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84' 300D, 02' C320 wagon
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Discussion Starter #1
Just purchased my first 300D turbo on Sunday. As soon as the rain stops I will clean it up and post some pics in the new member and photo forum. I am also waiting for the Haynes manual to come in because I most certainly will need it.

The reason for my post is the previous owner had a new.......ish motor installed. Apparently the reason the tach does not work any longer is due to a compatibility issue. Something to do with being a magnet versus direct link. The place that replaced it told him it would be easier to install a aftermarket tach. :confused:

Well I want to fix it so here I am. Actually the odometer and trip are also not functioning. Since this will be a driver I wonder if I can replace the whole instrument panel for the correct year/type motor?

Thank you


Wadesdad1 in Sacramento, CA
 

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2013 MINI Copper S Clubman, '84 300CD-weekend car
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The 84's and 85's use a lead off of the transmission, earlier models used the magnetic pick up.

What year engine is in it now?
 

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84' 300D, 02' C320 wagon
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Discussion Starter #3
Ran out and took a peek at the block. It's hard to see but the last two numbers are very clear 82. Also the speedo is working fine. Thank you
 

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2013 MINI Copper S Clubman, '84 300CD-weekend car
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I would think if the transmission is still the 84 unit, the tach should work.

There is an OVP relay with a red spade fuse, located near/beside the glove box. If you can find the relay, a tall silver box, check the fuse.
 

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84' 300D, 02' C320 wagon
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Discussion Starter #5
Checking the fuse seems easy enough. Makes sense if the transmission is an 84. I might have to wait for my manual to get here. This may take some time.
 

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Late 84/85 moved/duplicated the tach sensor to the rear intermediate flange of the engine, right next to the transmission. The flange is removable and could have been swapped over (when the transmission was out), if this was an older style engine being put into a newer car. If it's a newer style engine put in an older car, the newer style engine has both sensors, front and rear. In that case there shouldn't be much of a problem.

Some 84s are new style, some are old style.

Look into the subject of the tach amp, it's what the older cars used. There's info out there on how to tell what kind of car you have (whether you have a tach amp or just an empty capped socket on your inner fender).
 

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84' 300D, 02' C320 wagon
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Discussion Starter #7
So can we talk worse case scenario? It's an 82 motor, late 84 trans, and fuse is fine. Am I looking at a engine removal or mix the gauges on the panel to accommodate appropriate years?
 

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84' 300D, 02' C320 wagon
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Discussion Starter #9 (Edited)
1984. So I am trying to think this through..........if the fuse is good I have a big problem. I will have no means of connecting the tach. I have an 82 engine in an 84 with a tach that was originally hooked to the rear flange. Since there is no flange that is not an option. Since the transmission is a late 84 it does not have the part to connect to.

Can the part be added to the transmission without removing it from the car?:(
 

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Figure out which 84 it is, the early 84 hooked to the front. You can't swap the flange without removing the trans. So if you have a later 84 I would get an early style tach amp and an early style instrument cluster (just the tach part), plug the amp into the empty socket, and then string up some wiring from the amp to the instrument cluster.
 

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84' 300D, 02' C320 wagon
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Discussion Starter #11
Is this what I am looking for? Sorry still waiting for manual......it's in the mail.

http://i208.photobucket.com/albums/bb164/jeffhenderson9/ebay 2/DSCF0271.jpg

So this will plug into the spot even though it does not belong to that year? It will have the necessary power and signal? Thank you this seems like the practical solution if it's no the fuse and is a late 84'. Now finding the tach........
 

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2013 MINI Copper S Clubman, '84 300CD-weekend car
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That should work, you'll need the wiring harness from the amp socket to the tach itself and you'll be set.
 
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