MPH to KPH Question

[rabscott2003]

The speedo cluster is new and the rpm and other dials work why does the MPH dial not work and the trip computer?

[rabscott2003]

The guy i bought the car from said he got the speedo swapped from KPH to MPH but it did not work and the KPH started to go on the blink. He said he paid another £150 for a new cable from the speedo to the gearbox. How does the Speedo work on the MR-S is it really ABS computer?

[frogger]

Hi there,

Rip out the clocks and have a look round back if you haven't done already. The cheap kph/mph convertors that clip onto the wires are known for going on the blink, and any dodgy connections will make the whole lot stop working altogether (As will any loose connectors into the clocks themselves).

It's probably been checked, but its definitely worth a look before paying out any money for parts - only a couple of screws involved.

[Cap]

He said he paid another £150 for a new cable from the speedo to the gearbox.

There is no Cable from the Gearbox..   The Spedo is Electric and runs like the Tack.

How does the Speedo work on the MR-S is it really ABS computer?

No the Electric Signal is Taken from the ABS Computer..  and if the Main ECU ( Engine Ecu ) was not receiving that Speed Sig from the ABS Computer, you'd be getting a Cel..  

Cap

[rabscott2003]

I took the dial off and i noticed the wire into the back are ok apart from the set of cables going into the scart like socket on the fuel gauge right hand dial with all the engine light etc one of the wires has been clipped in half and taped its red and white, it has been halfed and insulated tape has been put on each end.
I will take pictures of the back for you.

Also when i disconnect the speedometer side left hand side of the set of 3 the trip computer still works. There is no convertor i can see of and i spoke with a few garages in auto electrics and none of them want to take on the job, so i am stuck unless there is an expert in auto electrics for the MR2/MRS.

The speedo dial might be faulty but the guy i bought it from said it was a new dial which cant be the case as the dial trip computer would have been Zeroed to my knowlege and not have 84000miles on it. I think it is an old cluster. Only other things i can think of is the ABS sensors that read the speed are not working bacause the ECU must be ok no lights are coming on everyday only now and again but does not flash only comes on after 10 miles, but saying that some days it does not come on at all.
Can anyone help?

[rabscott2003]

Here are the wiring pics i was talking about  m http://s925.photobucket.com/albums/ad95/rabscott2003/ m

[rabscott2003]

[rabscott2003]

that last pic was the dial working with the engine on all fine and both RPM counter works and all gauges apart from the Speedometer and trip computer although the trip computer is always on it never clocks up the miles.

here are the rest



































the car is this

[rabscott2003]

Interestingly enough i found this out,  m http://www.car-handbooks.com/Speedos/Co ... verter.htm m

I think with looking at my pictures you will see a black box with SP1A on it this box i think is not suitable for the convertion. The link above you can see how the convertor is fitted quite easily, but i must say the person who fitted mine did not soldier any of them just twisted them and taped them up. I think this is the problem here. I think all i need to do is to repair the wires with a soldier kit and then put this convertor box on but also replace the clock dial with a new sticker.

Any thoughts?

[rabscott2003]

If someone who has an MR-S could take some pictures of their wiring of behind the clocks with the convertor this would be great to see just how it is supposed to work as i really do think mine has been done by an amateur with using the wrong convertor box. Although all the other dials works fine if i could repair the wires buy a new box this might fix the problem. If it still fails it might be a case of the sensors at the ABS either that or the clock might be faulty as apartently a garage done the clock conversion and said it was new but with 86000 or so miles on the trip computer which you can not apartenly change it is unlikey it is new. If i could swap my clock with a KPH i would and just repair the wires i dont know why people need mph i can easily convert in my head as i used to race abroad on bicycles. 8km 5 m 16km 10m etc etc

[frogger]

Right, here goes...

Have been out and looked at my wiring (also an import, with a correctly fitted converter).

Here's the difficult part - my converter has differently coloured wires, and it's only got 4, rather than the 5 on your SP1A unit.
For a quick fix, I'm inclined to recommend you ditch the 5 wire SP1A unit and buy one with the same colours as mine to save faffing around (they're quite cheap on eBay). Not saying you can't get the SP1A to work, and I've given some pointers for using this unit in the footnote at the bottom of the unit if you want to try - but I don't know what to do with the 5th wire, and I think its best to go 4-wire!

All of the wiring below whould be tapped into the RIGHT MOST connector when looking at the steering wheel.
i.e. the connector that clips in behind the fuel gauge NOT behind the speedo (as you would otherwise expect!).
The wiring should go as follows...



The key thing about this wiring is that the Red wire with a White stripe should NOT be broken, just tapped into, as should the white wire with black stripe.
These just provide a +ve and -ve power source.

The only cable that is completely cut into should be the yellow one (with tags) this should be re-routed to go 'in' to the convertor (via the yellow cable) and back 'out' into the clocks (via the grey cable).

It's not a problem that they've already cut ones which should only be tapped into, obviously these can be rejoined.

