dbman96

OK Guys I need a hand figuring out how to read my plugs - just did a valve adjustment and thought I'd take a look at these beautites. I've seen some cheesy b&w pics and ideas of how to read plugs have very little experience and a picture is worth a thousand words... so I'd love to hear what you guys can tell me:

Sorry I can't get but one pic to work but all 4 are at the following link:

Spark Plugs

Plug 4:




[Modified by dbman96, 1:12 AM 2/27/2002]

MiraiZ

3 and 4 a tad rich...but okay

SEFIxCivic

your ground straps look like it has some salt and pepper on it. that's not a good sign. what plugs are those btw? the should be tan looking with no deposit on the porcelain or the ground strap. some black carbon is acceptable on a street car.

dbman96

I think I may have some mixed signals - I'm pretty sure I was running lean under boost when I had my FMU in place, for quite some time - now I'm definitely running rich with the FMU removed. I think I need a fresh set of plugs to see how they're doing under my CURRENT setup.

The plugs are... um... the ones that were widely recommended by that Endyn guy... don't remember the number now. Bosch but I don't remember which ones. Duh.

SEFIxCivic

i like the BCPR7ES-11. trying some new plugs and examining those sounds like a good idea.

dbman96

I believe that's the plug I'm running. I was mostly concerned about the scarring on the ground strap you referred to and the white buildup on the electrode.

DSF

They look like Bosch platinums to me.

VTC_CiViC

Well here's my humble interpretation:

The insulator around the electrode seemed very bright white in #1 and #2, BUT, that may be the flash distorting the true color because #4 looked ashy grey. Also, #1 looked like it was developing small "bubbles" on the electrode, blistering. But again #4 shows that might just be ash deposits that look white because of the flash. The ground strap looks ok, but it does brighten at the tip some. Perhaps a little too lean? Very ashy plug too, mine are darker and fouled more than yours, but are without any kind of deposits.

turbosol

I've always heard that if your plugs have what looks like very small metallic looking deposits that it is from detonation. Just my experience

betsuni

is it possible that your plugs are the wrong temp for your application? to me it looks like it's not reaching the temp where it self cleans the tip....just maybe, im no expert.

SEFIxCivic

the bcpr7es-11 is an ngk plug. do you have any method to richen up your mixture perhaps?

TurboMiata

What is your setup? I noticed you said boost......

Cylinder 1: White, That is knock. Might want to do something about this pretty soon. Either reduce ignition timing, insert more fuel, or reduce boost.

Cylinder 2: AHH!! WAAAAY too white. See comments at the end of Cyl 1.

Cylinder 3: knock......Also running rich. DO NOT lean it outhowever. the richness is probably the only thing saving your engine......

Cylinder 4: richer than the others. Knock once again.

Got a fuel rail? What size injectors are you running? The fluid dynamics in the stock fuel rail arent appropriete to flow as much fuel as you are through there. Looks to me that you have uneven fuel distribution. Reduce the ignition timing or lower the boost. Either way, cylinder pressures MUST come down. Unless of course you *want* a reason to rebuild the bottom end due to holes in the pistons.....

I would also see about fixing that fuel distribution problem. Either that, or tune to the WORST cylinder. (IE: the one with the most knock)

Knock = bad. When a piston is trying to come up, and a burn event happens thus attempting to push the cylinder back down while in the middle of either a compression stroke, or exhuast stroke, its bad news. Rod bearings, rods, pistons...they dont like that kind of stuff

SIK IN DA HED

mine are kinda light white on the top like that but not so much. also found some traces of oil on the screw part of the plug. i wonder that means. anyone got a link on how to read plugs?

TurboMiata

Screw part of the plug? Checked your cam cover gasket lately?