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 ShopForum > Technical Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 06-30-2003, 10:12 PM
Lurch's Avatar
Member
 
Join Date: May 2003
Location: Toronto
Posts: 53
Question Troubleshooting teaser - w126

1986 560 sel

On a trip this past weekend, I was floating along @ 120km/hr with the cruise on when i encountered the problem. My observations were as follows:

Son had been adjusting the rear seat
A/C began to lose cool
Speed began to slowly drop (120 to 105)
Revs climbed higher (slow rise to ~ 3500rpm)
Economy guage was nailed to the right.

I took it off cruise and the tranny shifted dropping the revs back to normal (near 2000 for just over 100 kph)
Economy guage was still showing full to the right as I feathered the pedal to keep speed to the nearest exit.
Pulled into a gas station and shifted into park.
Idle was fine, revved with no probs
Checked tranny fluid - okay.
Shut down to check oil - that was okay.
Went to start up again and the starter kept turning even when i pulled the key out of the ignition.... I had to lift the terminal off the battery to kill it.

Towed to shop... (Canadian Tire of all places)
Reply With Quote
  #2  
Old 06-30-2003, 10:51 PM
Registered User
 
Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
Low voltage does all sorts of strange things in the W126. Did your wipers start up too? This has been known to happen. The cruise will not work properly at low voltage, the gauges will go nuts, and the compressor will drop off line, ditto for the climate control -- it defaults to full heat defrost.

Get the battery checked, it may have a bad cell so the voltage drops. Get the alternator checked too, you may have blown a diode.

Check your fuses too, in case something got hot and melted, shorting things out.

Could also be a fried ignition switch, completely unrelated to the rear seat adjustments

My brother didn't show the kids the rear seat adjuster on purpose.......

Peter

Peter
__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
Reply With Quote
  #3  
Old 06-30-2003, 11:37 PM
MikeTangas's Avatar
Senior Member
 
Join Date: Apr 2000
Location: So. Cal
Posts: 4,430
I know that feeling. When I was resurrecting the 560 I was sitting there idling the engine and decided to cycle the sunroof. Everytime I would try to close the roof the RPM would drop, almost to the point of dying, then pick up and idle fine as soon as the switch was released. Replacing the regulator cured that.

I have a bum seat adjustment switch in the back and purposely am not replacing it. It keeps the kids from jacking with the seat.
__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.
Reply With Quote
  #4  
Old 07-01-2003, 01:04 AM
Senior Member
 
Join Date: Mar 2001
Location: Accokeek, MD
Posts: 683
I second what Mike has to say. My guess is that because the car has been on the road for a few years... the brushes of the voltage regulator are worn and no longer producing sufficient voltage to keep the battery at peak charge. The seat games simply set things into motion.
__________________
Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra
Reply With Quote
  #5  
Old 07-01-2003, 02:13 PM
Lurch's Avatar
Member
 
Join Date: May 2003
Location: Toronto
Posts: 53
Talking Fixed

Problem turned out to be a corroded wire connection at the fuel pump.... go figure.

Billed 2 hours of time to diagnose & fix, no parts... bargain city IMO.
Reply With Quote
  #6  
Old 07-01-2003, 02:43 PM
Registered User
 
Join Date: Apr 2002
Location: a space in time
Posts: 132
Good Deal..

Considering the reputation that some of the Canadian tire service centres have, it sounds like you did extremely well.
__________________
Mithra

93 sl600
93 600sel

A mercedes is an inanimate object and therefore must respond to logic and reason.
Reply With Quote
  #7  
Old 07-01-2003, 04:22 PM
hedpe's Avatar
Registered User
 
Join Date: Oct 2001
Posts: 507
I love troubleshooting the W126 so much better than the 500E, when the 500E has a problem, it SERIOUSLY has a problem, but the W126 is fun to fix
__________________
Own:
2013 C300 4matic
2009 C300 4matic

Owned:
2001 E320 Sport
1992 500E
1989 300SEL
Reply With Quote
  #8  
Old 07-01-2003, 05:40 PM
Senior Member
 
Join Date: Mar 2001
Location: Accokeek, MD
Posts: 683
I have reservations about the fuel pump wire being the cause of the symtoms you first described. Before exhaling I would check the output voltage of the altenator and also make sure the battery does not have a bad cell.
__________________
Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra
Reply With Quote
  #9  
Old 07-01-2003, 06:14 PM
Lurch's Avatar
Member
 
Join Date: May 2003
Location: Toronto
Posts: 53
Earl

Seems to be fine now. Just did 350 km with a couple of short stops and the "feel" is as good as it was when I bought it.... IOW pretty decent. Noticed a bit more punch when I hit the giddyup pedal which may have slowly deteriorated prior to the problem slowly enough that I didn't clue in.

Perhaps one of the techs on the board can shed some light on why the starter would not disengage even when the key was turned off and pulled out. The CT mechanic speculated that perhaps the ECU was not getting a signal that it was firing and would not disengage the starter until it received a firing signal.

As part of his troubleshooting, he poured a small amount of gas into the air intake and cranked it... once it caught a spark the starter disengaged.

His somewhat sheepish comment was that he moved away from Toronto to get away from cars like that.

I'll keep an eye on it for a bit anyway and have it looked over later this week by my usual tech for any electrical heebee-jeebees.
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 07:32 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page