Engine Tapping

[Mark-v]

Hi guys hoping one of you lot might have an idea...

My 182 has currently got a misfire when on closed loop and has been diagnosed to be the upstream lambada. But it's also got a fairly loud tapping noise from the head area (kinda like spark knock) so i took the plugs out and noticed the pistons are excessively carbonised just wondering if it is A: likely to be the cause and B: best way to clean it off without taking the head off.

The car has 79k on it and oil change just done also tried changing HT leads and plugs. I've kinda run out of ideas now without taking the head off to see so getting rather fed up with it

Thanks in advance

 

[Russ_16v]

How did you see the pistons through the plug holes mate? Camera?

 

[Mark-v]

How did you see the pistons through the plug holes mate? Camera?

I just looked down there with the plugs out and it seemed a bit damp (presuming over fueling from lambada being knackered) bit the piston tops looked almost flocked lol

 

[Russ_16v]

Pistons generally do always look black, and looking down wont give you a good indication.

What do you mean by a bit damp?

Also is it a tapping or missfire mate?

Also did you use the correct plugs?

 

[Mark-v]

Pistons generally do always look black, and looking down wont give you a good indication.

What do you mean by a bit damp?

Also is it a tapping or missfire mate?

Also did you use the correct plugs?

The piston looked wet in the center and kinda oily although it's not burning any oil, it's tapping and misfiring but misfires only when it's on closed loop which is pointing me at the lambada, plugs are NGK PFR6E-10 (ones that Reno use)

Thanks for your time btw

 

[Russ_16v]

Hmmm, does the missfire/tapping clear with revs or stay constant?

im leaning towards lambda too, but kinda worried about the tapping, any chance of grabbing a vid mate?

 

[Mark-v]

Hmmm, does the missfire/tapping clear with revs or stay constant?

im leaning towards lambda too, but kinda worried about the tapping, any chance of grabbing a vid mate?

the noise certainly becomes less apparent at higher revs and seems to be related to the cam speed (eg every revolution) car still pulls well but feels very harsh like you would from very high compression (what also made me think carbon build up from misfire)

i can try grab a vid tomorrow so you can see what ya think

cheers