Atomic

iTrader: (42)

Pretty much exactly right. I use hptuners and have become pretty proficient with it, but reading plugs is something I don't have a lot of experience with. I know a grainy insulate means too much timing and sooth black is too rich, but not much beyond that. I appreciate everyone's insight.

fastnblu

iTrader: (2)

I wondered why I've seen lighted magnifiers for reading plugs. Heck, I just saw 1 a couple of days ago. I thought it was for workin in dark / poor light / or those w/. bad eyesight. Now I know... it's to look down inside. I never knew more than a few things plugs told, not everything. In fact, I came across some info very recently.

WOW! You're old!!!

The part about leaving carbon behind & (-) fuel trims is interesting.
You reminded me I left my old Iridium plugs at my tuner's.

He threw them out by now I'd think. It's been ~2 wks. since my tune.
I wanted to read my plugs in detail. Only one looked a teeny, tiny bit oily on threads. Any guesses? It was #7. I keep hearing of horror stories on #7, if there's 1 cyl. that'll be an issue on LS motors, it's that one. Anyway, what makes reading an Iridium plug different, other than their longer service life?

mhotrodscooter

iTrader: (13)

I thought when reading plugs, you must go WOT & then throw it neutral & kill the motor.. To get the reading. Is this still true?

budhayes3

iTrader: (19)

LOL, I was speaking facetiously

I've always thought so too...and I'm referring to factory applications btw, with factory replacement parts, so incorrect heat ranges are not the case. I used to see blackened plugs all day long on 88-91 4 cyl Camry's that were getting poor fuel economy and down on power with an occasional stalling condition. (Before OBDII and scanning software with fuel trim capability...used to use a lab scope to aid in diagnosis until I got used to the symptoms and "knew" the problem 90% of the time) The source of the problem was a bad coil (1 coil for four cylinders). At times the car would run perfectly, but as it heated up and resistance rose in the coil, it would get a weak spark and incomplete combution, and intermittently lose spark and stall. Then start right up and run good to decent again.

That may be a procedure used in performance applications (I'm not familiar with it), but as a factory line technician (let me pound my chest a little and mention Toyota Master Diagnostic Technician btw ), I've always just removed and inspected them. For the most part, as mentioned, you inspect plugs as a diagnostic tool when something is amiss.

MikeGyver

iTrader: (5)

Yeah, but it's not necessary to put it in neutral. Also, new plugs help.

mhotrodscooter

iTrader: (13)

Are we still looking for white with black spots or just tan in color?

MikeGyver

iTrader: (5)

After a few seconds at WOT, with a new-ish plug that hasn't idled much, the nose of the insulator should be clean white. Not burnt white, just kind of new looking. At WOT, tan would be too cold of a plug.

LS1TRUCKGUY

iTrader: (7)

here you go. they are talking about tuning for n20, but you get the idea. https://ls1tech.com/forums/nitrous-o...g-reading.html

JS01

iTrader: (10)

If you are trying to tune WOT off the plugs this is the only way to go especially if you're trying to read the ground strap for timing.

budhayes3

iTrader: (19)

That's pretty interesting about the WOT pull plug reading, I've never heard of doing that...cool trick