I have been having issues with plugs grounding out and bad wire, changed the wire and it still was acting up. So I pulled the plugs and replaced them with another set, now it seems fine again. Put the old set on the meter and one was 1.78 ohms, the other was over limit. I checked a new one in the package and it was 1.92 . What the heck is going on with plugs, BR8ES solid tops, and what percentage are junk?
Anyone ohm out their plugs?
- Thread starter Crab
- Start date
Trying to track down the misfire, it was on the trailer and only at high rpm, wouldn't rev out properly. I now have a way to confirm when a plug is dead, short of just assuming.
- Location
- Near Seattle WA
Misfire.
Knock the plug gap to .015" and see if the misfire goes away.
Knock the plug gap to .015" and see if the misfire goes away.
I have been gapping at .o25
Yes.
So what are you concerned about?
1.7 Ohms vs. 1.9 Ohms?
Or the one "over limit"?
What scale was it on when it was "over limit"?
From an electrical standpoint, anything in the Ohms, or even kOhms is inconsequential. The gap has a couple megaohms resistance, so a little extra in the plug is not noticable.
1.7 Ohms vs. 1.9 Ohms?
Or the one "over limit"?
What scale was it on when it was "over limit"?
From an electrical standpoint, anything in the Ohms, or even kOhms is inconsequential. The gap has a couple megaohms resistance, so a little extra in the plug is not noticable.
Yep, unless there is an internal flaw in the plug, the small difference in resistance won't make much difference. If the plug is faulty it might be shorting to ground internally before the air gap thus causing a misfire. I have never had a new faulty NGK plug that I can remember. Not to say that it is not possible. I would be more suspect of flakey plug wires or some other external cause for the misfire.
I suspect the internal shorting, it would fire until cylinder pressure and rpm caused it to fail. I fixed the wire issue with new wire. I think the scale was 200 ohms, its a Sperry multimeter.
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I have seen engines that were spitting small amounts of metal from a failing crank bearing or metal from deto causing plugs to foul on the cyl that was getting ready to fail from the more major cause. The plug would look like it was burning fine but it would appear fouled or shorted. I hope your problem is electrical and not mechanical. Good luck.
- Location
- Near Seattle WA
Gap
Originally Posted by Watcon
Knock the plug gap to .015" and see if the misfire goes away.
Did you try this yet?
Originally Posted by Watcon
Knock the plug gap to .015" and see if the misfire goes away.
Did you try this yet?
WFO Speedracer
A lifetime ban is like a lifetime warranty !
- Location
- Alabama
I have seen brand new NGK plugs that were bad but it is very rare.
63chevyll
#56
- Location
- in my garage, colorado
yeah try this,
I was chasing a miss i had only in salt water. had a mis in TX and FL salt water only, no mis in fresh water.
in the salt i had to gap my plugs to .010 to run. i can run .025 in fresh water. But a definate miss with .025 in salt water.
I have new coil and wires and everything was greased up.
SJ/XPBri
Just SJBri = no more XP
- Location
- Northern, NJ
Monday I'll take a a plug and megger it to see how many MΩ it takes to clear a given gap. This could get interesting, anyone know what the stock coil output is vs. lets say an MSD TL setup?
Bri
Bri
BruceSki
Formerly Motoman25
- Location
- Long Island
with stock ignition my ski doesnt like to run well unless the gap is super small.... it will miss a lot both in and out of the water.
i just keep the gap almost closed and it runs like a charm.
hopefully an msd enhancer down the line will give me a stronger spark and help this problem out... till then its tiny gaps on my plugs for me
i just keep the gap almost closed and it runs like a charm.
hopefully an msd enhancer down the line will give me a stronger spark and help this problem out... till then its tiny gaps on my plugs for me