn’t make this particular mistake but you could easily mess things up and/or spend a lot of your time fault-finding by rushing into the task and getting it wrong. Also take a moment to consider the best position along each wire to cut it; this will depend on whether you will need to work with both ends or just one, and whether you’re connecting in a 3rd wire from the chip or not. Usually you will have too much wire coming from the converter chip and may want to consider trimming it back slightly, so everything is tidy.
  3. Don’t expect it to work fully the first time you put it all back together, even if you’re positive you’ve done it all correctly. Just 1 messed up connection will lead to spurious outcomes, so my advice is don’t tape all your connections up and don’t bother to screw all your dash panels back in at the stage you think you’re ready to roll. Simply push the dash panels back into their positions so they won’t go anywhere and take it out for a test drive (see test drive below). It takes less than 5 mins to get the dash out if you do this in order to then make everything tidy, rather than the hour plus it’ll take you to remove the dash and insulation tape so that you can start the fault-finding.
  4. Don’t wear shorts or anything synthetic if you plan to solder. Really, really watch where you put that thing when it’s hot! :D

 

Before you begin:

Please note that your trip 1 and 2 odometer readings will get reset to zero when you remove the connector (which supplies the power) to the odo unit. If you depend on these to remind you of service/oil change intervals or something, note them down before you start. The odo reading (your vehicle’s mileage) however is stored in non-volatile memory and won’t be affected (or reset to zero, sorry ;))

 

Go for a drive near to you. Reset a trip counter as you set off and note where you are when 1.6 kilometres racks up. After the job is done repeat your course and if all is well your trip counter will read 1.0 (if you choose to convert it to miles that is!). During the drive, note revs Vs speed, e.g. how fast does your speedo read if you going at 2,500revs in 3rd gear? Remember this, and compare it after the conversion for a quick check to see if it works as expected (e.g. 50kph = 31mph). You might want to document (film) this process to aid selling the car in future, to prove to a buyer when the speedo was converted and what the odo reading was.

 

If you have an airbag, I believe you should remove the battery connection before removing the dash as you’ll get reports of an error afterwards if you don’t. I’ve seen notes about this and how to fix it if you forget but it didn’t affect me as I’ve not got an airbag. However before you unplug your battery(!), consider; will it affect your alarm and/or stereo?

How To_ Install a Speedo Convertor and Delimiter.pdf

Edited by JustGav (see edit history)
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Step 1 - Removing the dash:

Combine Heckler’s guide, here with the pictures in the ‘Connectors’ section below so you can see how each panel’s instruments are attached to make the job as easy as possible. If you have the stock dash covering be very careful not to scratch it, especially mind the main dash panel rubbing/catching on the steering wheel tilt lever as you remove that panel; it’s easy to scratch it without realising… like I did.

 

Connectors:

Top panel – there are 2 connectors on the left (hazard warning switch, left hand warning lights cluster) and 1 on the right (right hand warning lights cluster). You should be able to lower the panel enough to get at these quite easily. They undo by pressing the central clip down, into/towards the connector.

image

Top dash panel, right hand connector

 

To remove the larger dashboard panel - the one with the clock, cigarette lighter (power, surround light), 2 x heater controls, “slip cont”/similar, I found working from top to bottom easiest…

 

Clock – undo by pressing (inwards towards/into the connector) the clip located half way down the side of the connector.

image

Clock (rear)

 

Cigarette lighter (2 connectors) - pull the L shaped connector backwards (away from you & towards the engine) to remove. the light twists through 90 degrees then should pop out.

image

Cigarette lighter, power connector

 

image

Cigarette lighter, light

 

image

Cigarette lighter (rear) - shows L-shaped power connection and above that, the 'socket' for the light

 

Heater controls (2 connectors) - Press the top bit of each clip (in the middle of the top of the connector) downwards.

image

Heater control connectors (2)

 

Slip Cont/etc - get a screwdriver as this a real pain, and press firmly downwards against the clip in order to remove (see pic).

image

"Slip Cont" button, rear - use screwdriver to prise connector away (already removed)

 

image

"Slip Cont" button connector

 

Removing the instrument cluster is pretty simple & easy (refer to Heckler's guide). Remove the central dash panel (that encloses the instruments) unscrew the instrument cluster (2/4? screws at the sides), detach the 3 connectors from the back and remove the instrument cluster.

image

Instrument panel connectors - blue, brown, white

 

image

Instrument panel, rear - 3 sockets along the top, 1 for each connector

 

image

The removed instrument panel (note "k" already covered up in speedo section (see step 5 below))

 

Step 2 – Fitting the Speedo Convertor:

As mentioned above, don’t expect this to work first time. It is galling to fit, insulate and replace everything perfectly only to find that it doesn’t work for some reason. Instead, I suggest you make the connections by simply twisting together the wires you wish to join and temporarily cover each connection with an easily removable piece of insulation tape. If it all works come back and do the job properly, if it doesn’t you can begin fault-finding straight away and have saved yourself a LOT of effort undoing patiently soldered/connected wiring. Believe me, it’s annoying! lol

 

Connect the wires in any order you want, by following this schematic.

