BuickCrazy Posted April 17, 2019 Share Posted April 17, 2019 (edited) I cannot get my 49 Roadmaster to fire. I replaced the coil today, but still no spark. The neg wire from the coil goes to the distributor. The positive wire goes into a black and white braided wire loom on the firewall, but I can't figure out where the positive wire goes or what it connects to. Where does the coil get its juice to fire the distributor? I have not touched any of the wiring since the last time the car ran which was several months ago. Any ideas or suggestions? Edited April 18, 2019 by BuickCrazy (see edit history) Link to comment Share on other sites More sharing options...
Pete Phillips Posted April 17, 2019 Share Posted April 17, 2019 Open the points and rub some sandpaper back and forth where they contact each other. After several months of sitting, they can be slightly glazed or even have a light coating of rust. 2 Link to comment Share on other sites More sharing options...
Pete O Posted April 17, 2019 Share Posted April 17, 2019 This is from a '50 diagram, but I can't imagine '49 is too different. Wire goes from ignition switch to the coil. Link to comment Share on other sites More sharing options...
BuickCrazy Posted April 18, 2019 Author Share Posted April 18, 2019 Pete - Thanks for the responses. Actually there is no spark from the plug wire from the coil to the center of the distributor so it appears that the spark is not getting to the distributor much less the points. Sorry I did not make that more clear. After I posted I found my 1949 Buick shop manual and found a similar diagram showing the positive coil wire going to the ignition switch. It seems to me that the coil is not getting any voltage/current. Could the ignition switch be the problem? Link to comment Share on other sites More sharing options...
JohnD1956 Posted April 18, 2019 Share Posted April 18, 2019 Have you checked if there is power at the positive terminal of the coil when the ignition switch is turned on? A volt meter would show this. And if you do have power at the terminal then either the new coil is bad, or the points are not opening to allow the coil to fire to the distributor. As I am sure you know, the coil is always powered once the switch is on. But when the points close the coil is grounded to the distributor. When the points open then the coil should ground by firing a spark to the center of the distributor cap. Did you ever check the wires going to the distributor and then inside of the distributor going to the points? Cracked, or deteriorating insulation, may be resulting in one or more of those wires grounding out continuously thus by-passing the points , causing the coil to be unable to fire. You may also have a bad condenser inside the distributor. I seem to recall several incidences of people having new coils and condensers that were bad right out of the box Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted April 18, 2019 Share Posted April 18, 2019 Randy, try connecting a jumper wire from the battery positive post to the positive {+} on the coil. Ben 1 1 Link to comment Share on other sites More sharing options...
avgwarhawk Posted April 19, 2019 Share Posted April 19, 2019 On 4/17/2019 at 9:19 PM, BuickCrazy said: Pete - Thanks for the responses. Actually there is no spark from the plug wire from the coil to the center of the distributor so it appears that the spark is not getting to the distributor much less the points. Sorry I did not make that more clear. After I posted I found my 1949 Buick shop manual and found a similar diagram showing the positive coil wire going to the ignition switch. It seems to me that the coil is not getting any voltage/current. Could the ignition switch be the problem? Ballast resistor is not burnt? Link to comment Share on other sites More sharing options...
Frank DuVal Posted April 19, 2019 Share Posted April 19, 2019 6 volt ballast resistor? They are a 12 volt part. Also, not in diagram above. On 4/17/2019 at 9:19 PM, BuickCrazy said: Actually there is no spark from the plug wire from the coil to the center of the distributor so it appears that the spark is not getting to the distributor much less the points. You have theory backwards. Points MAKE the spark the coil produces. The didtributor is two parts, the low voltage side, points and the high voltage side, the rotor and distributor cap. Totally independant, except timed together. The points power the coil and then not power the coil as they open and close, even though they are in the grounded lead of the coil, and the coil is "hot" all the time the ignition is on. When the points open, the magnetic field insisde the coil collapses, the lines of flux cut across the windings producing high voltage at the coil tower. Link to comment Share on other sites More sharing options...
