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 > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 12-02-2008, 07:15 PM
Registered User
 
Join Date: Jul 2008
Posts: 1,236
Cool Busted coolant temp sensor - workaround

So, I was replacing the coolant temp sensor that goes to the temp gauge. While I was in there I decided to check out the main dual-element coolant temp sensor. Well, it crumbled into pieces and the wires pulled out of it, making it totally dead. Sure enough, the car wouldn't run at all without it.

Did I mention that I did this in the parking lot at work, totally stranding myself?

After frantically calling parts stores (none had the part), I was running out of options, so here's what I did...

1) I took the half of the sensor that has the 4 pins on it and removed it from the plug
2) I cleaned up the 4 pins (on the side that used to be inside the sensor) and removed the old wires from the posts.
3) I consulted WIS and looked up the temperature coefficient table for the temp sensor
4) I took two 470 ohm resistors, and soldered them to the posts in the criss cross pattern specified in WIS.
5) Insulated with shrink wrap and electrical tape.
6) Plugged my new "sensor" back into the sensor plug.

Now the car starts, but runs rough until it's warmed up. This is not surprising, because I have tricked the computer into thinking that the coolant temp is around 60 celsius.

Once the motor gets warm, the engine will run well enough to get me home tonight. I fully expect soot in my tailpipe.

Just thought I'd post this in case any of you wind up in a similar pickle.


Cheers!


-tinypanzer

Reply With Quote
  #2  
Old 12-02-2008, 09:42 PM
LUVMBDiesels's Avatar
Dead on balls accurate...
 
Join Date: Aug 2006
Location: Red Lion,Pa
Posts: 2,207
smart thinking
__________________
"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

Current
Monika '74 450 SL
BrownHilda '79 280SL
FoxyCleopatra '99 Chevy Suburban
Scarlett 2014 Jeep Cherokee
Krystal 2004 Volvo S60
Gone
'74 Jeep CJ5
'97 Jeep ZJ Laredo
Rudolf ‘86 300SDL
Bruno '81 300SD
Fritzi '84 BMW
'92 Subaru
'96 Impala SS
'71 Buick GS conv
'67 GTO conv
'63 Corvair conv
'57 Nomad
Reply With Quote
  #3  
Old 12-03-2008, 03:47 PM
Registered User
 
Join Date: Jul 2008
Posts: 1,236
Well, it worked..... Sort of.... The car ran fine and got me home, but starting it when it was 30 degrees outside was difficult. I had to hold down the accelerator and rev it to 2K for a couple minutes before it would hold an idle and not stall. After that, it ran fine..... Plenty of power, smooth idle.

Still not gonna drive it until I get the new sensor.... Time to call Phil!

BTW- Phil, you were right, the single pole temp sensor was the culprit for my incorrect readings on my temp gauge.... Should have just ordered both of the temp sensors at the same time.


-tp
Reply With Quote
  #4  
Old 12-09-2008, 09:43 AM
Gerard's Avatar
91 300CE M103: 80 450SEL
 
Join Date: Nov 2001
Location: Dublin, Ireland
Posts: 112
You could get a variable resistor, have it sticking out of the dash, nice brass knob on it, put a few marks on it for various temps, just like a real vintage car!
G


Quote:
Originally Posted by tinypanzer View Post
Well, it worked..... Sort of.... The car ran fine and got me home, but starting it when it was 30 degrees outside was difficult. I had to hold down the accelerator and rev it to 2K for a couple minutes before it would hold an idle and not stall. After that, it ran fine..... Plenty of power, smooth idle.

Still not gonna drive it until I get the new sensor.... Time to call Phil!

BTW- Phil, you were right, the single pole temp sensor was the culprit for my incorrect readings on my temp gauge.... Should have just ordered both of the temp sensors at the same time.


-tp
Reply With Quote
  #5  
Old 12-09-2008, 05:49 PM
Registered User
 
Join Date: Jul 2008
Posts: 1,236
That's funny, my colleague suggested the same thing. Y'know, that would be a real easy way messing with rich/lean. Just drop the "sensor reading" down a few degrees, and that should richen the mixture.

Incidentally, I was correct when I stated that I fully expected soot in my tailpipe. I got plenty of soot.


-tp
Reply With Quote
  #6  
Old 12-10-2008, 10:06 AM
slk230red's Avatar
WECO Installer
 
Join Date: Jul 2006
Location: Tampa, FL
Posts: 818
Quote:
Originally Posted by tinypanzer View Post
That's funny, my colleague suggested the same thing. Y'know, that would be a real easy way messing with rich/lean. Just drop the "sensor reading" down a few degrees, and that should richen the mixture.

Incidentally, I was correct when I stated that I fully expected soot in my tailpipe. I got plenty of soot.


-tp
Hi tinypanzer,

Just curious, what year/model/engine do you have?
__________________

1993 190E 2.3
2001 SLK230
1971 LS5 (454) Corvette Convertible
Reply With Quote
  #7  
Old 12-10-2008, 05:21 PM
Registered User
 
Join Date: Jul 2008
Posts: 1,236
It's a '90 300SE (M103 motor).....



-tp
Reply With Quote
  #8  
Old 12-10-2008, 05:45 PM
pawoSD's Avatar
Dieselsüchtiger
 
Join Date: Oct 2004
Location: Grand Rapids, MI
Posts: 15,108
Unplugging the idle valve will allow for good cold starts, and runs ok when warm. Thats what I did...I have a new temp sensor coming friday....hopefully that fixes my problem.
__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 83k - mine - (OC-85,500)
'17 Metris(VITO!) - 13k - wifes (OC-17k)
'01 E320 Wagon - 159k - mine (OC-160,000)
'01 E320 - 179k - dad's (OC-182,500)
'07 E350 Wagon - 131k - dad's (OC-132,500)
'01 SL500 - 51k - dad's (OC-52,000)
'16 E400 4matic Sedan - 57k - Brothers (OC-64,000)
Reply With Quote
  #9  
Old 12-10-2008, 06:03 PM
Registered User
 
Join Date: Jul 2008
Posts: 1,236
Did you measure your temp sensor?


I posted how in another recent thread......


-tp
Reply With Quote
  #10  
Old 12-10-2008, 06:34 PM
pawoSD's Avatar
Dieselsüchtiger
 
Join Date: Oct 2004
Location: Grand Rapids, MI
Posts: 15,108
Quote:
Originally Posted by tinypanzer View Post
Did you measure your temp sensor?


I posted how in another recent thread......


-tp
No.....but I'm swapping it all the same, it looks old and brittle....
__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 83k - mine - (OC-85,500)
'17 Metris(VITO!) - 13k - wifes (OC-17k)
'01 E320 Wagon - 159k - mine (OC-160,000)
'01 E320 - 179k - dad's (OC-182,500)
'07 E350 Wagon - 131k - dad's (OC-132,500)
'01 SL500 - 51k - dad's (OC-52,000)
'16 E400 4matic Sedan - 57k - Brothers (OC-64,000)
Reply With Quote
  #11  
Old 12-10-2008, 07:31 PM
Registered User
 
Join Date: Jul 2008
Posts: 1,236
Brittle is the operative word. I went to check mine and it totally disintegrated.

-tp

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 07:07 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page