(A better one will follow; I’ll draw one up that is a bit simpler & easier to read, ASAP)

 

Note the different configurations you can achieve regarding the speedo/odo reading in Miles or Kilometres depending on how you wire it in (not shown here but will be shown on the better diagram).

 

Once you've done the main power, speed input, speed & odo outputs, connect a decent length of electrical cable to the TSD wire coming from the chip, to extend it into the passenger footwell. Simply route it past the heater outlet pipe and aim it towards the passenger footwell, you should easily find a route through, just don’t put it anywhere that might catch/rub/strain the wire; think about where the dash panel and its connectors will need to go.

 

Step 3 – Wiring in the TSD:

If you want, you can leave this until after you’ve tested the speedo converter is working properly, just note that you will get an ECU warning light appear after a short distance as its confused that the speed readings it’s receiving don’t match up.

 

This bit is extremely easy compared to the speedo/odo work...

 

Remove the passenger side “kick panel” the piece of plastic (that has a holder for the flare on J-Spec models) that joins onto the sill that runs the length of the door. These 2 pieces are connected together and it’s easier to just pull both out in 1 go than try to separate them; use a screwdriver to poke the centre of the circular thingy holding the kick panel in place and retain for refit later. The rest of the panel and door sill just lifts out of push-clips with a little persuasion.

 

Pull back the carpet by grabbing the bit nearest the engine end of the car and pull back towards the passenger seat (shove the seat right back to give you most room to work with). You should now see the ECU cover (see pic). Remove the 2 nuts at the bottom using a socket and pull the cover off. You should now see the ECU in all its glory (see pic).

image

ECU (cover removed)

 

Don’t bother trying to remove the wiring harness from the ECU, this isn’t necessary. Locate the wire coming from pin 2 (pink, almost top right in the section of ECU connector closest to the seat) and snip it leaving a sensible amount to work with.

 

Wire in the 'extension' you brought down from the chip to the ECU stub of the wire you just cut. Tape up the original wire (loom side) to keep things tidy.

image

Modified ECU wiring - extension from Thor delimit chip spliced into the pink wire coming from pin 2, original loom end wire with bare end can still be seen

 

Step 4 - Test Drive, aka “how to test you’ve done it all correctly!”:

Connect all the dash items back up to their connectors and push all the panels back into their respective places. You don’t need to worry about the clock/heater controls/ciggie lighter if you don’t want to but ensure you do connect things like the hazard warning light connector as the indicators don’t work without it!

 

Go for a drive, see how long it takes to clock up 1.0 on the trip counter, see if the speedo reads a sensible amount, drive for at least a couple of miles at a variety of speeds/gears and check to see if any warning lights come on.

 

Note: You can do this bit before wiring in the delimit to the ECU, but if you do though, you’ll see the engine management warning light appear once you get up to 50~60mph as the ECU is seeing a different speed to the rest of the car’s electronics.

 

Step 5 – Modify the Speedo:

Remove the instrument cluster (speedo, revs, fuel gauge etc) and detatch the clear front cover by carefully prising apart the many clips along the sides.

image

Instrument panel, clear cover retaining clip (1 of many)

 

Cut a tiny peice of black insulation tape to size and stick it over the "k" of "km/h", so it reads "m/h". Check it's all dust-free (won't break anything but dust is annoying and spoils the appearance) and put it back together.

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Step 6 – Tidy up:

Assuming you’ve got everything working, remove all the dash panels again and now make the connections properly; insulating them as you go. Once that’s done, use insulation tape to collect up and fasten wires out of the way and keep everything tidy, ensuring that there is still enough slack where it is needed (e.g. to bring the connectors back to the dash when putting it back together again.)

 

Use tape to secure the chip itself too – ensure it has no room to rattle about and that it is out of the way of everything else, see pic for where I positioned mine.

image

Suggested chip position

 

Again, use tape to secure the ‘extension’ wire that feeds into the ECU at convenient points along its path. Replace & refit the ECU cover, carpet and kick panel.

 

Go for another test drive to check everything again.

Job done! :clap:

 

 

'Annex A': Potential faults from their symptoms:

(how do I do a proper table??)

