‘67.5 R16 Not Firing - Ignition Electrics?
Posted: Thu Jun 18, 2020 10:48 am
Reaching out separately from thread that was getting too broad on inop issues.
I followed the 2 schematics provided by Curtis to the letter. Thanks. Since I had recently acquired the car it was running just rough intermittently. I decided to replace all the ignition system components as a tune-up as I don’t know when they were done last nor did seller AND eliminate those items as contributory to the misfire condition. So prior to cleaning grounds and replacing points, condenser and coil, the car was starting. Took pictures of connections prior to taking stuff apart. After reassembly car just spins over but won’t come close to starting. Since initial replacement of those parts I also put new NGK plug wires on and installed another new coil for a points ignition system-still no starting. Ordered new rotor button but wrong one sent (would not fit distributor shaft) so scuffed end of old one that points to cylinders and re-used. There was a question on whether other new coil with 40k volts output was appropriate for ignition sys with points.
My multimeter was acting funny reading voltage, so I used my Test light. You clip it on a ground and the body lights up when the pointed end touches something that is 12 volts positive OR you can reverse connections to test for Ground conditions. It is pointed to pierce wire insulation to test for voltage at a junction in a harness etc.
So I tested the wires per schematic coming out of firewall to ballast resistor, coil and distributor when the key was turned to Start on the ignition switch and those wires tested hot. Hot across ballast, coil and wire that connects to side of distributor where condenser wire connects on outside and points wire connects on other side (inside the distributor cap). I was able to measure 7.2 volts on side of ballast that connects to positive side of coil. Also observed, with ignition switch turned to Start, the test light lit up bright on side of ballast with connection of Black/white wire. When I touched the other side (connecting to Positive side of coil) that post was lit significantly dimmer, which supported ballast working, stepping voltage down to 8 volts (7.2).
The thing that is concerning or maybe working as designed- The whole distributor test negative when I reverse the connections on Test light to measure for Grounds. The points plate, points, connection where condenser/points pigtail and Black wire from firewall terminates. Also never saw points arc when rotated to open (on lobe). When tested with Test light for hot condition at the points neither side lit the light. Also placing #1 spark plug on valve cover and spinning motor over, there is no arc across gap.
Should the distributor be grounded out and is that preventing no voltage to points or spark plugs?
In cleaning all the surfaces for better ground, removing paint on firewall where coil mounting bracket secures. have I introduced a Ground condition that is shorting out the distributor?
There appear to be 4 connections that were removed in replacing ignition parts that for some reason are not supporting firing now. Black and Black/white wires out of firewall to Ballast and Negative terminal on coil. Wire from out of Ballast to Positive side of coil. Black wire from firewall to distributor where condenser wire, points pigtail terminates.
Related: Fuse box connections cleaned, fuses replaced, correct Amperage confirmed and location in order. Battery voltage at 12.4 with everything off. Headlights, fog lights and running lights come on. Cleaned and re-gapped spark plugs at 0.029 in. Points gap set at 0.020 in.
I followed the 2 schematics provided by Curtis to the letter. Thanks. Since I had recently acquired the car it was running just rough intermittently. I decided to replace all the ignition system components as a tune-up as I don’t know when they were done last nor did seller AND eliminate those items as contributory to the misfire condition. So prior to cleaning grounds and replacing points, condenser and coil, the car was starting. Took pictures of connections prior to taking stuff apart. After reassembly car just spins over but won’t come close to starting. Since initial replacement of those parts I also put new NGK plug wires on and installed another new coil for a points ignition system-still no starting. Ordered new rotor button but wrong one sent (would not fit distributor shaft) so scuffed end of old one that points to cylinders and re-used. There was a question on whether other new coil with 40k volts output was appropriate for ignition sys with points.
My multimeter was acting funny reading voltage, so I used my Test light. You clip it on a ground and the body lights up when the pointed end touches something that is 12 volts positive OR you can reverse connections to test for Ground conditions. It is pointed to pierce wire insulation to test for voltage at a junction in a harness etc.
So I tested the wires per schematic coming out of firewall to ballast resistor, coil and distributor when the key was turned to Start on the ignition switch and those wires tested hot. Hot across ballast, coil and wire that connects to side of distributor where condenser wire connects on outside and points wire connects on other side (inside the distributor cap). I was able to measure 7.2 volts on side of ballast that connects to positive side of coil. Also observed, with ignition switch turned to Start, the test light lit up bright on side of ballast with connection of Black/white wire. When I touched the other side (connecting to Positive side of coil) that post was lit significantly dimmer, which supported ballast working, stepping voltage down to 8 volts (7.2).
The thing that is concerning or maybe working as designed- The whole distributor test negative when I reverse the connections on Test light to measure for Grounds. The points plate, points, connection where condenser/points pigtail and Black wire from firewall terminates. Also never saw points arc when rotated to open (on lobe). When tested with Test light for hot condition at the points neither side lit the light. Also placing #1 spark plug on valve cover and spinning motor over, there is no arc across gap.
Should the distributor be grounded out and is that preventing no voltage to points or spark plugs?
In cleaning all the surfaces for better ground, removing paint on firewall where coil mounting bracket secures. have I introduced a Ground condition that is shorting out the distributor?
There appear to be 4 connections that were removed in replacing ignition parts that for some reason are not supporting firing now. Black and Black/white wires out of firewall to Ballast and Negative terminal on coil. Wire from out of Ballast to Positive side of coil. Black wire from firewall to distributor where condenser wire, points pigtail terminates.
Related: Fuse box connections cleaned, fuses replaced, correct Amperage confirmed and location in order. Battery voltage at 12.4 with everything off. Headlights, fog lights and running lights come on. Cleaned and re-gapped spark plugs at 0.029 in. Points gap set at 0.020 in.