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1980 230 coupe
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Can anyone help me on this one, i have fitted the rev counter and the economy guage from a newer 123 series model to my 1980 230 coupe. Ive got the rev counter to work that was very easy but i have no idea of how to wire the economy guage. On the back of the speedo there is a little black box with two electricle connections ( marked M/B, 004 542 6517, VDO, 88 374 007)Has this anything to do with the guage, if so what doose it cnnect to and if not what is it for? I did wonder if it connected to the rev counter but did'nt want to try it incase i wrecked something Any help would be very much appreciated







[?][?][?]
 

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moccomerc - 5/16/2005 4:45 PM
Can anyone help me on this one, i have fitted the rev counter and the economy guage from a newer 123 series model to my 1980 230 coupe. Ive got the rev counter to work that was very easy but i have no idea of how to wire the economy guage. [?][?][?]
That economy gauge is connected to a vacuum hose. Two things you will need are: a T/Y connector and a long vacuum plastic line/hose. Just attach a T or Y type connector in-between to an existing vacuum line in your engine area and attach the long hose to the other connector and run it through the firewall rubber grommet next to the booster pump and up into the back of the instrument cluster - and then plug that end of the vacuum line into the economy gauge male fitting securely. Once you start the car, vacuum pressure builds up, and you should see it fluctuate back and forth depending on how much throttle/gas you give. It's quite simple - very easy project. Just make sure everything is secure in order to prevent leaks. TAKE YOUR TIME. I installed one on my car with good results. Enjoy!
 

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W-1-2-3 Go!
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Alfie, thanks! I was wondering how to install one (one of my "plans" when I get to it heh[:D])

By any chance, do you know if the gas-tachometer (with red zone) is compatible with the diesel tacho?
 

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karugs - 5/16/2005 6:27 PM

By any chance, do you know if the gas-tachometer (with red zone) is compatible with the diesel tacho?
The gas tacho is NOT compatible with diesel cars...totally different internal mechanisms inside. The diesel tachos from 84-85 have built in amplifiers inside the tach unit. The 82-83 turbodiesels require that tall tach amplifier 2" canister seen on the driver-side fender well. The W123 wiring diagrams for each year clearly differentiates between the two.

Here is the econo-gauge. I have it on my wagon now - that's how I know how to install it!. Works great! It's harder to find here in the US since the W123 economy meter gauge came only on Euro-spec petrol versions... but it works in diesel cars - no problem at all - all it is is just a simple extra vacuum hookup:

 

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thebenzbar - 5/16/2005 8:07 PM

karugs - 5/16/2005 6:27 PM

By any chance, do you know if the gas-tachometer (with red zone) is compatible with the diesel tacho?
The gas tacho is NOT compatible with diesel cars...totally different internal mechanisms inside. The diesel tachos from 84-85 have built in amplifiers inside the tach unit. The 82-83 turbodiesels require that tall tach amplifier 2" canister seen on the driver-side fender well. The W123 wiring diagrams for each year clearly differentiates between the two.

Here is the econo-gauge. I have it on my wagon now - that's how I know how to install it!. Works great! It's harder to find here in the US since the W123 economy meter gauge came only on Euro-spec petrol versions... but it works in diesel cars - no problem at all - all it is is just a simple extra vacuum hookup:

Vacuum gauge on a diesel? Why?
 

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MB-Owner-in-ind - 5/16/2005 10:11 PM

Vacuum gauge on a diesel? Why?
My preference...so why not?? I was actually saving it for a 280CE I'm searching for, so in the meantime I needed to see if it works, and so it does! Anyways, it's so easy to swap out in no time... [:D]
 

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1980 230 coupe
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Discussion Starter #7
Many thanks for your help, i will connect it up soon as i have the necessary parts' time and it stops raining. I fitted the rev counter a while ago and dont remember there being any connection for a vacume hose but im sure there must be. ( tempted to steele the connectios and vacume pipe of from a fish tank as its available) so what is the electricle connection on the back of the speedo for, im not using that speedo so it dose'nt matter but i would like to know[[?] Happy Motoring
 

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moccomerc - 5/17/2005 6:11 AM

Many thanks for your help, i will connect it up soon as i have the necessary parts' time and it stops raining.... so what is the electricle connection on the back of the speedo for, im not using that speedo so it dose'nt matter but i would like to know[[?] Happy Motoring
That connector (if it's the black module w/ 2 male prongs) is your RPM sending unit for the cruise control module. If you have cruise control - then the plug w/ harness attaches to the back of the speedo via this connection. Check the online wiring diagrams - it's all laid out there quite clearly for your installation. [:)]
 

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1980 230 coupe
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Discussion Starter #9
[:)]Thanks for that, would love to have cruise control, had it in my 1982 200 it will be something to work on. Anyway the economy guage is now fully funtional, thanks to the local pet shop
Just got this weeks free adds (Weekly newspaper covering 100mile radius)There' a 280ce coupe advertised as being very rare because its diesel mmmmm
going to have to give it a ring
 

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1980 230 coupe
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Discussion Starter #10
[:)]Thanks for that, would love to have cruise control, had it in my 1982 200 it will be something to work on. Anyway the economy guage is now fully funtional, thanks to the local pet shop
Just got this weeks free adds (Weekly newspaper covering 100mile radius)There' a 280ce coupe advertised as being very rare because its diesel mmmmm
going to have to give it a ring
 

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