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-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 02-02-2011, 11:05 AM
Alex300DT's Avatar
Registered User
 
Join Date: Jan 2011
Location: San Antonio
Posts: 48
Question Wiring mystery. 1987 300D

Hey guys, ive been searching the forums with no avail.

I'm trying to figure out what the previous owner has done to the OVP wiring circuit. Everything on the car works fine without the OVP relay being plugged in and when i have a fresh fuse and plug the whole relay into the car, everything stays on just like the key is still in on position. im wondering if anyone has come across anything like this before? and where would i look for bypassed ovp relay that affects the ignition?

thanks for any help

Reply With Quote
  #2  
Old 02-02-2011, 11:18 AM
Jeremy5848's Avatar
Registered Biodiesel User
 
Join Date: Mar 2006
Location: Sonoma Wine Country
Posts: 8,402
Please confirm: with the OVP relay in place, everything stays on? Engine continues to run, etc.?

Sounds like the OP had OVP problems and wired around the OVP to power its circuits directly from the ignition switch. Are there any signs of jumpers being added in the fuse box? Wires attached to fuse terminals?

I would then pull the OVP relay's bracket and see if there are any obvious signs of changes or additions to the wiring. Given the location of the OVP relay behind the battery, this is not a trivial task but it needs to be done.

The other "first place" I'd look is the ignition switch itself. With the driver's under-dash panel off you can look up under the dash to see if it's wiring has been obviously modified. [Most people doing things like this don't do a very neat job; you can tell just by looking that some of the wiring isn't factory.]
__________________

"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
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970
Reply With Quote
  #3  
Old 02-02-2011, 07:37 PM
Alex300DT's Avatar
Registered User
 
Join Date: Jan 2011
Location: San Antonio
Posts: 48
Yes, everything stays on just like i had never taken the key out, i did not get a chance to look at the car yet, (too cold outside) but i will take a look at the ignition switch and report what i see asap.
Reply With Quote
  #4  
Old 02-02-2011, 08:32 PM
vstech's Avatar
DD MOD, HVAC,MCP,Mac,GMAC
 
Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,835
I'm parting out an 87D soon, you're welcome to the harness.
__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
Reply With Quote
  #5  
Old 02-02-2011, 08:38 PM
babymog's Avatar
Loose Cannon - No Balls
 
Join Date: Jan 2006
Location: Northeast Indiana
Posts: 10,765
So the car starts, runs, tachometer/ABS/Cruise/A/C work normally, the car shuts off normally without the OVP relay?

Then with it plugged in, everything still works normally, but the car won't shut off, and tachometer remains working with no warning lights?

Just trying to clarify the original problem.

If this is the case, it sounds to me like the ignition switch has failed internally, is no longer linked to the lock cylinder. Shutting off the engine is achieved by a mechanical valve on the ignition switch assembly that opens and allows vacuum to the shutoff valve when you turn off the key.

You might want John's ignition switch assembly.
__________________

Gone to the dark side

- Jeff
Reply With Quote
  #6  
Old 02-02-2011, 10:15 PM
aaa aaa is offline
Registered User
 
Join Date: Nov 2008
Posts: 1,075
He might want to simply check if his vacuum system's ok, and set the OVP issue aside for now since it has nothing to do with the engine continuing to run.
Reply With Quote
  #7  
Old 02-04-2011, 03:25 PM
Alex300DT's Avatar
Registered User
 
Join Date: Jan 2011
Location: San Antonio
Posts: 48
Arrow

Hey everyone. Thanks for the replies. After checking the vac shutoff, tearing the dash apart and not finding anything weird there I went back to the engine bay and found a wire going from the switchover valve towards the governor. I have no idea what the previous owner was trying to accomplish with that but it seems to be working perfect now.

Thanks again.
Alex.

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 11:40 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page