^^^ Yuuup Even the slightest under the surface pinhole in the extender cap can cause this we have used an insulator wax with success in high salt spray conditions to limit this Industrial Wax Quality on the Line » Collinite
Here's what I found online regarding this via a quick search: This leads me back to my idea of building a spacer so that the wires can be routed away from the valve cover instead of crammed up against it.
I measured the ground connections and came up with the following: Block to Frame = 0.5 Ohms Block to Alternator Housing = 0.4 Ohms
I finished installing the new coils, and there is some improvement. Now the left side seems to only spark at the damaged boot and at the point where all 4 wires pass through the grommet. On the right side, it is still sparking at the neck of all 4 boots and at the grommet. I think I am going to pull the wires on the right side and clean and check all of them, then try again. I will also order another boot to replace the damaged boot on the left side. After the engine warmed up, it sounded like it might have been randomly missing on a cylinder. I am hoping that this is due to the damaged boot. More later...
I cleaned all or the wires and ran the car for about an hour today and now it is back to missing out at least one cylinder and possibly more consistently. I checked for flashes in the dark and all 8 plug boots are sparking along with random locations along all 8 wires. I tried re-rerouting the wires away from the valve covers and they stopped sparking, but the plug boots continued to spark. I found that if I move any wire within a couple millimeters of the valve cover, it would immediately start sparking at the closest point.
Instead of making spacers, why not try a heavy layer of gasket material affixed to bottom side of cover pate instead? Just an idea, and see if it helps.
I pulled the wires, cleaned and rebuilt them again today. Still missing out randomly when hot. Next, I am going to pull the spark plugs and check the gaps. What should the gap be for a 5.2 setup? - Tom
Plug Specifications Thread Size: 10mm Hex Size: 5/8" (16mm) Reach: 19mm (3/4") Seat Type: Gasket Gap: .028" (0.7mm) Heat Range: 7 Terminal Type: Solid Resistor: Yes Thread Pitch: 1.0mm Brand: NGK
I just went through this. The results of my research lead me to PMR7A for a 5.2. This was also Daniel's (recommendation). I also saw a recent Bradan thread which showed PMR7A.
It seems really strange that brand new leads are having this issue, it would seem to be a visible symptom rather than the cause. It sounds like there is excessive resistance at the spark plug, it should be the path of least resistance with a metallic connection to the head and earthed through the chassis if the lead to plug connection is good. This versus the discharging through insulation of the leads should be the path of least resistance. I would check any ground straps from the engine to chassis for corrosion and clean metal to metal contact. I would add an extra temporary ground wire if this checked out ok, ie no obvious issues just to eliminate grounding to the chassis. I would try brand new spark plugs with the correct heat range etc just because they are easy to eliminate, I wouldn't use any anti seize compounds on the threads of the plugs in case it increases the resistance. Good luck with it.
JL350, agree with your comments. I suggested in an earlier thread to verify the spark plug threads are clean and the block connections to ground are solid. Connections can show a good resistance when checked with a VOM but break down when high voltage is applied. Typically a megger is used to test high voltage circuits however I would not do this unless all other electrical systems are disconnected for fear of damaging components ( read sensors, ECU's, etc.). I would probably remove each spark plug cable and test out of the car to see if the insulation is in fact faulty. Also running a known good ground cable to the chassis is a good idea as you suggest.
