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1985 380SE
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1,939 Posts
Discussion Starter #1
Aside from the obvious visual differences of the '82 tachometer and the '83+ tachometer there is another difference. On the '82 tach there are only 2 pins (1 for signal, 1 for power). On the '83+ tach there are 3 pins. For a while now I've been wanting to install a tach in my 1982 240D standard shift. On a normal dry day I can hear the engine just fine but in heavy rain when the water makes a lot of noise in the wheel wells or in traffic I have a more difficult time hearing the engine this causing poor shifts here and there. Using the EGR computer to power the tach will be my best option to have a working tach. But here's the question: Will I be able to use an '83+ (3-pin) tach powered by the EGR computer on my 240D? If so, I'll go ahead and stop looking for the 2-pin tach and get the more available 3-pin one.

Thanks in advance?
 

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2013 MINI Copper S Clubman, '84 300CD-weekend car
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10,152 Posts
I would think a three pin unit will work, do you have the necessary wiring harness?

I say a three pronger as the older style two prong takes the signal from the front crank sensor.
 

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´85 300D Estate, Unimog 411
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115 Posts
Aside from the obvious visual differences of the '82 tachometer and the '83+ tachometer there is another difference. On the '82 tach there are only 2 pins (1 for signal, 1 for power). On the '83+ tach there are 3 pins. For a while now I've been wanting to install a tach in my 1982 240D standard shift. On a normal dry day I can hear the engine just fine but in heavy rain when the water makes a lot of noise in the wheel wells or in traffic I have a more difficult time hearing the engine this causing poor shifts here and there. Using the EGR computer to power the tach will be my best option to have a working tach. But here's the question: Will I be able to use an '83+ (3-pin) tach powered by the EGR computer on my 240D? If so, I'll go ahead and stop looking for the 2-pin tach and get the more available 3-pin one.

Thanks in advance?
sorry for my question but, what is a EGR COMPUTER??? Is it possible to just attach your tachometer to the alternator??
 

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1985 380SE
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1,939 Posts
Discussion Starter #4
^ The EGR computer is stuffed under the dash somewhere on the passenger side in the 240D. Only '81+ models will have it though.
 

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money pits of various forms
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5,885 Posts
I cant remember which but either the 2 or 3 prong picks up on the flywheel and that is 84 and up not 83 (unless maybe the 83 is a cali, my exp with thos is limited). The pick up on the fly wheel requires the proper intermediary plate, or the story as to why my tach does not work.
 
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