Re: bad trigger
Not knowing what motor we're talking about here, the symptoms are that the cylinder does not fire or fires intermittently. In some cases the trigger supplies about 3 volts to the switch box which triggers the switch to discharge it's stored voltage to the coil, that in turn fires the coil which fires the spark plug.. That's layman and all you need to know unless your completely engrossed the operation of the switch boxes.
On some motors the trigger is under the flywheel and there are two magnets at the center of the flywheel hub. These magnet rings are placed one on top of the other and their poles are 180 degress opposite. In a 6 cylinder engine of this style, during the first 180 degrees, trigger coils 1,2,3, fire the first switch box via the first group of wires from the trigger and depending on the firing order they fire the coils. On the second 180, trigger coils 1,2,3 fire the second switch box via the second group of wires from the trigger coils. Now that said, the coils can be wired to the switch boxes in any order necessary to accomodate the firing order of the engine but the coils are always mounted in the logical cylinder order. This helps to elimnate confusion when putting the plug wires on the plugs.
From that you can see that if you had a 6 cylinder engine with a firing order of 153624 then trigger coil #3 would be your culprit because it provides the 3 volts to switch the switchbox of cylinders 3 # 4.
It looks like this
1 5 3 (cylinders)
1 2 3 (Trigger coils on first 180 deg)
1 2 3 (Tigger coils on second 180 deg)
6 2 4 (cylinders)
In this example you can see that cylinders 3 & 4 share the same trigger coil #3. If #3 trigger coil is faulty, then cylinders 3 and 4 would be giving you problems.
This is just an example and may not exactly apply to your engine because I don't know what engine you have. Maybe this anwser your question though.
