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 01-24-2011, 07:59 PM
LandYaghtLover's Avatar
Registered User
 
Join Date: Jun 2010
Location: Green Bay, WI
Posts: 1,339
W126 Strange trans behavior when cold!

This is a weird one. So for the past few cold (very cold) starts the trans does not shift well at all. I get in and fire her up. Sometimes even let it warm up a while. No matter. When I take off the trans holds gears for dear life. Also the economy gauge stays further than normal to the right. Often there will be surging and overall the car feels sluggish.

However. If I pull over, kill the engine and immediately fire it up. All is normal. Car is more responsive and shifting is where it usually is.

The car will behave oddly well past warm up. Does not appear to be heat related since even when pretty cold yet a restart will "fix" things.

Any ideas?
__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car
Reply With Quote
  #2  
Old 01-26-2011, 04:26 PM
Hit Man X's Avatar
I LOVE BRUNETTES
 
Join Date: Sep 2004
Location: FUNKYTOWN
Posts: 8,908
Thumbs up

Does not sound trans related as the trans is all mechanical for shifting, maybe the car is not charging properly? CIS computer loose? Grounds?
__________________
I'm not a doctor, but I'll have a look.

'85 300SD
'87 300SDL
'89 300E
'90 300SEL
'91 560SEL

Eight others from IH, BMW, GM, Ford, and Volvo.

Liberty will not descend to a people; a people must raise themselves to liberty.
[/IMG]
Reply With Quote
  #3  
Old 01-26-2011, 08:16 PM
LandYaghtLover's Avatar
Registered User
 
Join Date: Jun 2010
Location: Green Bay, WI
Posts: 1,339
Well my alt squeaks badly. Figured just the bearing. But if I turn on one heated seat the headlight dim noticeably. So the alt is on my light of projects. Probably rebuilt it. The brushes on it are fine. I had removed them and cleaned all the contacts as well as cable ends. In fact I did any and every cable end in the engine bay I could find.

But if electrical, why would a "reboot" of the car fix it? And it certainly fires up nicely.
__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car
Reply With Quote
  #4  
Old 01-26-2011, 10:29 PM
Hit Man X's Avatar
I LOVE BRUNETTES
 
Join Date: Sep 2004
Location: FUNKYTOWN
Posts: 8,908
Thumbs up

Quote:
Originally Posted by LandYaghtLover View Post
Well my alt squeaks badly. Figured just the bearing. But if I turn on one heated seat the headlight dim noticeably. So the alt is on my light of projects. Probably rebuilt it. The brushes on it are fine. I had removed them and cleaned all the contacts as well as cable ends. In fact I did any and every cable end in the engine bay I could find.

But if electrical, why would a "reboot" of the car fix it? And it certainly fires up nicely.


I have had vehicles restart and run better with issues. :shrug: Maybe lazy solder within the CIS computer?

Reboots seem to work on PC's running Windows.



Stock alt is, what, 80A? Last time I used my heated seats it could only keep two on low temp setting from memory.
__________________
I'm not a doctor, but I'll have a look.

'85 300SD
'87 300SDL
'89 300E
'90 300SEL
'91 560SEL

Eight others from IH, BMW, GM, Ford, and Volvo.

Liberty will not descend to a people; a people must raise themselves to liberty.
[/IMG]
Reply With Quote
  #5  
Old 01-27-2011, 12:26 AM
LandYaghtLover's Avatar
Registered User
 
Join Date: Jun 2010
Location: Green Bay, WI
Posts: 1,339
80 amp is what I have read also. I would like to go 120 if even possible. I can keep all four seats on high heat unless I have rear defrost and headlights on, then one or two will start blinking indicating there is low voltage. Or the defrost may blink also.

I will have to dig into it further. The odd thing is that its VERY consistent. It will always happen. So the past two cold starts I fired it up for only about 15 seconds. Then shut her down and started up again. No issue.

