Quote:
Originally Posted by larrylarkin
SORRY ABOUT NOT POSTING WHAT AUTOMOBILE THE TACH QUIT WORKING ON. IT IS A 1995 MERCEDES 300E DIESEL. I WOULD LIKE TO KNOW HOW TO TROUBLESHOOT IF THE PROBLEM IS WITH THE WIRING OR THE SENSOR ITSELF? SOMETIMES THE TACH WILL WORK IF THE ENGINE IS RIVING UP ABOUT 2500-3000 RPM THEN IMMEDIATELY IT DROPS BACK TO ZERO. I HAVE CHECKED THE FUSES AND FOUND NO TROUBLE WITH THEM. IN FACT I DO NOT THINK THE TACH IS FUSED, IF SO, I CANNOT FIND IT.
THANKS!
LARRY L L
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The tach gets its signal from an electronics box that operates the EGR system (and other things). This box is powered through an over-voltage protection relay, which has a ten-amp fuse. While you are checking for bad contacts and connectors, check the OVP (probably in a little compartment behind the battery).
Since you have a diesel, you may wish to post in the Diesel Discussion -- the diesel experts hang out there. Your 1995 is the last year for the W124 chassis and the first year for the OM606NA engine so it is somewhat unique.
Please don't write in capital letters; it is the Internet equivalent of shouting and some people consider it rude and won't help you with your problem.
Jeremy
__________________
"Buster" in the '95
Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
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"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970
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