Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes ShopForum > Technical Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 11-27-2010, 12:48 PM
Registered User
 
Join Date: Nov 2010
Posts: 26
Tach not working

I have a 1995 300E diesel and the tach quit working. Just wondering how do I check and see if it is in the wiring harness or the sensor itself. Sometimes it will work when the car is reved up and then it suddenly
goes back to zero. It usually does this when everything is cold. (First started)
Thanks!
Larry L Larkin
Reply With Quote
  #2  
Old 12-04-2010, 01:34 AM
Registered Hack
 
Join Date: Mar 2008
Posts: 4,602
does the 606 use a sensor on the flywheel, or the crank?
Reply With Quote
  #3  
Old 12-04-2010, 01:55 AM
Jeremy5848's Avatar
Registered Biodiesel User
 
Join Date: Mar 2006
Location: Sonoma Wine Country
Posts: 8,390
I think the '95 has an Over-voltage Protection relay like the rest of the W124s so I would check that first. If the tach is not working, the air conditioning and cruise control may also not work. I realize it's the wrong time of year for a/c but you might see if the cruise works. I should know from my own 606 where the tach sensor is but I don't and the car is still at the body shop so I can't go look.
__________________

"Buster" in the '95

Our all-biodiesel family
1995 E300D (W124) . .239,000 miles My car
1996 E300D (W210) . .313,000 miles Wife's car
Santa Rosa population 170,685 (2012)
Total. . . . . . . . . . . . 722,685
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970
Reply With Quote
  #4  
Old 12-04-2010, 09:28 AM
Registered User
 
Join Date: Nov 2010
Posts: 26
Jeremy5848
Thanks for the information. You are correct and I have found the probllem.
It seems to be the connection between the sensor wire and the over-voltage
relay. I bought a new sensor wire but it did not help matters, but when I started to "jiggle" the wires to the over-voltage relay it started to work. Looks as if the over-voltage relay has been replaced at some point because it was not fastened down. I secured it with wire ties and now I think my tach will work. Thanks again!!
Larry Larkin
Reply With Quote
  #5  
Old 12-04-2010, 12:28 PM
JimmyL's Avatar
Rogue T Intolerant!!!
 
Join Date: May 2004
Location: Sunnyvale, Texas (DFW)
Posts: 9,673
My intermittent tach on my '95 was the OVP relay. If yours comes and goes, consider replacing it. Very common......
__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John
Reply With Quote
  #6  
Old 12-04-2010, 01:23 PM
Jeremy5848's Avatar
Registered Biodiesel User
 
Join Date: Mar 2006
Location: Sonoma Wine Country
Posts: 8,390
Jimmy is right. Why OVP fails as much as we seem to read about I do not understand. There's hardly anything in there -- a relay, a Zener diode, and a fuse. If anyone would like to send me their dead OVPs, I will find out what failed. It would be an interesting project and if I can make a repair, the OVP goes back to the donor at no charge. It would be worth it to develop an understanding of the failure modes.

Jeremy
__________________

"Buster" in the '95

Our all-biodiesel family
1995 E300D (W124) . .239,000 miles My car
1996 E300D (W210) . .313,000 miles Wife's car
Santa Rosa population 170,685 (2012)
Total. . . . . . . . . . . . 722,685
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 08:07 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page