Hello all,

Need you expert assistance, car is a 83 300SD, problem is my tack does not register a thing. Had a 300TD for parts and used the tack from it as a test unit, still nada. Read somewhere there is a round RPM sensor (on left firewall near break boster above teh injection pump) which may be my culprit, but how do these beauties sense crank position and process signal to let the tack (which appears to be a dial method similar to the old VOM) get voltage to move upward as the revolutions increase? Also to the kind helping soul(s) would you provide electrical diags for me to troubleshoot the system?

Thanks for your help.

Adriano

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Adriano

83 300SD 500,300 miles (Well seasoned work horse AKA "Put Put")
93 300D 245,000 miles (Moms Baby AKA "Sweat Pea")
87 300D 185,000 miles (Life giver, aka parts car for my 300SD)

Look on passenger side (inside) behind kick plate

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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)

Are you sure its your sensor? From what I've read here its more likely to be the amp. Do a search on 'tach amp'. Or, just try the cigarette butt test: unscrew top, pull unit from inside top, insert a couple of butts and reassemble. Works for awhile. Look on the drivers side fender for a little cylinder with 'VDO' on the top.

Good luck!

Scot

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"Be kind to thy ass for it bears thee" -John Muir

83 300TD & 84 300D

Yeah i have the same problem it is the amp. I just unsrew it pack it with cotton and marculiosly it works again for a while. Gets a little annoying because it seems like i am doing it every week. oh well.

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81' 300SD AKA "Big Helga"
84' 300D Euro spec (Veronika)
85' 300D NonCalifornia (Heidi)

"We shall not fail or falter; we shall not weaken or tire...Give us the tools and we will finish the job."
-Winston Churchill, 1941

"I'll have a Chinchilla!"

I have a non-functional W116 tach. Does this hold for my tach too?

At first I thought you guy's were pulling my leg, but 2 posts with the "butt" cotton reply. What exactly are you suggesting, there is a cilindrical device on left fender firewall (dark charcol color almost black) which contains another device which has 4 contact )pins) protruding off the bottom.
Are you suggesting I take this unit apart and fill it's body with "cotton"? What about the circuitry inside?

Thanks for the input

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Adriano

83 300SD 500,300 miles (Well seasoned work horse AKA "Put Put")
93 300D 245,000 miles (Moms Baby AKA "Sweat Pea")
87 300D 185,000 miles (Life giver, aka parts car for my 300SD)