 

Symptom                                Potential Causes (likely order)
Speedo and odo are completely dead     1) Chip has no power – bad connection/bad earth
                                      2) Bad connection from chip to speedo connector
                                      3) Chip faulty/not programmed
                                      4) Speedo/odo connectors not reconnected properly

Speedo dead, odo/trip counters work    1) Bad connection from chip to speedo
                                      2) Speedo connector not reconnected properly
                                      3) Chip faulty

Odo dead, speedo works                 1) Bad connection from chip to odo
                                      2) Odo connector not reconnected properly
                                      3) Chip faulty

Intermittent operation (any feature)   1) Bad/loose connection at the affected item (e.g. odo/speedo/TSD)

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  • 4 months later...

question, if I dont' want to convert the ODO or speedo to MpH and leave it reading Km/h since I live in canada, can I leave out that black wire connecting the blue(red stripe) coming from the odometer to the speedometer? or would it be easier to just not connect the white (5:8) wire?

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When I did this mod a few years back the Thor unit had a trimmer inside it which allowed you to calibrate the speedo. I imagine the design hasn't changed. If you've got a Road Angel or similar GPS speedo you can make your normal speedo accurate - they normally read faster thean reality. If you've mounted the unit in the footwell you'll need an assistant to help - my advice is locate it under the gear shift panel. You tweak the trimmer while holding a steady speed and match the two speeds. Good article - and it is very annoying when you put the dash back together and something no longer works!

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question, if I dont' want to convert the ODO or speedo to MpH and leave it reading Km/h since I live in canada, can I leave out that black wire connecting the blue(red stripe) coming from the odometer to the speedometer? or would it be easier to just not connect the white (5:8) wire?

If you don't want to convert anything, just buy the delimter chip and save yourself a few quid (the combined delimit AND convertor costs a bit extra).

 

If you do want to convert either the speedo or the ODO, but not the other, you just connect whatever you want to stay in KMs to the 'unfiddled with' signal (the BLUE wire).

 

Next week (promise!) I'll get the schematic finished off, add a few words about which wire goes where, and include the options you have regarding speedo/odo reading in Kms/Miles, too.

 

When I did this mod a few years back the Thor unit had a trimmer inside it which allowed you to calibrate the speedo. I imagine the design hasn't changed. If you've got a Road Angel or similar GPS speedo you can make your normal speedo accurate - they normally read faster thean reality. If you've mounted the unit in the footwell you'll need an assistant to help - my advice is locate it under the gear shift panel. You tweak the trimmer while holding a steady speed and match the two speeds. Good article - and it is very annoying when you put the dash back together and something no longer works!

Thanks for that - I wasn't sure how you calibrate the output signal. One thing that bugged me was, I didn't notice any adjustor in mine - the only thing that looked remotely possible was something with jumper switches, but I may be way off and what I saw wasn't anything to do with calibration. It's a shame if it's not adjustable as it cleared stated that it was in the advert when I ordered mine. Mind you, my speedo seems pretty accurate compared with a GPS readout, so it's not an issue unless I change the wheels for something with a different rolling radius...

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  • 1 month later...
Guest Busaking

Hi guys, i have a jap spec supra that was converted to mph when it arrived in England, I purchased it and brought it back to Ireland where the EU has deemed necessary to enforce KPH upon us. I removed conversion chip and speedo works in kph but odo is reading in mph and clocking up a mile for every kilometre.What do i need to do to put odo back to Kph? Thanks for reading!:)

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Hi guys, i have a jap spec supra that was converted to mph when it arrived in England, I purchased it and brought it back to Ireland where the EU has deemed necessary to enforce KPH upon us. I removed conversion chip and speedo works in kph but odo is reading in mph and clocking up a mile for every kilometre.What do i need to do to put odo back to Kph? Thanks for reading!:)

Hmmmm.... are you sure you removed the chip? J-Spec odos work in km without a converstion chip, so if you removed it it can't count in miles. Stupid question but are you sure it a J-Spec?

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Guest Busaking
Hmmmm.... are you sure you removed the chip? J-Spec odos work in km without a converstion chip, so if you removed it it can't count in miles. Stupid question but are you sure it a J-Spec?

 

I removed the conversion chip for sure,a jap import for sure even have yen funny money from under carpet.She is happily clocking up a mile for every Km driven.I wonder is it an ecu modification or possibly reverted back to Km by way of software manupilation.

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I removed the conversion chip for sure,a jap import for sure even have yen funny money from under carpet.She is happily clocking up a mile for every Km driven.I wonder is it an ecu modification or possibly reverted back to Km by way of software manupilation.

