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 08-11-2003, 01:59 AM
Registered User
 
Join Date: Aug 1999
Location: ajax, ontario, canada
Posts: 773
what is the purpose of the throttle microswitch?

what is the purpose of the microswitch near the throttle linkage?

mine is has recently broken - the arm that presses on the switch broke, but the switch itself is still ok, although it can no longer be activated by the throttle linkage. As a result, my idling speed is very high on startup if the engine is cold. This was pointed out to me by my mechanic, and on startup, I sometimes need to manually activate the switch just to get the idling back to somewhere near normal.

I also noticed that my engine's torque is not so good in the midrange, and when I give it the boot, I sense irregularities in the torque curve, as the engine winds itself up under load. My guess is that this could also be related to the microswitch, because I noticed this only recently.

mine is an M103 2.6 engine.

Reply With Quote
  #2  
Old 08-11-2003, 09:20 AM
Super Moderator
 
Join Date: Apr 2000
Location: Falls Church, VA
Posts: 5,318
It tells the engine management computer if the throttle is at idle or full acceleration. So if the switch position is does not reflect what the throttle is doing, your EHA is trying to respond to faulty data. Like it may think you are wide open and go to full enrichment when you are just driving normally.
__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
Reply With Quote
  #3  
Old 08-11-2003, 09:28 AM
Moderator
 
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
Actually I think he is referring to the decel switch and I'm not sure what it does overall. I suppose its intended purpose is to signal closed throttle fuel fuel cut-off under deceleration.

It also plays a part in closed throttle recognition for idle control. I've never been exactly sure why they needed a second idle recognition switch when they also had the throttle switch doing the same thing.

I'm guessing this is what is being talked about as the throttle switch is not visable until disassembly.
__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician
Reply With Quote
  #4  
Old 08-11-2003, 09:45 AM
Super Moderator
 
Join Date: Apr 2000
Location: Falls Church, VA
Posts: 5,318
Corrected.

I was looking at the decel micro switch, and the diagram shows a "Full Load" position. But upon closer examination, that position has no connection to the control unit.
__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
Reply With Quote
  #5  
Old 08-11-2003, 10:55 AM
Registered User
 
Join Date: Jul 2001
Location: SoCal
Posts: 1,303
"I was looking at the decel micro switch, and the diagram shows a "Full Load" position. But upon closer examination, that position has no connection to the control unit."

You are looking at the decel microswitch on the car, and the throttle position switch on the schematic. As Steve said, these are different items, in different locations. The TPS is bolted to the side of the throttle body, at the butterfly shaft. The decel microswitch is on the throttle linkage, near the accelerator cable.

Steve
__________________
'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7
Reply With Quote
  #6  
Old 08-11-2003, 11:10 AM
Super Moderator
 
Join Date: Apr 2000
Location: Falls Church, VA
Posts: 5,318
Nope, this came off right off the the schematic on the CD (S27/2) . Send me an email if you want a copy.
__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
Reply With Quote
  #7  
Old 08-11-2003, 11:49 AM
Registered User
 
Join Date: Jul 2001
Location: SoCal
Posts: 1,303
Ok. Send the part of the schematic that shows both the decel switch and both switches in the TPS. I would be curious to see what is going on here.

Steve
aq433 at hotmail dot com
__________________
'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7
Reply With Quote
  #8  
Old 08-11-2003, 12:55 PM
Registered User
 
Join Date: Jul 2001
Location: SoCal
Posts: 1,303
Ctaylor, thanks for the schema. However, it says just what I did - the decel switch shows just one closure, while the TPS has two - one for full throttle, and one for idle. The TPS is NOT the microswitch on the linkage - that is the decel switch. The TPS is bolted onto the side of the throttle body itself.

Steve

__________________
'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7
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 11:29 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2023, 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