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 07-25-2010, 01:39 AM
Registered User
 
Join Date: Aug 2007
Location: Southern California
Posts: 399
M103 R&R, now low idle?

I just finished a little project on my 1993 190E 2.6 where I replaced the head gasket, cleaned out the intake components, replaced the timing chain rails.

The car started up on the first attempt of firing it up this afternoon and runs great under throttle, but I am having severe issues at idle.

at idle, the RPM drops to around 500 rpm when I coast to a stop and put the car in neutral. at this point, the vacuum is very low and the oil pressure is very low.

I will investigate tomorrow by checking compression, OVP, and IACV, but i just find it strange since my motor was idling just fine before the job.

any ideas? any specific tests i should run?

Reply With Quote
  #2  
Old 07-25-2010, 12:30 PM
slk230red's Avatar
WECO Installer
 
Join Date: Jul 2006
Location: Tampa, FL
Posts: 820
When the engine is running put your hand on the Idle Control Valve. Do you feel it pulsating?
__________________

1993 190E 2.3
2001 SLK230
1971 LS5 (454) Corvette Convertible
Reply With Quote
  #3  
Old 07-25-2010, 05:09 PM
Registered User
 
Join Date: Aug 2007
Location: Southern California
Posts: 399
Quote:
Originally Posted by slk230red View Post
When the engine is running put your hand on the Idle Control Valve. Do you feel it pulsating?
have not tested this yet.

but I did some more testing today.

Throttle Valve Switch works as defined in the manual

pin 1 = idle contact
pin 2 = ground
pin 3 = full load contact.

pin 1 and 2 are shorted when idling, moving throttle linkages away from idle opens the circuit.

pin 2 and 3 are shorted at full load only, moving throttle away from full load opens the circuit.

IACV still operates when 12V is applied across the terminals. next is to check the OVP relay and try replacing with spares that are laying around.

Compression tests read good,

1: 175 psi
2: 180 psi
3: 180 psi
4: 180 psi
5: 180 psi
6: 175 psi

Tested at normal op temperature with allowed 10 compression strokes per cylinder and all spark plugs removed.

any one else have any inputs?
Reply With Quote
  #4  
Old 07-25-2010, 05:53 PM
slk230red's Avatar
WECO Installer
 
Join Date: Jul 2006
Location: Tampa, FL
Posts: 820
One more thing to check is the Micro-Switch at the throttle linkage assembly. Make sure it's closed at the idle position.
__________________

1993 190E 2.3
2001 SLK230
1971 LS5 (454) Corvette Convertible
Reply With Quote
  #5  
Old 07-25-2010, 07:33 PM
Registered User
 
Join Date: Aug 2007
Location: Southern California
Posts: 399
yes the microswitch is working properly.

I narrowed my problem down to either the IACV or the OVP relay. I swapped both units from my working M103 W124 and my problems magically went away. I am putting the original OVP back in place to see if problem reoccurs.

edit:

original OVP, car still runs fine. it is the IACV. the 300E is now idling funny.


Last edited by John5788; 07-25-2010 at 08:39 PM.
Reply With Quote
Reply

Bookmarks


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 02:02 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