Help with 71 mercedes 250-no start - Mercedes-Benz Forum

 
LinkBack Thread Tools Display Modes
post #1 of 3 (permalink) Old 03-07-2010, 06:36 AM Thread Starter
BenzWorld Newbie
 
Date registered: Mar 2010
Posts: 1
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
(Thread Starter)
Help with 71 mercedes 250-no start

Bought a 1971 250 Mercedes sedan. Will not start. When tested, no spark. Everything appears to be grounded both sides of coil and breaker points, no power. Has a ignition control module that doesn't seem to belong. Cannot find an accurate wiring diagram. Any help to lead in the right direction???
tucker1191 is offline  
Sponsored Links
Advertisement
 
post #2 of 3 (permalink) Old 03-07-2010, 08:34 PM
BenzWorld Member
 
Date registered: Apr 2008
Posts: 86
Mentioned: 1 Post(s)
Quoted: 2 Post(s)
Did it run when you bought it? As a starting point, I'd start by closely examining the points, cap and rotor. Make sure the points are gapped properly and not excessively pitted. If they're badly pitted your condenser is either bad, or the wrong impedence. Make sure the rotor center contact is good and making contact with the cap when installed. You'll see the wear witness marks. Make sure the little graphite "tit" is in place and in good shape. This is the contact for the rotor. If all is good there, put the cap back on and pull the coil wire at the distributor cap. Holding it about 1/2 in. from a good grounding point and have someone crank the engine. You should get a nice blue spark. If you have spark, plug the coil back in and then pull one spark plug wire at the plug and do the same. You should get the same kind of blue spark. If all is good there, check for fuel, too little or too much. I had a problem with the points on mine. I had put a brand new set in a while back and it fired right up. Backed it out of the garage and it stalled and wouldn't restart. A little troubleshooting discovered that the points were grounded out at all times. I put the old points back in and it fired right up. I couldn't see anything wrong with the new points, but took them back and got another set. Replaced them and it's worked fine since. You can check by hooking a dwell meter or timing light up. Then crank it over. The dwell meter should flucuate in the range of the dwell angle, unless the points are grounded out, or the timing light should flash every time the cylinder that you're hooked up to fires, unless the points are grounded out. One other thing, if the electronic module is stock, it is triggered by the points. In that case the points would normally not wear very much, except at the rubbing block where it rides on the distributor cam.

Good luck and let us know what you find out.

Last edited by mbbuff; 03-07-2010 at 08:51 PM.
mbbuff is offline  
post #3 of 3 (permalink) Old 03-09-2010, 10:07 AM
BenzWorld Member
 
dega's Avatar
 
Date registered: Mar 2010
Vehicle: W123 - 1979
Posts: 61
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Try to use another same coil to make sure if there's problem in the ignition.

W123 280 1979
W115 200 1976
W124 300E 1991
dega is offline  
Sponsored Links
Advertisement
 
Reply

  Mercedes-Benz Forum > General Mercedes-Benz Forums > Vintage Mercedes-Benz

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











  • Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
     
    Thread Tools
    Show Printable Version Show Printable Version
    Email this Page Email this Page
    Display Modes
    Linear Mode Linear Mode



    Similar Threads
    Topic Author Forum Replies Last Post
    C 250 d wont start steve e class limo W202 C-Class 4 11-02-2010 05:07 AM
    MB 250 SE - 66 idle/start problems p74 Vintage Mercedes-Benz 22 09-10-2009 07:33 AM
    71 250 Backfires doesn't start Amoosbenz Vintage Mercedes-Benz 3 04-09-2009 04:50 AM
    My 250 petrol won't start DreczlA W123 E,CE,D,CD,TD,TE Class 12 12-11-2006 08:12 AM
    250 SE 108 hard to start cold Darren 1 Vintage Mercedes-Benz 7 10-17-2005 04:07 AM

    Posting Rules  
    You may post new threads
    You may 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 Off
    Trackbacks are On
    Pingbacks are On
    Refbacks are On

     

    Title goes here

    close
    video goes here
    description goes here. Read Full Story
    For the best viewing experience please update your browser to Google Chrome