Triumph Repair: random engine quit, bright sunny day, intermittent problems

Question
Howard; My 65 TR4 usually runs beautifully, very occasionally, when starting from a stop,it will sputter and release a cloud of smoke from the exhaust. ( I'm thinking unburnt fuel from lack of spark ?) Recently, it began to exhibit another symptom, which I realize may not be related. It will suddenly die, as though switched-off. If I wait a minute or two and then turn it over a few times it will start, it might die again in a couple of minutes (usually)  or it may be just fine for the rest of the trip. It does have a Pertronix El. Ign. The first problem has been around much longer than the second one and has been much lees frequent. Hope you have some suggestions. Thanks,     Steve

Answer
Hi Steve,

Intermittent problems like that were a hassle to correct because most of the time it is ok when testing so I worked out a method to diagnose such problems and it worked every time.

Most mechanics will agree that the easiest car to fix is one that don't run and the hardest one to fix is one that don't run occasionally.

So what I worked out is simple, Just take a timing light and tape the trigger down and connect it to the coil wire (not a plug wire) and put the light under a wiper arm so you can see the flash of the light when driving. (if it is a bright sunny day you may have to tap a piece of cardboard on the windshield over the end of the light so you can see the flash when driving.

If when you are driving it dies or even cuts off for just a second or so or even sputters you will be able to see the blink or cut off of the light. This tests the primary of the ignition system. (igniter, wiring and primary and secondary of the coil) (unlikely that cap, rotor or plugs or plug wires can do that)

If the flash is continuous all the way to the stop of the engine then it is not ignition. So you must see fuel.

You can see fuel pressure to the carburetors by putting a "T" in the fuel line close to the carbs and run a long hose out from under the hood and put it under a wiper arm like the ignition test. (be sure to put clamps on all hose connections) You want to see from 1.5 PSI to about 3 PSI at all times the engine is running. If you see the pressure drop just before the engine dies you know it is fuel supply causing the problems. (pump, lines, or tank)

Pertronix is an aftermarket igniter often used to replace the original system (points and condenser and even used on later model Triumphs and MGs to replace the Lucas/Opus igniters. I personally did not like to replace a pointed ignition system with electronic for street use. To me the disadvantages far out weigh the advantages.

If you have the man who designed the electronic ignition system in the car with you out in the country and it dies, You nor him can fix it. If I am out in the same road and my points system causes my engine to die, There is a 99% chance I can fix it with just a few hand tools and drive on. OR I can keep a spare set of points and condenser in my glove box for just a few bucks. The Electronic ignition systems are too expensive for me to just carry an extra in the glove box and NO one can say one lasts longer then the other which I seen in the years I worked in dealerships.

Howard