masterdill

iTrader: (2)

Is a NGK TR55 gapped at the factory gap supposed to look like this after 10 miles and a few WOT runs?



I've been having a miss but we tracked it down to an exhaust leak since it dosen't stumble with the cut out open.

Autotap reads 11.7:1 A/F at WOT, real lean (this is a stock fuel / spark curve 2002) at crusing speeds. I mean like 14.7:1 or so. Would this cause the spark plug to look like this? Is this plug still ok? I need some expert opinions here... is this a normal plug?!

mcflyz28

yes, rich would be black

Colonel

A few points...

1. Autotap DOES NOT read WOT fuel/air ratio. It has the parameter but it's incorrect. Why? Because the factory O2 sensors are narrowband, not wideband, and thus, they don't have the capability to return accurate readings outside of the stoic range.

2. 11.7:1 (if it were accurate, which it's not) would be very rich, not lean, for WOT operation.

3. 14.7:1 is stoic and is what the PCM shoots for during closed loop operation. There's nothing wrong with that.

It's hard to tell much about that plug from your fuzzy picture.

masterdill

iTrader: (2)

So the extreme white condition on the shank or whatever you guys call it is ok?

Colonel

If by "shank" you mean the "side electrode" or "ground strap", then no, that's not ideal. It's hard to get a good reading with modern day unleaded gas but I'd say you might be running a bit lean at WOT. What are your B1S1 and B2S1 O2 readings at WOT?

masterdill

iTrader: (2)

.920mv

Will the white color affect the power level my spark plug puts out? I just went through 3 sets of spark plugs (TR5, TR6, and now TR55). All of them are white, and now that I tracked my problem down to a exhaust leak, I'm beginning to think that the white condition is normal. I don't know. I'm going to go do a few 0-60's on the g-tech and see if the performance is improved any with the cutout open...

Colonel

I seriously doubt you're running lean with O2s in the .900 range.

All the plug has to do is spark. If it's doing that then the power is going to pretty much be the same regardless.

Plug color has alot to do with what kind of gas or additives you're running too.

sawedoff

iTrader: (3)

From what I can see from the resolution, the plug looks extremely good. As long as it's not wet or "sooty", you're okay. If you had detonation you'd see small specks of metal, that'd look like somebody spary the plug with metallic spray paint. If the ceramic (white part) is bubbled, you would be overheating the plug, and need to adjust to a cooler running plug. That white condition is optimal. So, you're doing great.

Joe Overton

Plug looks good and porcelan being like out of box is normal ..if you notice face of threads and lower on the ground strap is dark which means at some point whther its wot ,cruise or idel its lil on the fat side...without being able to inspect the fire ring down inside the plug hard to tell ..but first glance even with pic fuzzy plug looks close to optimal... as mentioned above it can be like new looking longs no peppering is evident...