Posted this question in another forum but could really use some help so posting here also. Hope that's alright.
Car is 1967 Mustang with 200 six. Stock ignition. Coil, points, condenser, cap, rotor, wires, spark plugs are new. Just rebuilt carb and played with different float settings. Confirmed valve seals are good. Confirmed wires are correct on coil. Cleaned all ground points. Compression test shows 185 to 190 all cylinders. Dwell stays steady at 38. Timing is good.
Issue is car will foul out plugs in about 10 miles of driving. Also have pop pop pop in mufflers on deceleration. Probably from unburned fuel igniting in mufflers.
My car is having a weak spark. When I hold the coil wire off the block and crank engine the spark is a thin line of yellow. I have done this test before while chasing another issue and it was a fat blue spark. I found an old post of mine where I mention that.
I have an Actron dwell / rpm / volt meter.
Followed the instructions and hooked black to chassis ground & green to the - side of the coil terminal that runs to distributor.
When I fired up the car it was cold and showed nearly 7 volts with the needle fluctuating some. As it warmed up the volts dropped to 6 volts and would sometimes go slightly below 6. The needle continued to fluctuating some. The volts increased a lot when I revved the engine.
Should this be a steady number? This is what provides juice to the points right?
Would a bad alternator or voltage regulator cause weak spark? The voltage needle on the dash moves back and forth some and the headlights flicker some (get brighter dimmer over and over) too. Similar to how the volts fluctuate.
Really appreciate any advice. Will do any test that can be recommend right away. Have regular volt meter too.
Car is 1967 Mustang with 200 six. Stock ignition. Coil, points, condenser, cap, rotor, wires, spark plugs are new. Just rebuilt carb and played with different float settings. Confirmed valve seals are good. Confirmed wires are correct on coil. Cleaned all ground points. Compression test shows 185 to 190 all cylinders. Dwell stays steady at 38. Timing is good.
Issue is car will foul out plugs in about 10 miles of driving. Also have pop pop pop in mufflers on deceleration. Probably from unburned fuel igniting in mufflers.
My car is having a weak spark. When I hold the coil wire off the block and crank engine the spark is a thin line of yellow. I have done this test before while chasing another issue and it was a fat blue spark. I found an old post of mine where I mention that.
I have an Actron dwell / rpm / volt meter.
Followed the instructions and hooked black to chassis ground & green to the - side of the coil terminal that runs to distributor.
When I fired up the car it was cold and showed nearly 7 volts with the needle fluctuating some. As it warmed up the volts dropped to 6 volts and would sometimes go slightly below 6. The needle continued to fluctuating some. The volts increased a lot when I revved the engine.
Should this be a steady number? This is what provides juice to the points right?
Would a bad alternator or voltage regulator cause weak spark? The voltage needle on the dash moves back and forth some and the headlights flicker some (get brighter dimmer over and over) too. Similar to how the volts fluctuate.
Really appreciate any advice. Will do any test that can be recommend right away. Have regular volt meter too.