apparent dead ignition on G, John T, anyone??

just returned from trying to start my G w/ electronic ignition and 55kV coil. It lit quickly as usual but as I got off to close the compression reliefs, I heard the flywheel side cylinder go quiet. No fire from the relief. I closed the other ( at the time, hot) side, got on the tractor and thought that as soon as I put a little load on it, the cold side would come about. It moved about 10', then the one firing cylinder went south. As it shut down, there was an audible pop from what seemed to be the distributor and coil area. Totally dead now, both sides. The ignition system was installed about 8 months ago and has performed flawlessly, till now. To add detail, I have made no changes to the ignition system between the last time the tractor ran (less than a month ago), nor did a quick inspection reveal any obviously external issues like a loose or flawed wire.

I know nothing about diagnosing the coil; would a continuity check tell me anything, should I look for a loose or defective wire between the resistor and coil (or elsewhere) or do I need to just remove the system and send the whole thing back to Denny's? If it had just died and had the exhaust backfire or just quietly shut down, I would suspect a wire thing but the pop makes me think coil.

Your collective help would be appreciated.

Thanks,
Rob

Thanks for the pointers. Yes, there was definitely a 10-second or so period where the tractor ran on one cylinder which, I agree, seems weird if the Petronix is the culprit. Given the events of the past week for me, this is just one more strange, not particularly desirable, occurrence. I have the Denny's high-output 55kV coil that was supposed to be a perfect match with the Petronix. They sent me the coil, the resistor, their plug wires and the Petronix with detailed instructions on how to wire in a 12V negative ground unit. No doubt I could have goofed somewhere but the instructions were pretty explicit. Is it possible that the setup could have run perfectly well for 8 months, then all of a sudden croaked due to it initially being miswired??

As soon as we get out of the deep freeze here in Illinois, I will head to the barn to take a quick shot at diagnostics and inspection.

Your continued input and guidance is appreciated.

Thanks,
Rob

First, you mentioned "resistor" usually with an elec switch you toss any old Ballast Resistors (which fed a stock 6 volt coil) and use a new internally ballasted full 12 volt high performance coil. If it has a Ballast and a 6 volt coil, the Ballast or its wiring could have went bad/open. The Ballast is series between the Ignitions switches IGN terminal and the Coils high input terminal. If its open, the coil or switch gets no voltage and wont work (see below)

Heres some basics you need to make her work, regardless if points or an elec switch. Use a simpe test lamp and:::

1) Turn the Ignition ON and you MUST HAVE Voltage present on the Coils high input (from switch NOT to distributor) terminal. It powers the Coil and feeds the elec switch. If theres no voltage on the coils high input terminal, the problem may be a bad switch or an open wire from switches IGN output terminal down to Coil, or an open Ballast (if it has one). No kind of coil Ignition (points or elec switch) is ever gonna work until you power up the coils high input side when the Ignition is ON (Check this first)

2) Once you have voltage on the coils high side input, turn the Ign ON and crank the engine over. Place the test lamp over on the other coil terminal and as cranked it should flash ON and OFF there. If it never flashes ON, the coils primary winding (between lil + and - terminals) may be bad/open,,,,, ,,,,, or the elec switch is bad/dead shorted,,,, or some wires from coil to elec switch or where it feeds thru distributor housing??? (check those wires) are dead shorted. If it never flashes OFF, the elec switch is bad or wires are open between coil and switch, or the switch is baddddd ddd. You can do a preliminary coil resistance check to insure its not open, its low voltage primary (between + and -) should be from around 1.5 to 3 ohms, while its high voltage primary between one of the lil terminals and the high voltage tower output, should be several thousand ohms.

If the coil is good,,,,, ,,,coil has power when Ignition is ON,,,,, ,,and theres no open wires or shorts (especially where wires feed into distributor),,,,, ,,,,Im feared the elec. switch may be baddddd ddddd d. As Bob noted, reverse polarity can wreak havoc on them critters.

Lemme know, Good Luck

John T in Indiana

Many thanks for the help. The batteries have not been changed out or discharged, so unless someone's sabotaged my ride, the original negative ground polarity should be intact. John, the resistor I installed in series came directly from Denny's as an integral part of their coil/electronic ignition package. It is indeed a 12V system.

I don't have a test lamp; I'll have to purchase one. I would guess any reputable auto parts supply would have one. I do have a VOM so I can at least address resistance and steady-state voltage test issues quickly.

John, you mention the "electric switch"; Are you are referring to the ignition switch or the electronic ignition module in the distributor? I assume you're thinking it is the module in the distributor and this would regrettably correspond to the "pop"

It's supposed to get a bit chilly here over the next 36 hours or so so it might be a day or so before I resolve this.

I will post the results on however this gets resolved.

Again, Thanks a Ton!!!

Rob

Reversed battery ground polarity is the quickest way to "KILL" the electronic ignition.

If the original misfire was caused by a problem (loose or defective high tension wire to that plug, for example), the module could have been damaged. Problems in the high-tension circuit are tough on electronic ignition modules.

And, yes, the Pertronix (I assume that's what you have) electronic ignition units will "POP" if they are damaged, or the coil is shorted. (Don' ask how I know this! ($$$$) Coils will "POP" also, if shorted or overheated.

Also, don't overlook any possible mechanical damage to the distributor or it's drive.

If the original misfire was caused by a problem (loose or defective high tension wire to that plug, for example), the module could have been damaged. Problems in the high-tension circuit are tough on electronic ignition modules.

And, yes, the Pertronix (I assume that's what you have) electronic ignition units will "POP" if they are damaged, or the coil is shorted. (Don' ask how I know this! ($$$$) Coils will "POP" also, if shorted or overheated.

Also, don't overlook any possible mechanical damage to the distributor or it's drive.