Easiest way to find bad SP wire.

[max49]

Hey guys , I am healing a broken femur, at home alone, but still get very bored. I have a burnt plug wire and unlike how I fixed it before from the wheel well, I am operating from the doghouse. #5 is the plug that normaly gives me trouble but I'm not positive. I'd like to find the bad one without possibly damaging them by pulling each wire off at the plug.
With the doghouse open I started the engine, I could not really hear a miss. I can generaly hear it better at the exhaust but that's too much moving around for me now.
So I pulled off #5 wire at the coil ? end, not at the SP. I restated the engine to see if I could hear a difference. I could hear a difference alright, sparks were jumping 2 or 3" from the coil (or whatever it is) to the wire. Does this mean my problem is not that wire? Or would there still be spark at that end even if the wire was dead at the spark plug end?
Any one know of a better way to check which wire is dead?

Thanks , Max

[dsbike]

You will need to have the wire connected at the coil end. The coil produces the spark. Take the wire off the spark plug, but unless it is completely broken & seperated a few inches internally in the wire you will still have spark. The problem most likely when you have a bad SP wire is that it is breaking down & the spark is migrating out through the insulation. One way to check this is have the engine running in the dark to see if there is any stray sparks out to any metal. Again not easy to see unless the wire insulation is very well worn.

If when you remove the wire from the SP end & do not notice any difference in the motor sound then this is most likely your weak wire. Try swapping this wire with another. You must move both ends of the wire to its respective coil & spark plug. In other words you can not take the wire attached to #7 coil & remove from the SP #7 & attach it to #5 sp with out moving it from the #7 coil & installing it on the #5 coil. Then do the same with #5 wire , move it to the #7 position. You must use 2 wires that will fit both positions. Now if #7 has the miss, you found your bad wire. If the miss stays with #5 then you need a new spark plug/or clean & regap it.

One more word to the wise, if you have one bad wire you probably have more that just aren't showing up yet. Replace them all. I would assume you only notice this miss under a load, I would replace all spark plugs & wires & if they are new , then I would try a different brand.

After rereading your post, I assume you have a newer engine without a distributor. You have coil packs. This is still the diagnosis for coil pack or distributor & coil. The computor takes the place of the distibutor.

[DriVer]

Max, Observing your plug wires in the dark is a valid suggestion. We have seen other members describe the same process and they were successful in picking out the bad wire.

[max49]

Thanks for the tips Driver and DS Bike. My wires are the Taylor 409's, 10.4 MM and are only a little over 6 mo old, so I wouldn't think I need to change the whole set. Maybe my best bet is waiting and looking at it at night. I'll try that next. I was confused when I pulled my first suspect, #5 at the coil and sparks were just flying. I wanted to make sure that just because it was sparking at the coil end, that , that did'nt eliminate it as the bad wire, Sounds like it does'nt.
DS Bike, is that "Dual Sport Bike" ? I have a couple of those.

[RottenRalph]

Altought I've never confirmed this, you might try using a IR temp gun at each cylinder to determin which is cooler.

[dsbike]

Max, dsbike stands for Dan Sees bike (road bicycle). I tend to ride 1000-2000 miles a year. I use the same user name for just about every internet application. Hope you find your engine miss.

[max49]

That might be a good idea ,Rotten Ralph for the next time but mine turned out to be easy to find. When I pulled on the 1st suspected #5 plug wire, at the plug, the fairly high dollar 10.4 MM , Taylor 409 boot just pulled in half. I realized it would be easier to get the other half out from the wheel well, but then the Power Gear Jacks think I don't have the parking brake on so the jacks are useless. Any body have any ideas? The Autopark is working fine including the red indicator light on the dash.
I think they just put all these stupid so called safety devices in just to make life more difficult for us and keep the RV service depts booked for months in advance. I pulled and tested every fuse under the dash and they're all good.
There are only 4 wires going to the jack control panel. Blue ,Black Red and White. Anyone know which ones to jump across to make the "Engage Parking Brake" light go off?

[DriVer]

Quote:

Originally Posted by max49 There are only 4 wires going to the jack control panel. Blue ,Black Red and White. Anyone know which ones to jump across to make the "Engage Parking Brake" light go off?

Max, A shot in the dark. Depchief just changed a hydraulic pressure switch down by the parking drum ....

I have no idea if that will help you ... any leaks in the system?

[TandW]

It is that high energy spark that is causing wires that are initially merely loose to "burn" at the plug. The IR gun has been used by yours truly. Good Luck!!

[DriVer]

Quote:

Originally Posted by TandW The IR gun has been used by yours truly. Good Luck!!

Chief, Can you explain where it is that you place the cross-hairs on the IR gun in order to get a reading that can be useful? Thanks.

[max49]

Quote:

Originally Posted by TandW It is that high energy spark that is causing wires that are initially merely loose to "burn" at the plug. The IR gun has been used by yours truly. Good Luck!!

My #5 409 boot was mushy and just pulled in half when I took it off. I tried to put the Taylor Supreme replacement on but the spring seems to be pushing it right back off the plug. I wonder if this could be why I always burn the #5 wire? I can't really understand the purpose of the spring in the beat shield. I'm thinking about taking the spring out and installing the heat shield without it.
This is probably the 4th, maybe 5th time the #5 wire has burnt out so I can't see how taking the spring out could hurt.

Quote:

Originally Posted by DriVer Max, A shot in the dark. Depchief just changed a hydraulic pressure switch down by the parking drum .... I have no idea if that will help you ... any leaks in the system?

I could try to get under there and look. I did add an oz.or 2 when this first happened. It should be worth checking. The strange part is that the powergear lights came on when we were driving down the highway. I had just got out of the hospital and thought it was just anorther powergear glitch when it thought the jacks were down. I did'nt realize it said 'engage parking brake' , that never comes on unless you turn the jacks on and no had done that.
Anyways,Thanks for the suggestion. So much of modern electronic digital stuff is just a PITA. I definitly can't see where it is better than the old 4 stick levelers, just more to go wrong.

[TandW]

Yes Max, leave the springs out as I have 40,000 miles ago. Take notice that as the plug wire boot is sliding onto the plug its ability to be wiggled back and forth diminishes and when the ferrule locks on to the plug tip this ability to wiggle is virtually gone. Target the suspect cylinder at the exhaust port, using an IR gun. The bad cylinder will be about 200 degrees cooler than adjacent cylinders. Good luck!!

[rgrstndgby]

As Tand W suggested, an IR gun aimed at the appropriate header will help ID a dead cylinder. If you have no gun, you can also start a cold engine, let it run for 15/20 seconds, turn the engine off, and feel each pipe where it exits the cylinder head. It will be apparant which one isn't firing...rgr...

[max49]

Another good idea, Thanks