MG Car Repair: 1977 mgb 1800, logic probe, secondary ignition

Question
I have owned this car for 17 years and has been run every year since. I have always had a pop in the exhaust. I recently installed a after market intake and carb a Weber 32/36. The problem still exists, but when I richen the mixture it is less noticeable in the popping but the unburned fuel really smells. I put on new points cap rotor wires plugs. I did connect my timing light on the coil wire and every once in a while it will not spark. Could this be the coil all this time?

Answer
Paul, a loss of your timing light flash could mean a coil but it could also be anything in the ignition system so tests are needed to tell what was the cause. I doubt you still have the original Opus Lucas system so you need to monitor the primary circuit. You need access to a scope or you can get a Logic Probe or any LED test light. You can get a Logic Probe from most electronic stores like Radio Shack. This will give you a flashing light of the triggering of the coil to at least tell you if it is the electronic unit or the coil. With a Probe you monitor the negative side of the coil. With a Logic Probe you will be monitoring a alternating red an green flashing of the Probe.
The most sure way is to have it put on a scope so you can look at the pattern of the primary and the secondary ignition.
Popping in the exhaust can come from a leak in the exhaust or incorrect timing too.
Howard