Coil Issues

[SPORT]

Chasing a miss/hesitation with my Gen I bike anything off of idle during cruise or free rev. Dealer thinks it may be a coil. I noticed while doing a TBS that VERY infrequently during idle the bike would momentarily stumble and the #2 cyl. (as shown on the manometer ) would drop, then rise back up to normal operation.

Could I have a coil and/or coil wire giving out?

 

[ionbeam]

One coil fires plugs 1 & 4; the other fires plugs 2 & 3. I would expect a bad coil to misfire both plugs. Consider the plug wire or the resistor in the cap. Don't rule out a plug that is internally damaged. It could also be the injector.

 

[Bungie]

Also while your in there. Check the main bulk head connector behind the steering stem for corrosion.

 

[SPORT]

Ionbeam & Bungie,

Thank for the insight, and I haven't ruled them out.

However, Considering the dealers advice I removed the right lower cowling to access the coils, ran the bike to operating temps and began spraying the colis, coil wires and spark plug housing. It seemed the miss was more prevelant, though still intermittent, when I poked around the coil wires from the coil through the underside of the bike frame.

I would like to see if I can swap the two coils and plug wires to see if the problem travels from the #2 cyl to the #1 cylinder.

As a note, I replaced the spark plugs less than 500 miles ago because of this issue, and it did not relieve the problem.

This all started HERE and HERE.

 

[03HiYoSilver]

Sport,

You could trim back the offending spark plug wire and re-insert the Spark Plug Cap.

In my case where #4 cylinder was fouling out, it turned out to be the Throttle Body Assembly.

Hope this helps.

 

[Zorlac]

"and began spraying the colis, coil wires and spark plug housing. "

With what?

"I would like to see if I can swap the two coils and plug wires to see if the problem travels from the #2 cyl to the #1 cylinder."

It's a wasted spark system, a coil fires a pair of plugs at the same time, +1 on Ionbeam's input.

Maybe just treat yourself to some Iridiums, to rule out the plugs altogether.

 

[Geezer]

Are you spraying with WD40? If so then that implies wet wires. WD40 displaces the water and stops the spark from leaking out through the wet insulation. I solved a wet wire problem on my Maxim by coating the wires with high temp silicon.

 

[wfooshee]

I had a miss on #4, and a fouled plug which came back within a couple weeks of changing plugs. Eventually I found some residue (gray dusty-looking crud) on the #4 wire where it exited the coil. Replaced that coil and things got much better.

That wasn't all there was, as I still have a very occasional miss, and my mileage is not what it should be, but that new coil helped tremendously.

The most common point of ignition trouble on these bikes, though, is the wire into the plug cap. The cap just screws onto the plug wire, has a little pin that pierces long-ways into the end of the conductor. Kind of like a wire nut, but inside out. Corrosion there will kill your spark.

To remove the cap from the wire, just hold the wire near the cap and turn the cap like you were taking a nut off of a bolt. If you find corrosion in the end of the wire, just cut it back a quarter inch or half inch, clean the pin in the cap, and fasten it back on.

 

[SPORT]

"and began spraying the colis, coil wires and spark plug housing. "
With what?

Water.

"I would like to see if I can swap the two coils and plug wires to see if the problem travels from the #2 cyl to the #1 cylinder."
It's a wasted spark system, a coil fires a pair of plugs at the same time, +1 on Ionbeam's input.

Maybe just treat yourself to some Iridiums, to rule out the plugs altogether.

I understand Ionbeams point. As such, I've ruled out a bad coil only because it's cyl. #2 that has the issue. If it were a coil, both 2 & 3 would have the miss. But it could be a plug wire; thus, swapping coils & wires (while keeping the same firing order) should transfer the miss to cylinder #1.

Are you spraying with WD40? If so then that implies wet wires. WD40 displaces the water and stops the spark from leaking out through the wet insulation. I solved a wet wire problem on my Maxim by coating the wires with high temp silicon.

WD40 has a histroy of drying out rubber over time. why would anyone use it to check for a faulty coil wire?

As stated earlier, I've replaced the spark plugs less than 500 miles ago (with Iridium) and the problem persists. This issue has been a headache ever since I had the TPS recalled two months ago. The TPS has been extensively and repeatedly checked to make sure it is not at fault.

I have also had the ECU connectors under the 'T' brace separated, cleaned, Di-electric grease applied and reconnected 4 times, but this has not caused a change in engine performance.

One other insight I've fobserved. 1/2 hr after shutting the bike down while observing the #2 cylinder 'hick-up' intermittently I ran the bike again. This time it did not hick-up once. The only problem that remained consistant was the mild miss in the engine anytime it was off of idle. It was mentined that the ECU may be going...

 

[SPORT]

I had a miss on #4, and a fouled plug which came back within a couple weeks of changing plugs. Eventually I found some residue (gray dusty-looking crud) on the #4 wire where it exited the coil. Replaced that coil and things got much better.
That wasn't all there was, as I still have a very occasional miss, and my mileage is not what it should be, but that new coil helped tremendously.

The most common point of ignition trouble on these bikes, though, is the wire into the plug cap. The cap just screws onto the plug wire, has a little pin that pierces long-ways into the end of the conductor. Kind of like a wire nut, but inside out. Corrosion there will kill your spark.

To remove the cap from the wire, just hold the wire near the cap and turn the cap like you were taking a nut off of a bolt. If you find corrosion in the end of the wire, just cut it back a quarter inch or half inch, clean the pin in the cap, and fasten it back on.

Something worth looking into.

Thanks

 

[SPORT]

...it turned out to be the Throttle Body Assembly.

Would you care to elaborate?

What exactly was wrong with the TB and what was done to fix it?

 

[Zorlac]

I don't really understand the logic behind spraying water on high voltage wires carrying 20Kv plus, maybe it's an accepted way, I've just never heard of it.

You can check the plug wires for continuity with an ohmmeter when you get them off and you can look for flashes of corona off the plug wire in the dark when it starts missing.

 

[SPORT]

I don't really understand the logic behind spraying water on high voltage wires carrying 20Kv plus, maybe it's an accepted way, I've just never heard of it.You can check the plug wires for continuity with an ohmmeter when you get them off and you can look for flashes of corona off the plug wire in the dark when it starts missing.

It's a fairly common practice within the automotive industry. All's it does is help induce a short, if there is one. No harm done, but can assist in finding potential weaknesses in the coil/wire system.

 

[wfooshee]

Or once the short is induced, you burn through the insulation and now it's a permanent condition. Deosn't make sense to me, either.

As for swapping the coils with each other, perfectly feasable in concept, but the non-removable plug wires are enough different lenghts that I don't think they can be made to reach the other plugs, i.e. 1 to 2, 2 to 1, 3 to 4, 4 to 3, then reverse the trigger wires on the coils. But then if the problem moves you don't really know if it followed the coil or the wire. If it doesn't move, you know you have a problem in the cylinder, maybe the plug, maybe the throttle body, maybe the injector.

 

[SPORT]

Post #82 of this link shows the cure to my wowes.

Thanks for the suggestions

 

[yamaholic]

Yes, the #2 and 4 cyl coil gave up the ghost on my 03 at about 3K miles!

Missing/hesitation was the symptom. I suspected the coil was bad; dealer repalced it under warranty. No problems since.

I consider it an anomoly as I don't recall reading others complaints about it. Probably just got the one out of 10,000 bad ones...