If you want a pro job then soldering is a good plan. Crimp on connectors are fine too. And to be honest, because there's no real movement of these wires, simply meshing the strands, and twisting is good enough too!

When I needed to complete an engine swap on my old daily driver in time to get work the next morning, I once spliced a WHOLE wiring loom (30-40 wires?) together using this method   s:lol: :lol: s:lol:  still works fine! You just got to make sure you don't let and strands pierce through the insulating tape and short on anything else.

I took pics of my converter wiring if you need them - but to be honest I think the pic above is clearer (hard to believe I know!)

Remeber to do all wiring with the battery disconnected  s8) s8)   lol

Footnote:
5 wire SP1A unit has a red and a black wire. These will be a +ve and -ve supply, so can be wired in the same way as the 4-wire unit ('tap' into existing cables rather than cut entirely for these wires) However, I'm confused by the remaining 3 wires! One should be and 'in' for the ecu signal and one for an 'out', but why another?!

[rabscott2003]

I think i will need to reconnect the red and white wire as the person has cut it in half and left it disconnected with tape on it. Dont know why.

Thank you for the great advice to be honest i am going to buy a convertor and do your wiring program. It seems easier.

Robert

[rabscott2003]

Hi Frogger i just wanted to ask what convertor should i get as i seen this one here:-  m http://www.car-handbooks.com/Speedos/Co ... verter.htm m

[frogger]

That one will certainly do the job, though IIRC any of the ones on ebay such as this  m http://cgi.ebay.co.uk/TOYOTA-SPEEDO-CON ... 0461112146 m  do the same for £10+ pounds cheaper. (£30 INC P&P rather than £40 + P&P)  s8) s8)  

I think there's only a couple of Jap brands (Nissan and Mazda) which use a different electronic converter.
Any electronic Toyota one should do, but the seller of the one in the ebay link above does request you "State model and year when you order" so looks like they'll make sure you get the right thing anyway.

[rabscott2003]

Since my clocks cluster MPH model were changed from the KPH cluster and have different milage on them ie the KPH orginal when car was made in Japan was sitting at 130000km the clock went faulty and then was changed to a second hand MPH clock with 86000 miles on it with that SP1A convertor do i still need the convertor with the MPH clock?

[frogger]

Hmm, Good question!

I missed that change of clusters when reading through your initial posts.

In short - I dont know if you'll actually need a converter or not with that set-up (jap ECU, UK clocks).

It wouldn't hurt to take off all the SP1A stuff, put the wires back to 'stock' and give it a go and see.
It should give you a speedo with a needle that moves at least (an improvement on the current situation!) but I couldn't guarantee it will read in mph properly til you give it a go!
Theres a good chance it may do, and if it does you've saved yourself £30.

Certainly in jap import Honda's swapping the clocks to UK spec clocks works without a converter, and those Honda's use the exact same converter units IIRC.
What this DIDN'T do was remove the 112mph speed limiter (It's quite common for Jap cars to be limited to 112mph, and a fix to this is the speedo converter chip which bumps the limiter way up to 180 or so.) - BUT this was because the clocks were a feed wrong side of the ECU in the Honda's.
To de-limit and convert the speed in these cars you had to fit the chip gearbox side of the ECU (clocks side just converted IIRC).

Because the MR-S does not suffer from this problem (converter on clock side also delimits), it may be that a change of clocks to UK spec also does the same job.
To be honest at the moment I'm struggling to recall if the MR-S even has this limiter, but most Jap imports do!

Maybe thats another bridge to cross when and if you come to it - may not be a problem!

When I'm driving I've usually got another limiter fitted in the passenger seat, gives me an ear full at around the same point the stock limiter cuts in...  s:lol: :lol: s:lol:

[frogger]

Been thinking some more in light of the cluster change, and I'm now wondering if your SP1A box was a failed attempt to breach a delimiter but keep UK clocks.

On closer inspection the 5'th wire seems to be going to the violet-with-white-stripe cable - which is the speed signal for the ECU (and as such controls the speed limiter).

Maybe the SP1A box just monitors the signal from the ABS (the car's yellow wire) and doesn't modify it like the 'converter' chips, BUT does send a modified signal to the ECU, and probably the power steering too?

If this was the case,then assuming the box ain't knackered, I would think the red-with-white-stripe cable is a key problem - as this is the 12v input, and it's cut in half!

Just to clear myself of any liability at this point - I can't recommend that you join that red-with-white-stripe cable and leave all the other wiring in place (as I don't know exactly what that SP1A box is doing) - but if it was my car, thats what I'd be trying lol.

I'm just a bit cautious to recommend anything outright as there are SRS airbag wires in the vicinity too!

If taking the 'safest' route (safest purely because you'll know whats what) - you could still take everything back to 'stock' wiring to see where you are.
But take note of where everything was, because if you encounter a 112mph limiter, that box (if its working) might help you out.
You might be lucky in taking everything back to stock and the clocks may do the limiter work for you.