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 > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 03-21-2007, 11:30 AM
Bev Bev is offline
Registered User
 
Join Date: Mar 2007
Posts: 5
Headlights effect my idle, whats up?

I noticed lately that when I turn on my headlights it effects my idle. Headlights on my idle goes down, headlights off my idle goes back to normal. What should I check?
Thanks,
Bev

Reply With Quote
  #2  
Old 03-21-2007, 11:32 AM
dieseldan44's Avatar
Registered User
 
Join Date: Nov 2006
Location: Boston
Posts: 2,042
Hi Bev,

What is the model and year of the car?

dd
__________________
-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car
Reply With Quote
  #3  
Old 03-21-2007, 11:36 AM
Stevo's Avatar
Registered User
 
Join Date: Apr 2002
Location: NW WA
Posts: 6,299
Does turning on the AC have the same effect?
__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"
Reply With Quote
  #4  
Old 03-21-2007, 11:39 AM
Bev Bev is offline
Registered User
 
Join Date: Mar 2007
Posts: 5
It is a 1977 300D with 127,000 miles
Reply With Quote
  #5  
Old 03-21-2007, 11:43 AM
rrgrassi's Avatar
mmmmmm Diesel...
 
Join Date: Jun 2006
Location: Royse City Tx
Posts: 5,177
Have you made any mods to the lights, like adding 80/100 watt type? A big draw on current, makes the alternator harder to turn, resulting in lower idle speed from the resistance of the alt. Running the a/c causes this also.
__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K
Reply With Quote
  #6  
Old 03-21-2007, 11:44 AM
DIY or Die
 
Join Date: Apr 2006
Location: Los Angeles, California
Posts: 298
turning on your headlights will increase the load on the alternator. i'd start with the charging system...check all connections and the voltage regulator first. what's the voltage at the battery terminals with the car idling? and with it idling with the lights on?
__________________
1973 280 - Current Project Car
1979 240d - 100% Stock
1982 380sl - 100% Stock
1985 190e 2.3 - Heavily Modified
Reply With Quote
  #7  
Old 03-21-2007, 11:53 AM
Bev Bev is offline
Registered User
 
Join Date: Mar 2007
Posts: 5
I haven't changed anything related to the lights, I put a new sanden compressor in last fall. That is the only changes made. When I turn on the air it changes the idle, but that happens with my diesel suburban also and with other cars I have had. My headlights seem to change the idle much more than the air.
Thanks for your help guys!
Reply With Quote
  #8  
Old 03-21-2007, 12:19 PM
rrgrassi's Avatar
mmmmmm Diesel...
 
Join Date: Jun 2006
Location: Royse City Tx
Posts: 5,177
Quote:
Originally Posted by Bev View Post
I haven't changed anything related to the lights, I put a new sanden compressor in last fall. That is the only changes made. When I turn on the air it changes the idle, but that happens with my diesel suburban also and with other cars I have had. My headlights seem to change the idle much more than the air.
Thanks for your help guys!
How bright oar the lights? Does this happen with the parking lights also?

If you have a small short some where, that increases heat on the wire and amperage pull, which then makes the alt harder to turn.

If no short, resistance also creates heat and increases the call for amps to push the same voltage, resulting in the same harder to spin alt.

Get the charging system checked, and check all connections, making sure they are not getting hot.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K
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 04:20 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