Looks like my cylinder 4 is taking a dump on me. Got brand new spark plugs, and it ran ok for about 10 seconds, then immediately went back to misfiring.

I'm looking towards a faulty injector being the cause, but what other diagnostics should I be running?

 

Just saw a issue where a tune was not fueling fuel trims and was causing a missfire. But yeah start with your basic and rule things out.

 

I've been on this tune for a while now, so I can rule that out.

Pulled the rail and I found:


That 0-ring is in perfect condition, but that's a lot of buildup around it.......

Anyways, is it possible Coil packs could be an issue here? There is no smoke coming out of the tailpipe (from what I can tell).

 

Swap the coil pack from #4 to another one, if the misfires follow it you found your problem.

 

Waiting 10-25 miles before checking that code again, to see if the misfire went from 4 to 2.

Anyone know if a Leaking/blown head gasket could be the cause? I could have sworn I smelled coolant on rare occasion. I'm paying close attention to the coolant levels to see if it goes down, but I haven't driven it enough to check.

 

do a compression check

 

That was my next step. Cyl #4 picked an absolutely horrible time to go out

 

these engines arent hard to rebuild and the **** around the injector is typical

 

I meant that it went out right around the holidays. Busy, low on funds, and everywhere is closed on Christmas Eve/Christmas.

 

i feel you on that dude

 

Compression Test Results
Cylinder 4: 55 PSI


****


The good thing is that i'm not losing any oil, so that rules out Rings (pretty much, anyways). Unfortunately, i'm not losing coolant either (pretty much removing a head gasket possibility). So the likely cause is a faulty Exhaust Valve.

Either way, it's not going to be cheap

 

yes the rings are gone and probably a piston ring land that is why the cylnder pressure is so low

 

My friend was talking about how he blew the lands out of his pistons, and it had similar symptoms. Is it possible that I wouldn't lose oil, even with blown rings?

 

yup i had 3 comp rings broken and a ringland and dident lose oil

 

But, what if I want it to not be rings?

Please?

If it is a piston ringland/ring, that means heads pulled, re-sleeved, new rings, and likely new piston/rod.
If it's an exhaust valve, it's much, much cheaper. Still have to pull the heads, but i've been meaning to anyways.

ARP head studs, cometic head gasket, possibly a new 4th cylinder replacement(or Exhaust Valve).

Yay! ****!

 

i doubt the bore is hurt you wouldent need a new rod just a piston and a rod bearing and rings foe that cylnder and its not a bad valve

 

Turned out to be a chipped exhaust valve, possibly a cracked head.

Just replacing the head gasket/ARP studs and labor was 1300, so it'd be close to $2,000.00 if the Heads are cracked.

Magnaflux will reveal all on Monday.

 

Cracked head replaced, New valve/guide/spring, cometic head gasket, ARP head studs, and labor cost me right around $2,000.00