Hmmm... I have no idea on that one, sorry!! :blink:

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  • 4 weeks later...
Guest jasoneverettbro

Hi Steve,

 

I have just been reading your thread and wondered if you could answer me a quick question?

 

Would this process work if I wanted to switch a 120mph Jspec speedo (now de-limited) to the 180mph speedo?

 

I'm not mechanically minded so be gentle with me. Any advice would be very welcome.

 

Cheers

Jason

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Hi Steve,

 

I have just been reading your thread and wondered if you could answer me a quick question?

 

Would this process work if I wanted to switch a 120mph Jspec speedo (now de-limited) to the 180mph speedo?

 

I'm not mechanically minded so be gentle with me. Any advice would be very welcome.

 

Cheers

Jason

Hi Jason :welcome:

 

Can you post up a picture of your speedo jus so I'm 100% sure what it is we're looking at? - I'm assuming it's labelled in mph and that 120mph is at about the 5 o'clock position?

 

The convertor takes in the original (kph) signal and send out a 5/8ths version of it (mph); so it you think about it like that.... imagine you're driving along at a set speed (forget kph/mph for the time being - just an arbitrary set speed). Now think about the speedo position; compared with it's position prior to a conversion chip being gfitted, the speedo needle will points only 5/8ths of that 'sweep' round the dial after the conversion.

 

Badly worded I admit, but does that make sense?

 

The short story is, - TBC once I've seen your speedo picture - you'd need to change the units or the scale of your speedo; most likely through changing the speedo face itself.

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Guest Jarl Ayari

Which speedo converters have a calibrate pot on them as the one I have fitted at the moment doesnt read right in miles or KM. With the converter its reading 15 mph high on the km scale and with it out it reads rediculously low.

 

Andi

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Which speedo converters have a calibrate pot on them as the one I have fitted at the moment doesnt read right in miles or KM. With the converter its reading 15 mph high on the km scale and with it out it reads rediculously low.

 

Andi

The Thor one (linked at the top of this thread) is supposedly adjustable but I never saw how whilst installing mine - unless it's by adding PC-like jumper thingies or similar - give them a call and ask?

 

Apart from that I personally have no idea which convertors are worthy of being fitted as many (usually the cheapo ones) will cause you issues.

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Guest jasoneverettbro

Hi Steve, thanks for that. Its all a bit over my head but hopefully the pic will clarifly which speedo. I won't be upset if you talk to me like I'm stupid.

 

Thanks again for your time.

 

Jase

speedo.jpg

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Hi Steve, thanks for that. Its all a bit over my head but hopefully the pic will clarifly which speedo. I won't be upset if you talk to me like I'm stupid.

 

Thanks again for your time.

 

Jase

Verdict after seeing the photo - it's as I expected and you will definitely need a new speedo face. Try and get hold of a standard one (maybe speak to Jezz on here who breaks Supras) or if you have plans for fancy glowing and/or steel-faced dials one day, now would be a good time to get them.

 

If you fitted the convertor now, the speedo would be meaningless - it simply doesn't have the correct range on it (compare it with the photos of when I fitted mine, above). Sorry chap! The only thing you could do wtih that face - and it'll look cr4p - is cover up ALL of the larger 'outside' numbers and use the inner numbers as the MPH (not the KPH they currently represent). Doing that would be correct, but it'd look rubbbish.

 

How far into Devon are you (relative to the North)? I might be able to lend ahand if you find yourself well & truely stuck.

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Guest jasoneverettbro

Thanks mate, still it still sounds that if I get hold of a 18omph speedo + the converter then it should work with out any major alterations to the transmission. Is that right? Thanks though you've been a great help. I live between Exeter and Honiton so not a million miles away.

 

Cheers bud

Jase

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Thanks mate, still it still sounds that if I get hold of a 18omph speedo + the converter then it should work with out any major alterations to the transmission. Is that right? Thanks though you've been a great help. I live between Exeter and Honiton so not a million miles away.

 

Cheers bud

Jase

Yeah if you get hold of a speedo that has 180(anythings) written in the same location as your 110mph on your current speedo, you're on a winner :)

 

If you need a hand sometime and don't think I'm too far from you - just give me a shout.

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  • 3 weeks later...
  • 2 months later...
Guest ulysses31

I have the following issue after fitting the combined thor delimiter and speedo converter:

the odemtre is now working correctly - messuring miles not kilometres.

But the speedo is counting miles per hour on the inner ring (kph) not the outer (mph) ring....

Any one any ideas where ive gone wrong ? quick reply would be apreciated.

thanks

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