Speedo Correction

[Banjo]

I've just got around to cutting up the AE101 SVS speed sensor I bought on ebay, so that it fits the KE70 5 speed gearbox speedo drive. I'm now ready to test it, but can't find anywhere on the net, what the connections are for this unit.

 

They will be 12V, GND, & O/P, but don't know which is which. No markings on the plastic socket.

 

 

Can anyone help ?

 

Cheers Banjo

Edited August 12, 2016 by Banjo

[Banjo]

OK, finally got it sorted. Found a website that shows how to test a Toyota SVS speed sensor off the car, with a wring diagram.

 

The pin numbers on the AE101 sensor socket are as follows . . .

 

 

Here are the testing connections.

 

 

Pin 1 goes to +12V

 

Pin 2 goes to Gnd

 

Pin 3 is the output voltage pulses.

 

I hooked it all up on the bench, and at first it did not produce any pulses. I then realised it was probably an open collector output, so I hooked a 10K ohm resistor between O/P (pin3), and +12V, and it worked fine.

 

I then marked the shaft with a bit of white-out, & turned the spindle by hand, several times, and confirmed that the SVS speed sensor produces four (4) pulses per revolution.

 

Trust that helps some else who may want to do this mod on their KE Corolla.

 

When I find an electronic pulse input speedo dial from another car, that will neatly fit my KE30 dash, I'll post my findings here. If anyone knows of one that is a close fit, please post here. The KE30 speedo dash face is 90mm in dia.

 

I guess, I will also have to insert a Jaycar speedo correction box in between the SVS sensor & the electronic speedo.

 

http://www.jaycar.co...-manualMain.pdf

 

Then goodbye speedo cable. That will make it a little bit cleaner under the bonnet.

 

Cheers Banjo

Edited August 12, 2016 by Banjo

[filfrederick]

Most modern speedometers use the magnetic eddy-current type of gauge, it can be internally adjusted by moving the eccentric spacer inside the rotary magnet to change the interference of the magnetic field relevant to the poles. I have not done it on a ke instrument cluster before but all use the same principal so with a bit of time they can be calibrated within a few % of actual speed. it is a fiddly job that requires pulling the whole speedometer to bits but not particularly hard.

[Banjo]

Fiddy job me thinks ! I just had a look at a KE speedo, and I can imagine after each adjustment, you would have to completely reassemble it, to test its accuracy. How many times did you pull it to bits & put it back together, before you were happy with the result ?

 

Cheers Banjo

[filfrederick]

Yeah it can be a time consuming job,

With the ones that I do a lot I test the car with a gps to see what the speedo reads when the gps is at exactly 100kph for example then I pull the speedo from the car and run in with my lathe with a digital readout of the rpm to get the speedo to read whatever it did on the test run and record the lathe rpm. then the eccentric in the speedo is adjusted until it reads 100 at that same input rpm. Like I said I have not done it on a Ke speedo, they may not have a method for adjustment without changing the strength of the magnetic field. (which is a real pain to get anywhere near) 80s toyotas are not renown for their instrumentation quality.

 

With the ones that I do a lot I have made a graph of the position of the eccentric spacer and how much it will change the result. it usually only takes one or two attempts to get them spot on.

 

hope that helps, but it probably doesn't haha

-Phil

[Banjo]

Hi Phil,

That was very helpful, thank you. I read your post twice, & then went Wow ! I've always known basically how a a speedo works, but never taken a great deal of interest, but after reading your post, I grabbed the KE speedo, and took it off to the workshop and held it in the vice. I then put a pencil in my variable speed hand drill, & with the drill in reverse, drove the speedo with the tapered part of the pencil pressing up against the driven part of the speedo, where the cable fits. You can clearly see how it works, with the mild steel drum, pulling the magnet section fitted to the needle, until the hair spring reaction balances out, & you get a relatively stable reading.

 

http://www.howacarwo...eedometer-works

 

However, it was obvious, that any minor adjustment you do to the eccentric magnet position, to correct the speedo readings klm/hr, has no effect on the odometer & trip meter, as these mechanical plastic geared driven chains, are directly driven by the input shaft & cable, and not affected by any adjustment you make to the klm/hr reading.

 

My need to correct the speedo is because I have changed diff ratio & wheel & tyre sizes. Mine is out about 8-10% approximately.

 

My conclusion is, if I stayed with a mechanical speedo, and had it adjusted some how, as you describe, that my klms travelled & trip meter totals will still be out by 8-10%.

 

To many people, this may not matter. However, there are many girls & guys on this forum, who like me, probably quickly check the trip meter & zero it, each time we fill the tank up with petrol, to see what sort of mileage we are getting. Each of us have a figure for our car for say city or country driving, for a full tank. If it then changes suddenly, it is a good indication that something is wrong, or my wife has been driving it & hammering it ! Ha Ha. :lol: :lol:

 

Correct me if I'm wrong, but in the case of the electronic speedo, I believe the odometer & trip meter are are LCD displays, & would therefore coincide with the speedo reading if the calculation was done, over time between the two readings.

 

I think I will stick with my decision to go electronic pulse speedo. I've sorted out the sensor; just need to find an electronic speedo mechanism that will fit the KE30 dash cluster.

 

Anyone in Brisbane got a AE101 electronic dash cluster or speedo bit, that I can borrow or buy, to try it for size ?

 

Thanks Phil, great insight !

 

Cheers Banjo

Edited August 16, 2016 by Banjo

[filfrederick]

Yes, the odometer/ trip can only be changed by gearing as you stated as it simply counts the number of rotations.

 

glad I could be of some use at least.

If you really want to blow your mind, take a look at the old smiths/jaeger chronometric speedo/rev counter mechanisms. they are amazing. my favorite mechanical device at the moment, has just overtaken the magneto to the top spot.

 

http://www.wdbsa.nl/Jaeger-Chronometric-Overhaul.pdf

 

-Have fun - Phil

[Hiro Protagonist]

Correct me if I'm wrong, but in the case of the electronic speedo, I believe the odometer & trip meter are are LCD displays, & would therefore coincide with the speedo reading if the calculation was done, over time between the two readings.

 

AE101/2s still ran analogue odometer/tripmeters

[Banjo]

Hi Ian,

Thanks ! Yes, I did notice the analogue trip & odometer dials on a couple of pictures I gleaned on the web.

 

 

Must get down to the wreckers soon & have a hunt around.

 

Cheers Banjo

[Hiro Protagonist]

Edited August 18, 2016 by Hiro Protagonist

[Banjo]

What was the first model Corolla in Australia, that was supplied/fitted with an electronic speedo, with a pulse VSS fitted to the gearbox, rather than a cable drive ?

 

Cheers Banjo

[Hiro Protagonist]

What was the first model Corolla in Australia, that was supplied/fitted with an electronic speedo, with a pulse VSS fitted to the gearbox, rather than a cable drive ?

 

Cheers Banjo

 

AE92s definitely still had a mechanical speedo cable (at least on the 4AGE models) so probably is the 101/102s. They didn't start having digital odo/trips until the ZZE series though

Edited August 21, 2016 by Hiro Protagonist