I predict a Riot
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| posted on 17/7/12 at 08:18 PM |
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Under reading speedo
I am trying to set up my Isspro electronic speedometer to read correctly with the standard sender fitted to the Ford IB5 gearbox.
I can get it nearly there but it still under reads by about 5mph and that is with the lowest calibration number Isspro list.
Can anyone help me out with these questions:-
I know that the sender is a hall effect type with a rotating magnet and a fixed sensing coil, it operates with 12volts but what is the nature of the
output signal?
How many pulses does it generate per revolution of the wheel? I am using 15" wheels the same as the Ford Puma the gearbox comes from.
Are there any readily available electronic multiplying units? Or am I better ditching the sender and glueing magnets to the drive shaft?
Thanks for any help you can give. IVA on the 25th so getting tight for time.
"Honesty is a very expensive gift. Do not expect it from cheap people ". Warren Buffet on Expectation
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bi22le
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| posted on 17/7/12 at 08:44 PM |
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Why not glue a second magnet on and them half the signal speed until its accurate.
Double the magenets will double the refresh rate anyways so it will make more accurate under hard acc \ dec.
HTH
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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Westy1994
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| posted on 17/7/12 at 08:52 PM |
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Been trying to search for you very very little luck. I can't seem to find any data sheets on your gearbox sensor at all.
I did read one post on a Ford forum that read
" 'SpeedoHealer' is a microprocessor unit that changes the frequency of the signal from the gearbox vehicle speed sensor (VSS).
Originally developed for tyre/gear changes on Bikes but very useful in cars.
http://www.bikersdiscountstore.co.uk...r-v4-pd-18.php
The MTX/IB5 gearboxes have a nylon/steel disc replacing the speedo gear on the diff. The MT285 (ST170) box was design with a VSS, so the sensor just
reads the FD gear. As a result the ST170 outputs about 3.5 times more pulses per driveshaft revolution. Real pain if swapping boxes.
On the Mk1 Focus, the VSS sends its signal only to the PCM/ECU. That is then programmed to send out, according to wheel/tyre (and also the gearbox) a
legacy pulse signal (for radio and cruise control) and on the digital highway. The speedo can display speed (and other measurements, on the Odometer
when in diagnostic mode.
There should be detailed topics on diagnostic mode, but basiclly, hold down the odometer button whilst starting the engine. All lights come on,
needles swing, then use button to scroll through various parameters."
But that unit is not cheap at £80 odd
Seems most aftermarket gauges do not allow you to use the OE sensor, as they want you to spend more money and buy their own instead, it would be very
easy to pre-program a gauge with the most popular sensor's outputs, but they don't.
I would use the magnets as already suggested, or contact Isspro directly and find out what you need to get it to work.
Rich
[Edited on 17/7/12 by Westy1994]
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owelly
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| posted on 17/7/12 at 09:02 PM |
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Probably no help to you but.....
It seems all Fords use 8000 pulses per mile. If you work out that there are 1609344 millimetres in a mile, you can work out how many times your final
drive rotates with your sized tyre.
As I said, it may be of no help whatsoever...
ETA. This guy does converters....
http://www.picbits.co.uk/catalog/product_info.php/products_id/168
[Edited on 17/7/12 by owelly]
[Edited on 17/7/12 by owelly]
http://www.ppcmag.co.uk
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I predict a Riot
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| posted on 17/7/12 at 09:18 PM |
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Thanks everyone that's all really usefull info' as always.
I can't add any more magnets to the existing sensor as it's a rotating circular magnet inside the sensor coil, therefore no room.
I asked Isspro and their sensor was over £100!
You have given me an idea though - I'm using the output directly from the sensor into the Ford MUFF ECU, I had assumed that the ECU output to
the original instrument cluster would be incompatible with the Isspro speedo but I will hot wire it in tomorrow and give it a go.
Thanks for the ideas - much appreciated.
Adrian
"Honesty is a very expensive gift. Do not expect it from cheap people ". Warren Buffet on Expectation
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Krash67
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| posted on 17/7/12 at 09:29 PM |
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I know that the sender is a hall effect type with a rotating magnet and a fixed sensing coil, it operates with 12volts but what is the nature of the
output signal?
All the sensor is doing is generating a micro voltage between the sender and the reciever every time the magnet passes the head unit. Creating a
simple frequency signal. If you have a really good DVM ( digital voltmeter) and set it to register the lowest/ highest readings you will pick the
voltage ( amplitude) of the pulse. What is critical is the gap between the sender and the magnet. Too bigger gap will create issues in pickup and loss
of detection of the passing magnet. To little gap..... The magnet wipe the end off the head unit!!! Lol.?.....also long term is iron particles
sticking/fouling the magent.
However you make reference it operates on 12volts. Is this the supply voltage to the receiver or on the line to the head/pick up?
If your not fast..........your last!!!
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I predict a Riot
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| posted on 17/7/12 at 09:47 PM |
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The sender has three wires - +12volt, Gnd and a signal direct to the ECU.
"Honesty is a very expensive gift. Do not expect it from cheap people ". Warren Buffet on Expectation
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jollygreengiant
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| posted on 17/7/12 at 10:06 PM |
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another alternative, do as I did, work out the correct rolling radius of tyre for your set up and fit as reuired. When SVA'd my speedo was 100%
accurate with no electricery. If you speedo is under reading by 5%, then I suspect that you will need to come down by one aspect raio of trye. This
can be checked on the various tyre check web sites available including the one that has been most mentioned on this site.
JMHO
JGG.
Beware of the Goldfish in the tulip mines. The ONLY defence against them is smoking peanut butter sandwiches.
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snowy2
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| posted on 18/7/12 at 08:25 AM |
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look at this site, they have a UK operation, it could be the exact thing your looking for......
It comes in kit form but a build service is available, they are a hobby kit so are very easy to make.
speedo
corrector
this is copied from the New Zeeland wed site but gives a better description of what it does.
Speedo Corrector MkII Kit "Kit Back Catalogue"
Kit Back Catalogue
Please note: This item is only available for purchase on our website. It is not available in stores.
When you modify your gearbox, diff ratio or change to a large circumference tyre, it may result in an inaccurate speedometer. This kit alters the
speedometer signal up or down from 0% to 99% of the original signal. With this improved model, the input setup selection can be automatically selected
and it also features an LED indicator to show when the input signal is being received. Kit supplied with PCB with overlay and all electronic
components.
> Recommended box UB5 use HB-6013
Please note: This item is only available for purchase on our website. It is not available in stores.
[Edited on 18/7/12 by snowy2]
sometimes you are the pigeon, most of the time the statue.
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