Whatever it is, its confusing. Wonder if its vacuum related instead.
__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car
Reply With Quote
  #6  
Old 01-27-2011, 07:18 AM
Hirnbeiss's Avatar
ich fahre, also bin ich
 
Join Date: Mar 2002
Location: South Florida
Posts: 1,549
the tranny is vacuum controlled, and the economy gage is driven by vacuum, so there may be a connection. check the vacuum hose to the tranny, then check the vacuum modulator on the trans.
__________________
Prost!
Reply With Quote
  #7  
Old 01-27-2011, 10:51 AM
LandYaghtLover's Avatar
Registered User
 
Join Date: Jun 2010
Location: Green Bay, WI
Posts: 1,339
Modulator and vac hose are new to trans. In fact, all the rubber on the engine is new. Either way, its the restart that is odd since it fixes the issue. Trying to think what vacuum part could do that trick and all I think of is the idle valve. But if that was open wide I would think rough/high idle.
__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car
Reply With Quote
  #8  
Old 01-27-2011, 11:03 AM
Registered User
 
Join Date: Oct 2005
Posts: 158
i've noticed that, with the cold temperatures, my transmission also is a bit sluggish to shift for the first mile or so. Once the oil gets warmed up a bit it shifts normally. This has been my experience with other cars so I'm not too worried about it at the moment.
.
I could be wrong but I don't thinking idling the car to allow it to warm up will help warm up the transmission as the car is in park and there would little if any fluid flowing.
Reply With Quote
  #9  
Old 01-27-2011, 11:15 AM
LandYaghtLover's Avatar
Registered User
 
Join Date: Jun 2010
Location: Green Bay, WI
Posts: 1,339
Quote:
Originally Posted by London380sl View Post
I could be wrong but I don't thinking idling the car to allow it to warm up will help warm up the transmission as the car is in park and there would little if any fluid flowing.
Unfortunately I wish you were right, but thats not the case here. Originally I may have suspected just that since it makes sense. But the problem I am having remains the same well after warm up as mentioned above. I usually let the car warm up for about 5 minutes every morning anyway. But if I do or not, same issue with the boggy engine and trans holding gear. And it will do it even after a half hour or more of driving. But if I restart the car, even after just starting it up with no warm up, it will shift fine. Its pretty much 100% predictable. And its the weirdest problem I have ever had with a car!
__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car
Reply With Quote
  #10  
Old 01-28-2011, 05:29 PM
david s poole
 
Join Date: Mar 2005
Location: dallas
Posts: 1,822
the only thing i can think of is the kickdown solenoid that it might be sticking on causing the holding of lower gear.
__________________
David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
Reply With Quote
  #11  
Old 01-29-2011, 01:51 AM
LandYaghtLover's Avatar
Registered User
 
Join Date: Jun 2010
Location: Green Bay, WI
Posts: 1,339
Good thought. But I already checked that. And I rarely ever press the pedal far enough to ever activate it.

However, your idea is a pretty close description to the issue. Maybe I will disconnect it and see what happens. The switch itself may be bad. Worth a shot.
__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car
Reply With Quote
  #12  
Old 01-29-2011, 09:21 AM
Hirnbeiss's Avatar
ich fahre, also bin ich
 
Join Date: Mar 2002
Location: South Florida
Posts: 1,549
It's been a while since I had an analog museum piece, and even longer since I drove one in iceball country, but I have to think it is related to the throttle linkage. The control pressure cable, connected to the throttle linkage, is what determines the shift point. On my 201 and 124 I don't recall any cold-start mechanism that affected the linkage, but on yours maybe there is? Is there anything that performs a choke function when cold that pushes on the linkage, and is supposed to release when cold? Having an open throttle plate will lower your vacuum too, giving the poor economy reading.
__________________
Prost!
Reply With Quote
  #13  
Old 01-29-2011, 11:42 AM
LandYaghtLover's Avatar
Registered User
 
Join Date: Jun 2010
Location: Green Bay, WI
Posts: 1,339
Beats me. Just odd that the problem remains until a restart, no matter how cold or warm the engine.
__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car
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 10:04 PM.


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