82 300SD tachometer - PeachParts Mercedes-Benz Forum

shantibala · #1 07-16-2006, 10:33 PM

my uncle just came over with his 82 300SD turbo and the problem we have is that the tachometer revs up when he pushes the gas but when he lets the gas go it drops to 0 even tho the engine is still running perfectly what could the problem be? the ac clutch isnt working could this cause the problem?

JamesDean · #2 07-16-2006, 10:40 PM

does the tach come back up if he pressed the gas again?

Check the Tach Amplifer...Located on the driver's side fender. It looks like this

[IMG]http://www.***************/secure/PartImages/0015455932.jpg[/IMG]

Only its actually screwed into a socket.

Those tend to go on the diesels. I replaced mine. Working fine ever since.

Kris

shantibala · #3 07-16-2006, 11:01 PM

he said he had changed that just recently with the specific number however he got the part from a junk yard. Should he go buy a brand new one or what else could be causing the problem??

JamesDean · #4 07-16-2006, 11:37 PM

my guess would be that that part is the problem....before you go spring for a new part try this:

you see how that part is like two pieces? pull the smaller piece out of the larger . and take a cigarette filter or a small piece of cardboard and wedge it up in the larger one. then take the smaller piece and put it back into the larger to reassemble it. the carboard/cig filter will pressdown on the pins. Try this with both the one from the yard and the old if u have it. If tach operations return to normal i would replace it with a new one. Or u could leave the "fixed" one until it doenst work and then buy a new one.

just my 2 cents

kris