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Old 7th May 2007, 15:44   #1
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Building a Tachometer for Swift LDi

I long to have a tachometer on my Swift LDi.

I have decent experience in building the electronics to get the numbers on LCD, but is there any point which will give the pulses ?

Vishnu
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Old 7th May 2007, 16:33   #2
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Quote:
Originally Posted by vishnugs View Post
I long to have a tachometer on my Swift LDi.

I have decent experience in building the electronics to get the numbers on LCD, but is there any point which will give the pulses ?

Vishnu
I am not an electronics expert, but do you mean a tranducer point which will give pulses for each rotation of crankshaft?

If yes try somekind of motion sensor, on timing pully of crankshaft(i dont know if swift uses timing chain or belt), whatever may be the case belt or chain, the main crakshaft pully/sporket is the ideal location to indtall sensor.

What kind of sensor?...that you have to find out & tell me what you have used, may be some kind of magnetic counter may serve your purpose for transducer, but i dont have details for commercially available one.

Please do ltell me how you did it?
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Old 7th May 2007, 16:48   #3
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Rather than using a motion sensor, it would be better to measure the spark rate using something like an inductive tap on one of the spark plug cables. This is how most commercial tachometers work AFAIK.
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Old 7th May 2007, 17:08   #4
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Quote:
Originally Posted by ajitkommini View Post
... an inductive tap on one of the spark plug cables. ...
Err, ajit. Diesels don't have spark plugs or their attendant cables.
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Old 7th May 2007, 17:18   #5
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Right :-) sorry - not enough coffee in blood stream i guess
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Old 7th May 2007, 17:23   #6
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Buy the Instrument cluster from the VDi. Take yours out. Fit that in. There should already be the necessary hook up for the tacho signal somewhere back there. There ya go. A stock looking instrument cluster.

Technically though I don't think this could be legal as you are essentially "clocking" you car, because your ODO will start from 0km again.

That's the basic. Maybe someone else with a better knowledge of the Swift electrics can assist you further.

Ofcourse, if you want to go the RICE way with a huge tacho that blocks 1/4 of the windscreen, thats possible too.
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Old 7th May 2007, 17:58   #7
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Tampering with the vehile in this fashion may invite a termination of warranty. So ask your dealer to do this work for you. That will save you from loosing warranty.
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Old 7th May 2007, 19:23   #8
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Tap the RPM signal fromthe ECU. You will need a wiring diagram of the ecu for this though to verify pin number.
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Old 7th May 2007, 19:26   #9
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Quote:
Originally Posted by vishnugs View Post
I long to have a tachometer on my Swift.
Buy an aftermarket autoguage or autometer tacho. Various sizes and designs are available.
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Old 7th May 2007, 19:39   #10
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In the days of the pre ECU diesels, a waveform was picked up from the alternator, waveshaped, scaled and fed to the tachometer.

Ram Rao
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