i've searched around... talking about spark plugs foul.... but how does it define foul ?

the ceramic turned black considered foul ? or something ?

i had my plugs out... i've been using this for quite some time...
these are heat range 10.5 iridium plugs... they are HKS/Denso plugs.

i've been using this for more than 1 year... yes it serve be quite well.. power, etc everything okay until i realise the iridium tip is getting lower and lower... so i took it out permanently. replaced it back with BUR9EQ for all 4 pcs...

need some guidance if these plugs are foul.....




also.... the moment i put those new plugs in... i realise there are knock on WOT... just wierd... but later.. the day... it disappeared... what can cause this phenomena ?

 

 

Need actual pictures of the tip of the electrode. From what I can faintly see (white tip). They look lean if anything. They should be a nice brown color if everything is cherry. Clean them lightly on a wire wheel and re-install...

 

from what i extensively double searched... my plug seems to be worn.... from sharp and errected tip... to left around 0.2mm tip...

the insulator doesn't seem to be foul badly... but it's close to getting fouled...
it's been in my car for last 1.5 years...

 

i think hes running a little rich. but not much

Rich = black carbon buildup on plugs
Just right = light brown looking
Lean = Very light brown/white

correct me if im wrong.

 

You're right Jim. Although you need to look at the center of the spark plug. That's where the electrode is for the spark plug. If you look there you'll see the white spot.

 

hey i just saw your post...

check out this thread i posted in, it might help you. i dont feel like re-typing all that crap(scroll down near to the end):

https://www.rx7club.com/showthread.p...=1#post7655329

i think you plugs are fouling cause there to cold. if the tip is to cold, deposits will form on them and they will short out the current. i really think this is your problem.

 

what does a foul mean anyway?

 

You can't accurately tell if combustion is lean or rich from just looking at the plugs unless it is REALLY bad. You have to do a "chop" so you can see the base of the insulator. Everything else is speculation.

 

i have a closer shot of the plug and its tip..

 

wire brush and some alcohol wouldn't hurt...

 

my car fouls plugs every time i drive it!almost! i need a tune badly!

i have about 8 sets i interchange, i just bead blast and reuse.
and IMO it is alot better than wire brush.