My tach goes nuts most of the time now.
Some days it tells me the RPM and sometimes it bounces
like it's dancing. Some days it just rests and tells me nothing.

What do ya think is the fix for this?
Thanks!

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Ginny in Denver-ish
78 300SD, 265K (mine)

Try the cigarette butt fix. (covered in earlier threads, can find with search function) I did this with mine and it still doesn't work all the time, but it's on like 75% of the time instead of 10% like before. Best of all, it's free and easy. This is assuming the tach amp setup on the W116 is the same/similar to the W123.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

Cool!
Thanks. I'll try this in the AM. I have a neighbor who smokes outside
on her porch every morning. I'm sure she'll give me a used butt.

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Ginny in Denver-ish
78 300SD, 265K (mine)

the cigarette butt worked for me... the hardest part is getting the thing out of the cap that you take off of the tach amp sender

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-Trevor

OBK #12
1980 300SD 333,XXX miles - Totaled
1986 Mazda RX-7 212,XXX miles - impounded and auctioned off
2005 Jeep Liberty CRD Limited 33,000- SEGR, Provent, Fumoto

I did something similar, worked for a while.

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83 SD

84 CD

Ginny-

You need to line up some pick-n-pulls in your area for bits and pieces like this. The cigarette but trick may work, may not. You will probably have to find another tach amp eventually.

Rick

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

After trying putting stuff in the cap and having it work for a few days and then going out again I took the socket that mounts to the fender off and crimped the sleeves that the amp plugs into just a little. This is the best, longest lasting fix that I have come up with and its been working for 4 weeks now. The problem with these is after years the sleeves get loose and no longer make good contact and when you put stuff in the cap it just pushes the sleeves farther out and makes them even looser.

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1983 300SD
200000miles