So far I have learned that tachs for 91,92,93 do not have amplifiers located on drivers front fender. No one even at M/B dealers know if an amplifier is needed. There was a suggestion on this forum that a type of amp is built into the "EGR MODULE" on 1985 models and later. I cannot verify that fact or where that module is in the 1992 124 body 300D.

Bottom line is that the rpm pickup cable is good, the flywheel magnet is there, the OVP fuses are good, gas model tachs were connected and worked but gave false readings (pegged the dial).

That would suggest the problem might be in the diesel tach itself...like maybe a capacitor is bad (or other electronic component)....or the thingy in th egr is bad....

There are other members who have same problem as me....ANY IDEAS ?