I am about to buy a 1983 300SD, (my second), still don't have the first one going, but really bought it for parts anyway. The 300 I have picked out is nice in and out, new AC and runs well. Only thing wrong is the RPM gauge doesn't work or works sometimes. What am I looking at. I did a search and didn't really see anything.

Thanks and I am living vicariously reading your posts everyday you are a great group of men and I am so pleased to have found you all.

I'm pleased to have been found, but what will Jentay and Webwench think?
-Joe

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

LOL......... Ive long since quit caring what anyone thinks.......what was it someone said, its not a good day unless you get odd looks from the neighbors!

Hi, Ken.

There are some great posts that detail the issues that may be involved and how to deal with them. Try searching using the term 'tachometer' instead of 'RPM gauge' and you should find more relevant posts.

Best of luck!

OK

I went and put in tachometer and got 15 posts, I read all of every one of them and one might apply in reference to a speedometer not being grounded.

Is there anything else I might look at or consider in trying to repair my broken Tach?

Thanks

The tach amplifyer or (amp) is also a good topic to search, as it has been the cause of a lot of grief. However it is also an item that has proven to be fairly easy to apply a relatively inexpensive fix which restores tach operation.

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150

Ken,

I had similiar problems with 85 300D. There is an amplifier under the hood on the drivers side fender near the front . It is a black round screw cap. I think mine says VDO on it with maybe a symbol of a transistor. If you unscrew the cap you will see the plug in your hand and the socket on the bottom. The amplifier is the top part. For some reason the plug doesn't always make good contact. I read someone elses post which suggested carefully prying out the plug from the top cap. You will notice that this plug has room to slide in the top cap. Pry it out and place couple of pieces of cardboard behind it. This will push it into the socket with a little more force. It tried this and it worked for a year. I am back to having it work 50% of the time.

TimK

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85' MB 300D Turbo
85' GMC Suburban 6.5L Diesel Turbo
2000 VW Beetle 1.9L TDI Diesel Turbo
67' Land Rover 2.5L Diesel - No turbo

So what do you do when it's so cold out your fuel gels? Smear some on toast and have another cup of coffee until it warms up outside.

TimK has got it right, only I used a cigarette butt behind the amp (you'd be amazed how easy it is to find a cigarette butt anywhere on earth).

Also, a bit of dielectric grease on the contacts is a good idea. I did both of these to mine and it's worked perfectly for months.

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1984 300Sd 210k

Former cars:
1984 300D 445k (!!) (Strider) Original (and not rebuilt) engine and transmission. Currently running on V80 ( 80% vegetable oil, 20% petroleum products). Actually not, taking a WVO break.
1993 300d 2.5 275k. Current 120/day commuter
1981 300SD 188k (Hans) Killed by a deer

Hi and Thanks !
I've been reading the posts about tachs. I seem to have a different kind on my 84 300 D . It's not as tall as the one in my 83 TD wagon. No contacts in the cap ......just a plastic cover . Anyone know about fixing thesekind ? It just quit working 3 days ago for no apparent reason. Although it was after the voltage regulator was replaced at a shop.
Thanks

Follow the grey wire from the amp to the tach sensor. The tolerances between the sensor tip and the post coming from the balancer is .008.

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BENZ THERE DONE THAThttp://www.peachparts.com/shopforum/...c/progress.gif
15 VW Passat TDI
00 E420
98 E300 DT
97 E420 Donor Car - NEED PARTS? PM ME!
97 S500
97 E300D
86 Holden Jackaroo Turbo D
86 300SDL
(o\|/o)