Reading a sparkplug

[Puller]

I have a nearly stock 1g...KnN, mbc with stock boost, maybe some boost leaks...idles fine but hesitates...stock wires, the plugs arent fouled but they are blackened a bit below the electrode...also there is yellow creeping up the insulator...what does that mean? my car is a dog and won't accelerate properly even under boost...its hardly drivable and when you rev from idle, it kind of delays and makes very mild popping noise and then climbs....any help is appreciated.

 

[v2ner]

i know that when spark plugs r white, it means ur runnin lean. when they're very dark, ur runnin rich. maybe u should check to c if their is any moisture in the spark plug chambers. as for the yellow thing, i'm not quite sure. i remember my car ran like shit but then i switched plugs and made sure they were gapped correctly and it was great. i don't know if any of this helps.

 

[Puller]

yeah i knew that much..thanks anyways

 

[luv2rallye]

The yellow can be due to spark jumping across the insulator because the spark plug wires and/or plugs are old, cracked and worn out, or wet.

 

[Puller]

alright, how would they get wet...the oil is fine no coolant...very clean...can you describe what might happen...also is that enough to make the car run like crap...? i'd say so i just don't want to get my hopes up when it might be compression or something.

 

[luv2rallye]

Crap? You bet! Old spark plug wires deteriorate over time and lose their insulation properties and so could let the spark jump through them to the nearest ground. Sometimes you can see it under the hood if you have the car running in complete darkness. Old wires also tend to get hard and bittle which is a sign of this. Test how easy yours flex.

Not that this is the only possibility for your problem but if it is, it would run like crap at any speed.

 

[Puller]

oh ok that produces some relief...im doing a compression test today, hopefully that won't reveal any news other than good compression or im fudged. also what could the black around the threads indicate? obviously its rich but the electrodes arent black themselves...much appreciated.

 

[luv2rallye]

If the plugs R black on the outside of the threads, they might just not be tight enough. Anyway it sounds like you should invest in new plugs no matter what you find. I'm glad you're doing a compression test. Remember the plug wire boots on the wires also get old and damaged over time.

 

[Puller]

yeah compression is over 160 across the board! woohoo! thank the lord...im thinking the timing is off, new plugs didn't help..ill check it tomorrow..the idle is a little lumpy and i think the guy before me has the balance shaft flipped.