After 12,000 miles, one of my cylinders stops firing 500 miles from home.

[Guest]

Hi everyone,

I experienced this issue once before, and it was solved by replacing the ignition coils. 8,000 miles later (and only 500 from home) it has popped up once again, on my nearly new Dynatek coils no less...

The issue: a cylinder (2 or 3, whichever has the bad wire) not firing. It follows the plug wire to whichever cylinder I put it on, and switching the plug caps didn't make a difference. When I check spark it seems to be there, but I remember that last time this happened I had spark but it was weak/intermittent.

I've tried reconnecting the high voltage wires to the coils, and reconnecting the caps to the ignition wires. I've replaced all spark plugs.

Im not sure what else to do here. I'm stumped. Suggestions would be appreciated. It's pouring down rain. I've bunkered in a cheap motel for the night, and am seriously contemplating driving the last 500 miles on 3 cylinders. I can drive, but it is slow going. Would this do irreparable damage to my engine? I could swap the wires as I go to make things a bit more even.

[OldVet66]

Is it following the wire or the cap and did you trim the wire back a little and screw the cap back on? There is a resistor in the cap that can be accessed I believe and they can fail also. I don't think you want to wash the cylinder with unburned gas for 500 miles.

[chuck hahn]

I always automatically eliminate the resistors. get some 1/8 inch brass, or copper rod and cut it the length of the resitors and out the caps back together. Flat tip screw driver and unscrew the connector inside the cap and dump the contents into your hand.

Note that 1 and 4 don not have a spring in the caps....2 and 3 do. Put the spring in 2 and 3 first then the rod. Screw in the connector and be done with resistors.

[klylor10]

Well I'll be damned.

I sat down to systematically test whether the wire or cap was the culprit. I let the pipes go completely cold and then ran it, pipe #2 was still ice cold while the others warmed. I let them all cool again, swapped the 2+3 wire (not doing anything with the caps yet) and fired it up to test again. This time, all 4 pipes got hot. I let them cool again, and took it for a test ride. Things seem to be working, but I'm worried. I've definitely done this swap before, and it didn't work then, so I'm fearful of it just being temporary. Maybe it will be enough to get home.

One possibility: this problem started 40 miles into the first rainy day I've had in a while. I noticed that water coming off the front fender was sneaking up into the ignition coils. Has anyone experienced this causing problems before? Any ideas for preventing them getting wet again? Unfortunately the forecast is showers for the next 500 miles...

[chuck hahn]

Stop at an auto parts store and get some 100% silicone spray..about 3 bucks a can. Soak the wires and where the wires go into the caps. leave them wet and let the silicone soak in. This will make them repell any water and moisture. May cure the problem. My 98 Honda shadow would stutter and loose power in rain. Stop and let it idle and the engine heat dry the wires and it would be ok for a while.

[OldVet66]

My initial thought was why are you using caps to begin with on Dyna coils, but it wouldn't have helped. I use Dyna 8mm suppression wire, they have rubber boots, are not expensive and are no problem in the rain. You won't notice the difference except it eliminates a failure point. I had my rounds with caps and decided they were not worth the problem.

[WolfworksCustoms]

Another issue that can cause this is a stuck float....since most of the Suzis go either 4 into 2 or 4 into 1 tough to diagnose....but heres an easy way....remove the muffs....take a paper towel and wipe the inside of each header pipe....if one is wet or blacker than the other, youve isolated your problem cyl......

I have a similar issue with my VN700....one float sticks a little (seafoam and backblowing doesnt help anymore)....what i do now is just tap on tha carb in question until I hear the idle change...ergo, stuck float....
I know its tougher on inline multiples to do that than on a Vtwin....but can still be done....long screwdriver....soft end touchin the carb....tap a lil with a hammer....should at least isolate your issue.....

Im assuming too, that youve removed each plug and checked its condition, cleaned then reinstalled....thats actually the first thing to do to isolate a problem cyl....

Ine time....float on my Bessie was so bad, i ran home 10 miles on 1 cyl....not a good thing to do on an older motor btw, because on the no firing, gas will seep down past the rings into the crankcase.....a little is ok...a lot is a seriously bad thing....

[klylor10]

The issue seems to be in the ignition coils, thankfully not in the carbs. I couldn't find any silicone spray, but I got a big tube of silicone grease and coated all connection points (caps to plug, cap to wire, wire to coil). I'm only 60 miles from home and everything seems to be working great. Fingers crossed for the ride today.

I'm guessing there was an intermittent connection somewhere that may have been exacerbated by water.

Thanks for all the help.