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 11-15-2009, 10:19 PM
Registered User
 
Join Date: Sep 2009
Location: south texas
Posts: 91
1987 560sl high idle back

Well it seems my high idle (1800 rpm) issue is back, started this morning andwon't go away! Before, (last week) I followed some advce/tips, and re-soldered connections on the idle speed control module and the high voltage relay, removed and cleaned the idle speed solenoid, and between all that it was fixed! or so I thought, maybe I missed a bad solder joint on the module, or maybe the idle speed solenoid still crudded up? The idle speed solenoid was pretty clean when i took it off, I applied 12 volts to check it's operation and even blew in one side of it to make sure it was "sealing" good when energized. Any more ideas anyone? (I'm sure I missed something, as all of you advice was expert, probably something on my part)
Any more suggestions would be just too cool! Unfortunatly I have to drive thecar to work like this, my "86 Plymouth Reliant is being used by my son for school. I'm sure driving it like this is not good and it is also a hassle/probably dangerous!

Thanks,
Dwight Daymen (userID ddayme)

Reply With Quote
  #2  
Old 11-15-2009, 11:00 PM
Registered User
 
Join Date: Sep 2009
Location: south texas
Posts: 91
Addition to above: may not br related, but ever since I've had this car, 5 years, the a/c compressor would not come on unless i unplugged the conector on the temp. sensor? (it has two prongs/wires) and plugged it back in a manner where only one wire was connected to it.

Thanks,
DDaymen
Reply With Quote
  #3  
Old 11-16-2009, 08:17 AM
Moderator
 
Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
The idle speed control unit is the most likely problem, if it is getting power, ground, & RPM signal at pin TD.
__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator
Reply With Quote
  #4  
Old 11-16-2009, 10:18 PM
Registered User
 
Join Date: Sep 2009
Location: south texas
Posts: 91
What would pin TD be?
Thanks
Reply With Quote
  #5  
Old 11-17-2009, 08:03 AM
Moderator
 
Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
TD=RPM signal from the ignition module.

Should be around 7.5-8Vdc.

If that signal was missing the fuel pump relay wouldn't allow pumps to run as well.
__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator
Reply With Quote
  #6  
Old 11-17-2009, 02:18 PM
Registered User
 
Join Date: Sep 2009
Location: south texas
Posts: 91
I guess I'm confused, as I don't know where the ignition control module is. Before, I re-soldered some solder joints on the idle control module, cleaned the idle speed solenoid, and that fixed it for 3 days, then it suddenly came back. One reason I can't check the various voltages to the module/from the module is that I have no schematic/repair literature/pictures, so I am kind of working "blind", I would order a factory repair cd, but unfortunatly it is not in my budget (the hospital where I work has cut our hours down to 3 days a week!) I guess I will have to wait untill I can get a repair cd to effectively repair this problem!

Thanks for the help,
-ddayme
Reply With Quote
  #7  
Old 11-18-2009, 02:13 AM
Registered User
 
Join Date: Sep 2009
Location: south texas
Posts: 91
I redid everything I did before, clean idle solenoid, go over solder joints on idle speed control module, but no effect! just that high idle. Somewhere in this website I saw mention of where you can get a re-built idle speed control module, does anyone know the name of this place? I may have to try replacing said module, and it will have to be a re-built/used one.

Thanks,
-ddayme
Reply With Quote
  #8  
Old 11-18-2009, 07:19 AM
Registered User
 
Join Date: Jan 2003
Location: Matthews, NC
Posts: 1,356
Before buying anything, try this. With the engine running, move, shack,twist, push on, or pull on the plug at the idle control unit. I went through every thing you have already done and still had problems with my 500 and after doing the above, found one or more of the signals wasn't making it through the plug. I very carefully removed each wire from the plug (make a chart of wire colors to location before you begin) and close each one up just a little. Spray just a little WD-40 or contact cleaner in each hole and replug and test again. Mine has been working great now for the last 2 years or so.
This is the first thing I do now if I have problems with electronic components. It is the best way to find bad solder joints and connectors.
Good luck,

Paul
__________________
84 500 SEL (307,xxx miles)
Reply With Quote
  #9  
Old 11-18-2009, 09:16 AM
Registered User
 
Join Date: Sep 2009
Location: Great State of Texas
Posts: 440
You applied voltage to the solenoid - did you check to see if the wire you're connecting to it had any voltage coming out of it? No voltage to solenoid = high idle.
__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.
Reply With Quote
  #10  
Old 11-18-2009, 09:58 AM
Registered User
 
Join Date: Sep 2009
Location: south texas
Posts: 91
Yes, I checked the voltage to the solenoid, it was only .008! not right, I,m sure.
Reply With Quote
  #11  
Old 11-18-2009, 12:52 PM
1990 190E 2.6 Automatic
 
Join Date: Jul 2009
Posts: 64
Bad OVP relay??
Reply With Quote
  #12  
Old 11-18-2009, 03:57 PM
Registered User
 
Join Date: Sep 2009
Location: south texas
Posts: 91
Re-soldered it, that was one of the things I did, but Maybe I missed something, I will remove it again and check the solder joints. Wish there was a way to check these out without replacing them/swapping with known good ones!
Reply With Quote
  #13  
Old 11-18-2009, 04:14 PM
mramay's Avatar
Mike R.
 
Join Date: Jan 2007
Location: Las Vegas
Posts: 152
Quote:
Originally Posted by workerunit View Post
Bad OVP relay??
Bad 10-amp fuse in the OVP red-topped unit?? BTDT, $1.00 part.
__________________
There is a very fine line between "hobby" and "mental illness."
FrankenBenz: '87 560SEC with an '02 cammed LS6 and custom 4L60E.
Bling: '87 560SEC, ported/polished, lowered
Lisa: '87 560SEL, lowered
Reply With Quote
  #14  
Old 11-18-2009, 07:12 PM
Registered User
 
Join Date: Sep 2009
Location: Great State of Texas
Posts: 440
Idle control unit just might be bad. Just because you re-solder connections doesn't mean the guts are going to come back to life.

OVP could be bad, too, but you should be getting an ABS light. Don't just visually check the fuse on it, either - ohm it out. I've seen plenty of fuses that look good that were "popped".

Some of the inputs into the ICU include vehicle speed, rpm, engine temp, compressor enable, idle input, and most importantly - ground. Bad/dirty grounds cause more "strange" problems than anything else.
__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.
Reply With Quote
  #15  
Old 11-19-2009, 12:49 AM
Registered User
 
Join Date: Sep 2009
Location: south texas
Posts: 91
When I re-soldered the idle control module, the car worked for 3 days, but that may have just been a coincident. I checked the fuse on the ovp with an ohm meter, it was good, maybe there is a bad ground somewhere< any ideas where to look? as far as the anti-lock light it does not light up at all, just an unmarked light next to it. I had read about a ground by the coil, but wasn't sure just where that ground was.
Didn't get home till late, didn't even look at the car today!

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 07:11 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, 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