Talk me into, or out of, it...

[someotherguy]

So IMHO you are on the right track with the new plugs. Take a before photo or two now, so that we have
something to compare against 3-6 months down the road. (Note: In the case of cylinder #4, we might
get a clue after only a couple of weeks have passed. It's way different than the others.)

Yeah, I wasn't real happy to see the ugliness on that #4 plug, but at the same time it wasn't unexpected considering the overall state of neglect the truck had been suffering. That's about what the #1 plug looked like but it was obviously caused by a broken plug wire, as in physically broken in two. I suspect other plug wires were bad as well but when I removed them, most of them came apart, making testing them pointless. I replaced the wires and pulled #1 plug and cleaned it before re-install. Truck ran "OK" not "great" after that. (EDIT: this is over a year ago, when I bought the truck and was amazed it made the 200 mile trip home; clearly running stupid rich and misfiring)

I used to have similar ongoing maintenance issues with quality wires that I had spent good money on,
and I hated it when this happened. But once I started using dielectric grease on the inside walls of the spark
plug boots (applied with a Q-tip) the wires would then come off afterwards perfectly with nominal effort, and
thereby outlast the rest of the vehicle. No matter how many times I was in there looking for peppered plugs
or other clues as to the state of tune.

Dielectric grease is one of the greatest inventions by mankind, right up there with grilled food that's eaten
right away while standing up & engaged in tall tales with fellow old truck enthusiasts. :0)

I usually just put a small dab wiped into the tip of the boot, but with these big block heat shields, it's harder to grasp the boot to remove them - so I figured a bit more grease would be a good thing. I wiped some around the insulator of each plug, instead, to get a more thorough spread of it.

Richard

 

[someotherguy]

So back to the condition.. the truck is running well again. I figured the platinums already got mushed, so either they're toast, or not - so I used some square-jawed pliers I've got that are smooth, no serrations, and carefully pulled the ground straps away from the electrode, then gently mushed them against my worktop for some trial-n-error gapping, checked with the disc style gap gauge. Got them all very close to .040 and installed, hooked everything back up, and back to a normal idle and easy, smooth revs.

Whew. I'll have to chalk this stupid episode up to what's amounted to some really crazy last few days. Lots going on over here, not all of it great, but trying to get work done on the truck was a useful diversion.

Richard

 

[Scooterwrench]

Considering it but I'm curious on why you are so against them in particular?

They won't last any longer than regular 'ol copper core plugs,they just cost more.

BTW locally a CR43TS is $5/ea while they're $1.67 at Rock.

1, And most important is you're keeping local businesses alive. Buying domestic starts at home.
2, That's $1.67 before shipping.
3, If there is an issue you have to ship them back and wait for the replacement(s) to arrive.

 

[Scooterwrench]

This was exactly my default mindset the first time I replaced the plugs in a newly
acquired DD. I was at a brick-and-mortar parts store, fully intending on a set of my
preferred no-nonsense copper V-groove NGKs. And then a set of Iridium plugs also
showed up on the screen on special for nearly the same money? Wow, get jewelry-grade
Iridium plugs for the price of copper? What a deal!

I carefully installed these in 2020, thinking that at my advanced age these should literally last
a lifetime. :0) But not that long ago, I started noticing increasing drivability issues, and pulling
the plugs after 40K miles showed them to be completely toast -- the gaps grew from .045"
installed to ~.088" in the interval? The good news is that I took before photos in 2020, and
after photos in 2024, so no guesswork involved. And after finding the fine print in a remote corner
of the manufacturer's website it all now makes perfect sense: (Why didn't these last as long as I thought they would?)

****

@someotherguy, good on you for taking such an interest in reading your plugs as part of your
troubleshooting/repair effort. SES lights & DTC codes are a good starting place (if they kick) ...but
in reality it is just the ECM/PCM/VCM's considered opinion after running test routines that were written
in order to meeting an engineering deadline & EPA mandate a quarter-century ago. :0)

Live data is one step closer to the truth, but since everything affects everything else (bad ignition can
feel like a fuel delivery issue, and vice versa, even before you layer on a feedback loop) ...even a savvy
mechanic can still be led down the garden path.

But the closer you can get to the combustion chamber, the more unvarnished truth will be revealed.
And the most truth you can put in your hand is the spark plug that lives in that combustion chamber.

A lot of people like to make it seem that there is a lot of mystery to reading plugs. And if my buddy buys
a 250K mile work truck with plugs that have been in there forever, and he wants me to make a definitive
read? Well, this is one of those times where reading plugs is *still* a bit of a mystery. After they were
bought, did the mechanic installing them drop 1 or more? How are these exotic plugs supposed to wear?
And how did the PO drive the thing?

