Mis-fire Cylinder #2...now #2 and #3

doulos4jc · Jul 23, 2016

Two weeks ago car starts running rough, then Check Engine Light. Checked codes; P0300 engine mis fire and P0302 mis fire #2 cylinder. Replaced plugs, and checked for vacuum leaks, now I throw a P0302 and P0303(mis fire cylinder #3)!?!?! Gonna take it to dealer if I have to so I've taken all my mods off with the exception of active grill shutter delete. Any help?

Travis@boostworks · Jul 23, 2016

What did the plugs look like when you pulled them?

doulos4jc · Jul 23, 2016

Plugs looked surprisingly good. Down pipe had pretty good layer of black carbon build up.

Edkiefer · Jul 23, 2016

While you had plugs out, should of checked gap, many have had gaps all over the place.
Also for high boost seems sweet spot is around 0.028 gap, if my memory is good.

PS: there a thread about this.

perfweld · Jul 23, 2016

Are you using methonol / water injection ?

doulos4jc · Jul 23, 2016

Update/fix

Problem found/fixed...bad plug. I didn't replace plugs(I should have)I just pulled and inspected them, and reinstalled. After pulling them a second time I found insulator and electrode completely broken off of one plug. They were the Denso ITV22 for what it's worth.

mustang1 · Jul 23, 2016

doulos4jc said:
... I found insulator and electrode completely broken off of one plug. They were the Denso ITV22 for what it's worth.

does a broken plug mean there is pre-ignition / detonation ?

perfweld · Jul 23, 2016

mustang1 said:
does a broken plug mean there is pre-ignition / detonation ?

Could be a lot of things, but the very most likely cause would be detonation.

doulos4jc · Jul 23, 2016

Bad plug...very bad plug

doulos4jc · Jul 23, 2016

perfweld said:
Are you using methonol / water injection ?

No...mods were CAI, intercooler, down pipe, Wastegate acuator, one step colder spark plugs, and of course tune. I want to do meth in the near future, I'm not going to tune for it though.

perfweld · Jul 23, 2016

doulos4jc said:
Bad plug...very bad plug

You do understand the porcelain dosent just drop on its own free will.

Cobra Jet · Jul 24, 2016

doulos4jc said:
Problem found/fixed...bad plug. I didn't replace plugs(I should have)I just pulled and inspected them, and reinstalled. After pulling them a second time I found insulator and electrode completely broken off of one plug. They were the Denso ITV22 for what it's worth.

If the insulator and electrode have broken off as you have stated - those pieces are now where....

Heardcuh · Jul 24, 2016

I have problems with my denso's too, last set my cyl 3 insulator came down just like that. I ended up driving maybe 50 miles on the plug, idle would have the bump every few seconds and the car felt down on power. Pulled the plugs and found the offender. Now I've got a new set on, AFR goes up and down everyone once a while and sometimes my idle feels a little rough, especially on cold starts, the normal four cylinder hum has a few extra bumps but not like the pronounced misfires from when the plug broke. Gonna pull them tomorrow when the car is cold and check them all. My plugs are always black around the first few threads.

Miglo · Jul 24, 2016

Cobra Jet said:
If the insulator and electrode have broken off as you have stated - those pieces are now where....

Pretty much this^^^^^^

Once that porcelain drops into the cylinder, damage usually begins exponentially if your still driving it like that...

But hey, where's that Kermit the Frog meme at?

doulos4jc · Jul 24, 2016

Cobra Jet said:
If the insulator and electrode have broken off as you have stated - those pieces are now where....

cracked in two is more accurate than broken off, the insulator/electrode moves up and down about a 16th of an inch.

Mis-fire Cylinder #2...now #2 and #3

doulos4jc

......looking^

Travis@boostworks

Well-Known Member

doulos4jc

......looking^

Edkiefer

Well-Known Member

perfweld

Well-Known Member

doulos4jc

......looking^

mustang1

Well-Known Member

perfweld

Well-Known Member

doulos4jc

......looking^

doulos4jc

......looking^

perfweld

Well-Known Member

Cobra Jet

Well-Known Member

Heardcuh

Well-Known Member

Miglo

Well-Known Member

doulos4jc

......looking^

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