Pistons not firing 100%

[tayl51601]

On the weekend i replaced the spark plugs, they were fine for about 20k's of driving, i then decided to rev the car out to 8,000rpm and ever since then my car is running as though one of the pistons arent firing 100%

Some may know of the "wrx" noise a honda motor will make if a piston is dropped, mine is making a very slight "wrx" noise, i thought it was just me being paranoid at first but it definately has a slight noise of a faulty piston, also there is more smoke than usual coming out of the rocker cover and the pcv valve.

The replica mugen rocker cover i have on had loose paint around the spark plug holes, this paint is almost like rubber.
I personally think some of that paint has dropped into the hole when the plug was out which is getting in the way of the spark, which would explain it not firing 100% as well as the extra smoke coming out.

Im planning on removing the whole head this week to get to the top of the piston to find this paint. The thing that i would like to know is does anyone recommend anything before i pull the whole head off for absolutely no reason?? Is there a way of cleaning the pistons without stripping everything apart??

[lil_foy]

Is the sound coming from the engine itself or the muffler?

Did you check if the gap was all good on the plugs?

[tayl51601]

Its coming from both the engine and muffler, you can feel it when sitting in the car when idling.

I didnt check the gap no but i thought it might have been a faulty plug in the pack so i changed them back to the old ones, still the same problem so i just changed back to new ones so the gaps must be fine.

[aaronng]

You checked your dizzy and leads yet?

[tayl51601]

I checked the leads, im going to check the dizzy with a multi meter hopefully tonight.
It cant just be coincidence that the dizzy went 20km after i changed the spark plugs lol even though i hope it is the dizzy!

[Limbo]

check leads.

lower the gap to .9mm or even lower like .6mm
I had the same problems when i gapped mine to 1.1mm

If it is acting up on idle, could be you've fouled your plugs.
Buy some cheap copper plugs and try putting them in.

Then if that doesn't help, try the following;

1) check voltage & earthing
2) check map sensor
3) check ECU

i just did all these over the weekend also cos i had a similar problem

[tayl51601]

Its definatley not the plugs or leads, i changed them both back to the previous plugs and stock leads and the problem was still there.

Did you end up finding what was causing your problem?

[onnos]

it sounds like u smashed a ring land.aka cracked piston. if it breathing heavier ie more smoke coming out the breather then combustion gases getting past one of your pistons and into the sump. another sign it a cracked piston is the wrx noise. a simple compression test will determine if it down on compression and a leak down test will determine if it a shagged piston.as for the paint it would have to be a big chunk of paint to block the spark. small bits of paint would be burnt or pushed out past the exhaust valve.

[TODA AU]

Its definatley not the plugs or leads, i changed them both back to the previous plugs and stock leads and the problem was still there.

Are you going to finnish the job?
Did you check the dissy cap & rotor button like Aaron said?
Have you done a compression test yet ?

[tayl51601]

Are you going to finnish the job?
Did you check the dissy cap & rotor button like Aaron said?
Have you done a compression test yet ?

I was planning on stripping the head off tonight but was going to test the dizzy first.
It cant really be a sparking issue though could it? Not with the amount of smoke thats pouring out, its getting gradually worse everytime it starts so it might be a cracked piston........
Wouldnt mind forged internals but i do mind the long trip back to you! lol

[JasonGilholme]

i had a rough idle problem and it was the ICM in the dizzy.

But i wasn't blowing any smoke. I was getting hesitation in the RPM range as well cause it was missing firing everynow and then.

Check these things first before you go opening the engine.

[tayl51601]

Im going to try buy a compression tester tonight and test the pistons.

If my pistons rings are gone i know that it will cause it to smoke out of the head but will it cause that "wrx" noise?? Theres a fair bit of smoke pouring out at the moment, mainly out of the catch can which is only hooked up to the pcv valve. Thats why im almost certain its the pistons, probably oil leaking in there. whether its the rings or a cracked piston i dont know until i get inside there.

I guess it cant be that paint because it would have burnt away by now, like onnos said it would have had to be a big chunk of paint for it to last this long.