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Adjusting a VDO tachometer


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Hello all,

I thought Id post this up. I have recently fitted a VDO tachometer to my 90 tdi and it seems to read very low. Its fed off the W terminal on the back of the alternator. Is there any adjustment on them as at idle it sits at about 500 rpm and flat out is only about 3000rpm.

Any thoughts would be greatly apreciated!

H

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If it's the same as mine, the adjustment process was fully described in the fitting instructions.

There are three DIP switches and a fine-tune pot on the side of the unit. the DIP switches set the rough range and the pot is for fine adjustment.

Edit: D'oh, Ralph beat me to it. :)

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Do you mean that there was adjustment on the back or actually behind the cover as all thats on mine is the 3 connectors on the back, and 3 screws which I assume are for holding the body on.

H

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What is the tacho in? a single enclosure by the sounds if it?

if you've got the actual tacho in your hands, you don't need to remove any cover at all to find the switches, unless you have the wrong unit.

though I'd expect a petrol tacho to still have dip switches to select the number of cylinders.

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I'll go and take it out of the dash and take a piccy. It definately works on the feed from the alternator so thats what i was puzzled by......

H

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I have no idea if its a td5 one tbh......I just bought it at a boat jumble a few months ago. Ive just taken the screws out and they seem to just hold the inner assembly......hmmmmm

H

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Totally different to mine [which is the 50th anniversary V8 version]

a Tdi should rev to 3850rpm with no load on, i.e. not moving the vehicle just revving from tickover while stationary. Bosch call it the 'flight speed'

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Mines the same with no adjustment facility. Mine however sits at a tad below 750 at tick over. Can you get to 3000 in a tdi ?

Mo

Certainly. 200TDIs governors are at 3750. They should rev and power freely up to there. 3000 rpm is 72 mph in a normal stock TDI in 5th gear.

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Aye, well flat out in second with lots of black smoke out the back is 3k on this one. As i paid all of £15 for it, i think that I'll just use it and add it up in my head.

Many thanks for your thoughts though.....

H

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AUTOGAUGE 52mm DIESEL TACHO + FITTING KIT+ POD Item number: 360062318193

see ebay , item number shown above .

i have one on my 300tdi fed from alternator W terminal .

0-6000rpm scale

easy fitment, easy to synchronise and adjust with screwdriver via one single trimmer pot in back of unit .

can set revs infinitely to suit any diesel engine that has a w terminal on alternator .

why pay silly money for a vdo gauge when you can get all you need in this one above, this even comes with a 2" mounting pod included in the price .

Aye, well flat out in second with lots of black smoke out the back is 3k on this one. As i paid all of £15 for it, i think that I'll just use it and add it up in my head.

Many thanks for your thoughts though.....

H

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why pay silly money for a vdo gauge when you can get all you need in this one above, this even comes with a 2" mounting pod included in the price .

Well let's see...

1) That one costs more than a VDO.

2) The colour scheme looks nothing like the stock gauges.

3) 6000 rpm is much higher than needed.

a 4000 rpm VDO Vision is perfect.

maingauges.jpg

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