1986 420-SEL High Idle

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1986 420-SEL High Idle

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1986 420-SEL High Idle - 5/5/2007 10:28:23 PM

docsbbs

Posts: 2
Joined: 5/5/2007
Status: offline Greetings..

My old trusty 1986 420-SEL just started idling at about 2500 RPM. I have checked all the linkage for proper operation. Also checked for vacuum leaks. I am suspecting the idle air control device may be gummed up, or just plain bad. But there are no warning light present in the cluster. Any suggestions other than replacing it??

Post #: 1

RE: 1986 420-SEL High Idle - 5/15/2007 2:53:08 PM

irantehran

Posts: 19
Joined: 4/17/2007
Status: offline you get no warnning light or others, idle contol relay is on firwall is bad it is on the center of the fire wall with two 10 mm nuts attached, if you send me the part number i may have a good used one,

(in reply to docsbbs)

Post #: 2

RE: 1986 420-SEL High Idle - 5/15/2007 5:30:48 PM

docsbbs

Posts: 2
Joined: 5/5/2007
Status: offline Thanks.. I will check into it tomorrow..

(in reply to irantehran)

Post #: 3

RE: 1986 420-SEL High Idle - 8/17/2008 8:47:10 PM

nescid

Posts: 31
Joined: 7/22/2008
Status: offline If the idle control relay is not the culprit, it could be your Idle Control Valve. I think I do have a very good clean one.
nes

(in reply to docsbbs)

Post #: 4

RE: 1986 420-SEL High Idle - 8/18/2008 7:51:14 PM

MBENZ300SD

Posts: 20
Joined: 12/25/2007
Status: offline check the overload protection relay, there is a 10 amp fuse on top of it, if it is blown then it will cause your engine to idle high, it is located next to the fuel pump and klima control relays just to the left side of the brake booster, it has a red top with a clear lid that pops up, check it before you go spend $$$$$$ replacing parts that are not bad, hope this helps out.

(in reply to docsbbs)

Post #: 5

RE: 1986 420-SEL High Idle - 8/19/2008 6:32:35 PM

chassis221

Posts: 778
Joined: 2/17/2007
From: Philadelphia, Pa
Status: offline
this is a pic of the idle speed control valve, located at the front of the aircleaner partially under it. usually when you unplug it the idle should change. if you unplug it and nothing happens it could be a bad valve.

Thumbnail Image

Attachment (1)

_____________________________

Philadelphia, Pa
Certified MB Master

(in reply to docsbbs)

Post #: 6

RE: 1986 420-SEL High Idle - 9/22/2008 8:25:13 AM

makis30

Posts: 4
Joined: 9/16/2008
Status: offline did you figure it out?? i have the same problem but cannot recieve a response. i would really appreciate any advise you can give.

(in reply to docsbbs)

Post #: 7

RE: 1986 420-SEL High Idle - 9/22/2008 9:44:20 PM

MBTECHINFO

Posts: 88
Joined: 8/13/2007
Status: offline CHECK THE IDLE CONTACT SWITCH, SERIOUSLY

(in reply to makis30)

Post #: 8

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