ONE spark plug burning out - VT

[phatvtcom]

In relation to my other thread about missfiring
Vt - lossing coolant strange problem???
The problem wasn't anything but a very severly burnt spark plug that was causing the violent backfiring. ONLY ONE PLUG! I changed them about 3000km ago because the same backfiring problem was happening then. Now seems to be burning quite frequently between 3000-5000km and only that one plug. I suspect it may have something to do with oil leaking on it becuase i pulled it out and it was fairly oily. It's only really badly buring on the white park of the plug. The tip where it sparks seems to be fine. What could be causing this?

[VTS5]

Change/replace its coil pack.Also check your leads,make sure they'r not cross plugged.

[phatvtcom]

Thanks I'll check them out! As for the oil? Does that have anything to do with it? I'll post a pic of the spark plug tomorrow

[Shen Long]

sticky valve maybe?

[phatvtcom]

This plug was the one i removed about 3 months ago due to backfiring. Got pretty annoyed when my mechanic told me he'd checked everything and my spark plugs had a good 5000km left on them, i got the car back home and it was still having the same problems so i just checked and changed the plugs myself after paying $300 for nothing!




And this one i removed just the other day. Doesn't look as bad as the first one but still caused some pretty nasty backfiring. So really this plug has only had a life span of about 3000-4000km. The gas mixture has been checked so it's not running too rich.

[Claudy]

Oil on the outside the plug is more than likely just from a rocker cover gasket leak

[phatvtcom]

I've changed the rocker cover gasket just the other day so that shouldn't be an issue, but i think you're right it's definitely coming from somewhere else.

[pablo]

Just as a side note, I see that you don't use any anti-seize lube on the threads. Fitting plugs dry isn't a good idea, particularly in the long run.

[phatvtcom]

Havent had any issues taking them out so far, but i'll definitely keep that in mind for next time, thanks!

[Brett_jjj]

Ive seen plugs before that look like the ones in the pics, the ones I saw were caused from the sparkplug not being tightened up to the recommended torque specs. This caused them to slightly leak hot gasses etc past the plug, which then burned the plug leads onto the plugs slightly, leaving the burned or scorched marks on the plugs.

[phatvtcom]

Oh really!? Would have never thought of that. What's the best way to know they're in properly?

[VTS5]

Is it a dual fuel car?Cause its very strange to see backfiring petrol engine!Unless,there are some cross fitted leads/faulty plug/s or faulty coil pack/s.

[wana s' charge stock vt]

send an email to bosch or ngk with the pic, they're pretty helpful and should know what causes it...

[phatvtcom]

Yeah mate she's on LPG. Good idea I might just do that, thanks!