But if we replace those 'steeped in mystery' old plugs with a fresh set from a vendor we trust (from previous
firsthand experience) ...*now* we can have a set of plugs that will tell us valuable info. We will know how
many miles are on them, how the vehicle was driven, and even how many quarts of oil were consumed
by the engine since they were installed.

Pulling *those* plugs after a few thousand miles can give us a wealth of information. I personally gain
confidence in my understanding of what's really going on inside when I can compare what the plugs look
like (and the story that they tell) match the fuel trims that the live data stream is reporting.

So IMHO you are on the right track with the new plugs. Take a before photo or two now, so that we have
something to compare against 3-6 months down the road. (Note: In the case of cylinder #4, we might
get a clue after only a couple of weeks have passed. It's way different than the others.)

****

Anyway, the point I was originally trying to make is that fancy spark plugs sometimes have fancy fine print
that defy commonly held expectations. Buyer beware. :0)

I wonder if those fine wire electrodes act like glowplugs at higher RPM's?

 

[Scooterwrench]

A lot of good points and in line with what I learned working with my buddy Dennis as a mentor, decades ago. If he saw the counter person slap the box of plugs down (and for some reason they always seem to do it) he'd loose his mind and insist they get thrown in the trash, because that's what they were after that.

BTW, the old CR43TS's that came out didn't really seem to grow in gap.. in fact most were around .035; of course I don't know what they were when they were installed by PO.

So I started today by pulling the wires and checking resistance of each one to see if they were in spec. The generic 12K ohm per foot in mind, all of them checked out - depending on length, anywhere from 9K to just under 14K.

Then I pulled the plugs and it became rapidly clear why it was running so poorly. Some were smashed almost completely closed, less than .020. Only one of them was near normal at .040. Went ahead and ran compression test and got nearly even results on all cylinders, which was reassuring - about 165psi each, though it bled off quickly on every single one - not sure but I think the antique Snap-on gauge set I'm using has a bad seal somewhere.

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Kinda puzzled on these plugs as I don't feel like I went animal tightening them up. Also, I swear they didn't look like this going in; I'd like to say I would have noticed!! But it was a long morning after a long night, is it possible I overlooked these ridiculous gaps? The boxes looked brand new, no evidence at all of mishandling; I even just went and dug them out of the recycling to confirm. Comparing the ACDelco 1 to the CR43TS, they eyeball same length from seat to tip..

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Which brings me to the next issue.. now that I've found my gap gauge, I'm pretty sure you're not supposed to use these disc/coin style tools to gap a platinum plug.. right?

Richard

Another piece of experience tip. Those smooth sided insulators will allow spark to travel down the sides and short out to the valance. I discovered this the first time with those E3 plugs. Installed a set into a customers car and the first time they hit a rain storm they got a miss. They brought the car in and of course it ran fine, on a dry sunny day. I misted the secondary ignition with a spray bottle and it immediately started missing and I could hear the fire popping and when I looked down at the plugs the fire was shooting out from under the boots and running down the insulator to the valance. There is a reason why Albert Champion designed plugs with ridges in the insulator over 100yrs ago. Those ridges effectively lengthen the distance from the tip of the plug to the valance. It works so well that Model A Fords ran open brass straps from the dist. cap to the plugs without missfires.

 

[Road Trip]

I wonder if those fine wire electrodes act like glowplugs at higher RPM's?

Yeah, it's hard to say. All I know at this point is that I learned enough to know to avoid
going there in the future, and just write all this off as the price of ongoing motorhead tuition. :0)

Given that the plugs on the K24a couldn't be any easier to reach, and also have
a robust COP (Coil On Plug) setup driving them, the classic V-groove NGK plugs are more
than good enough to satisfy even the fussiest owner -- me. :0)

And after another 40K more miles no doubt these old school V-groove copper plugs will
have eroded from .044" to maybe .050". Much better than the .044" to .088" that the
'affordable Iridium fine wire' plugs delivered. What can I say? I just managed to prove
the KISS concept to myself. Again.

 

[Keeper]

I haven't pulled my NGK ruthenium plugs since I put them in around 30k'ish ago, but the truck immediately ran better with them and have had no issues since. They came gapped at .045.

for whatever that's worth

 

[Scooterwrench]

ruthenium

Who is she?

 

[Keeper]

Anyone want 5 of these bad boys for free. Bosch 4458. They fit our engines apparently. $29 a piece on Amazon. They were just extras in a box I got.

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[fancyTBI]

Dang it. I should have low-balled you on it while it wasn’t running right.