Pete O Posted April 19, 2019 Share Posted April 19, 2019 Do what JohnD1956 suggested. Get a voltmeter or test light and with the ignition on, put one then the other lead on the meter on one coil post and the other to ground. Any voltage? If not, the ignition switch could be the problem. If you do have voltage, then remove the distributor cap and check if the points are opening and closing when you crank the engine. Clean the point contacts with a file and re- gap the points. Put the high voltage wire from the coil near a ground source and open and close the points with the ignition on and you should see a health spark. Link to comment Share on other sites More sharing options...
BuickCrazy Posted April 28, 2019 Author Share Posted April 28, 2019 Hey guys - Just wanted to let you know I am reading your post, but have been preoccupied with a plumbing leak under my slab ans unable to work on the car. I am going to try all the suggestions. Thanks for all your help. Randy 1 Link to comment Share on other sites More sharing options...
jackofalltrades70 Posted April 28, 2019 Share Posted April 28, 2019 5 hours ago, BuickCrazy said: Hey guys - Just wanted to let you know I am reading your post, but have been preoccupied with a plumbing leak under my slab ans unable to work on the car. I am going to try all the suggestions. Thanks for all your help. Randy Thanks for checking back in and letting us know you are reading the help given. let us know how you make out and if you need more help Matt Link to comment Share on other sites More sharing options...
BuickCrazy Posted November 3, 2019 Author Share Posted November 3, 2019 Just wanted to touch base with everyone that offered suggestions/help with my 49 Roadmaster with no spark. I finally have had some time to devote to getting the car running. I bought some emery cloth at my local parts store and and cleaned the surface of the points. When I turned on the ignition and pulled the points apart with a screwdriver I saw the spark I have not seen in months. I put the cap back on the distributor and the car fired up. After letting it warm up for a while I drove her around the block. It ran really smooth. I know I need to replace the points and condenser because my fix is only temporary, but now I know what my problem was. As a side note when I bought my first car in 1966 and for a few cars after that all of which had points I regularly changed or cleaned and adjusted my points without an issue, but I has been about 40 years since I last had to do it. I had forgotten everything I knew about points. Today I regained some of that knowledge thanks to those that replied to my post. It is a good thing because I have a 70 and 72 Riviera with the 455 in them that I think have the same issue. The first thing I am going to do with them is clean the points to see if I can get them running again. Thanks again. 2 Link to comment Share on other sites More sharing options...
Frank DuVal Posted November 4, 2019 Share Posted November 4, 2019 Actually, if the points look good, no blueing of the steel or rust, you are probably good for a long time. It is common for points to get a non-conductive coating on the contact areas and 400/600 grit wet or dry is fine to dress them to shinny conductive surface. Fold the paper in half, so a grit surface is on both sides, open the points, insert the paper, close the points, draw the paper out. Do it several times. Back 30 + years ago, a point file was a standard mechanic tool. It is an annual ritual to clean the points on my Ford 8N tractor. It sits more than it is used for cleaning the driveway. Link to comment Share on other sites More sharing options...
old-tank Posted November 4, 2019 Share Posted November 4, 2019 10 hours ago, Frank DuVal said: ack 30 + years ago, a point file was a standard mechanic tool. A point file is the tool to use. Sandpaper for emergencies only. The grit get embedded and you soon have a non conductive set again. 1 Link to comment Share on other sites More sharing options...
Frank DuVal Posted November 5, 2019 Share Posted November 5, 2019 Yes, emery paper bad. Wet or Dry 400 works good, especially wet with oil, but one should wash with contact/carburetor/brake cleaner (not enough to wash lube out of distributor parts, best do it out of the distributor) and run clean white paper between the contact points to remove oil/grit/dirt, or as Old Tank says......it will get embedded.👍 1 Link to comment Share on other sites More sharing options...
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