7-TWO-510 Posted July 3, 2012 Report Share Posted July 3, 2012 Switched from elec to new points and found the top dead center, and it turned on. a few days later had to find a bolt for the dizzy to stay in place, so i marked it and put it right back on where it was and no spark... there are a million threads but cant find one for my exact problem. Anyone got an answer?? Quote Link to comment
DanielC Posted July 3, 2012 Report Share Posted July 3, 2012 A points ignition system works like this. You turn the key on. That applies power to the ballast resistor, and then power goes to the ignition coil positive terminal. The coil negative terminal goes to the points. The points ground the coil. When the time is right for the spark plug to fire, the points open. Check for power to the coil. Check that power gets to the points, with the points open. You can do this with a test light. Quote Link to comment
ggzilla Posted July 3, 2012 Report Share Posted July 3, 2012 Most common problem is a loose wire or wire touching metal. Quote Link to comment
datzenmike Posted July 4, 2012 Report Share Posted July 4, 2012 Pull the coil wire and put an old spark plug in the end and lay on a grounded surface. Crank motor and see if there is a spark.... (sometimes in the course of troubleshooting a problem is fixed by accident. Having the plug where you can see if the spark is working or not will save time) Yes there is a spark. Now do the same thing with a plug wire. If no spark the problem is somewhere between the coil and the plug wires. Possibly the distributor cap or rotor is bad or missing. No spark. Continue on below... Get a $5 test light. It's just a 12 volt bulb with a probe on one side and an alligator clop on the other. Place the clip on any grounded point and touch the probe to the + side of the coil. With key on you should light up the bulb.... 1/ Yes the bulb lights... go down to 3/ 2/ No light. You are not getting power from the ignition switch. Perhaps fusible link is blown. 3/Place probe on negative side of coil and crank the motor. Test light should turn off and on... 4/Yes it flashes off and on... go down to 6/. 5/ No flashing on or off. Check that points are opening and closing when motor is cranked. Confirm that distributor is fully grounded. Disconnect the capacitor... if this fixes the problem replace it. 6/ flashing indicates that the coil is getting power and the points are opening and closing and the coil should be working. It's possible the coil wire to the distributor is bad so borrow one and replace it temporarily and see if this fixes the problem. If there still is no spark the coil is bad and needs replacing. Quote Link to comment
7-TWO-510 Posted July 4, 2012 Author Report Share Posted July 4, 2012 I think my biggest problem is how jig rigged the whole harness is the wires that were supposed to go to the coil are not the right ones and i have 2 possible ground wires (dont know which one is right) i am not getting power to any of the two coils that i do have and cannot get the dist. timed/aligned pointed toward the cam-head . is there a ratsun mechanic around i stay out in santa clarita. Im bout to lose my mind over this! :frantics: Quote Link to comment
Boaty Posted July 4, 2012 Report Share Posted July 4, 2012 See if you can pick up a wiring diagram from Paolo.. no idea how to get in touch with him. But probably the best wiring diagram I've ever seen. Well worth the money. Plus, makes a great placemat on the dinner table. Quote Link to comment
datzenmike Posted July 4, 2012 Report Share Posted July 4, 2012 You said it started and ran so it must be wired ok don't you think? If you don't have power to the coil how do you know this? Did you use a test light? Pull the coil wire and put an old spark plug in the end and lay on a grounded surface. Crank motor and see if there is a spark.... (sometimes in the course of troubleshooting a problem is fixed by accident. Having the plug where you can see if the spark is working or not will save time) Yes there is a spark. Now do the same thing with a plug wire. If no spark the problem is somewhere between the coil and the plug wires. Possibly the distributor cap or rotor is bad or missing. No spark. Continue on below... Get a $5 test light. It's just a 12 volt bulb with a probe on one side and an alligator clop on the other. Place the clip on any grounded point and touch the probe to the + side of the coil. With key on you should light up the bulb.... 1/ Yes the bulb lights... go down to 3/ 2/ No light. You are not getting power from the ignition switch. Perhaps fusible link is blown. 3/Place probe on negative side of coil and crank the motor. Test light should turn off and on... 4/Yes it flashes off and on... go down to 6/. 5/ No flashing on or off. Check that points are opening and closing when motor is cranked. Confirm that distributor is fully grounded. Disconnect the capacitor... if this fixes the problem replace it. 6/ flashing indicates that the coil is getting power and the points are opening and closing and the coil should be working. It's possible the coil wire to the distributor is bad so borrow one and replace it temporarily and see if this fixes the problem. If there still is no spark the coil is bad and needs replacing. Quote Link to comment
LenRobertson Posted July 5, 2012 Report Share Posted July 5, 2012 Since you have a '72, the original wiring harness is probably for a dual-points dizzy. So whether or not you are running a dual-points, you may have two neg. wires from your harness for the two sets of points. My not very readable Chilton's wiring diagram shows a "Relay" (not the "Starter Relay", that is shown as a separate item), "Third Gear Switch", and "Carburetor Switch". Once upon a time I understood how all this worked to (I think) switch from one set of point to the other, but it is all hazy to me this afternoon. I believe one of those Switches, or maybe the Relay, is that box with a plastic cover mounted on the engine side of the firewall above the throttle linkage. Maybe none of this has any bearing on your lack of power to the coil, but possibly it does. Or maybe a previous owner has removed all this junk and bypassed the wiring to it. I'm hoping someone who understands the dual-points wiring will chime in here with info for you. If you don't have power to your coil when the key is On, you need to trace between the two to find where the disconnect is. Len Quote Link to comment
banzai510(hainz) Posted July 7, 2012 Report Share Posted July 7, 2012 Why would one go backwards to a point dizzy? use a point coil and ballast resisitor!!!!!!!!!! theres a bacic wire diagram on here . Blk whit wire to the ballast resisitor and blk/grn hooks up to the other end of ballst resstor a Blk/Blu hooks up to the coil. if dua point dizzy use the side with the big capicitor. PS if not spark upi even see if the points are opening. Pull center wire from the dizzy and place near ground. it should spark. Points are either grounded or wire grounded. ck to see 12volt with key on at the blk white wire.If not ck the fuse box/fuse or clean Quote Link to comment
ggzilla Posted July 8, 2012 Report Share Posted July 8, 2012 Yes that's a downgrade. But L18 came with points orginally. A new points set (which includes the all-important condensor) will make it like new. Quote Link to comment
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