blue thunder

Detonation

Mr Gadgets

blown formula,
If you suspect a plugged injector, I have checked them by pulling them out and apply 12v to the injector and spray carb cleaner thru them from the bottom up.. I put a white paper towel under it to see if anything comes out. There is a screen on the input to the injector. I have found all kinds of junk on the screen with this process.If you find anything a complete cleaning of the fuel system is needed.I would check them all just for good measure. You can get an injector connector from Napa and just hook it up to the spare car battery under the bench.
I have a filter before and after the pump to keep the injector screens clean.
Good luck.. I hope you find the cause.

Dick

blown formula

Turbojack....my piston has about the same black coloring but is not burned as deep. Mine only goes to the top ring land. I caught this early and was not nor had I been running hard. I also do not have as much "scatter" as you did (aluminum spray pattern on top). There was a lot of aluminum transfer to the cylinder wall though. On tear down, there was a little water in several cylinders, but since that engine was not running & there was several opportunities getting back to the dock & loading for water to wash up the exhaust (past the Salisbury flaps). At least thats what I ASSUME.
However, on removing the plugs (still in the water), I saw no evidence of water. I left the plugs out & then drove the boat about another mile to a ramp to load it. So, I think that is where the water came from.......but I could be wrong...??? I will try the injector cleaning trick to check for blockage this weekend while the block is being done.

GEOO

Did your engine run hot? What temp?

blown formula

The engine was never over 110 degrees...., oil pressure was always normal. Fuel pressure did drop to 35# from 45# (boost referenced regulator), but I was never in a boost condition. Fuel pressure dropped & stayed at 35# even at idle. I don't think that was the cause -because only one cylinder was affected.????

blue thunder

Really sounds like blown head gasket causing detonation.

BT

blown formula

Dang it !! I sure wish there was a definte & easdy to determine cause of this. With less than 10 hours on a motor, this should not have happened!!

blue thunder

If you weren't already measuring exhaust gas temp, maybe it would be worthwhile after rebuild in case the problem starts happening again. Couldn't hurt. I would have saved an engine I blew on memorial day if I'd known I had heat trouble going on in the combustion chamber. I still haven't tore that motor down cause I've been concentrating on its replacement. Pretty sure I was having a water leak from the exhaust into the combustion chamber on #1. Not sure though.

Good Luck,

BT

Nordicflame

Hey Blown Formula,
please clarify what you mean about the fuel pressure dropping to 35 from 45. Was this upon installation of the new FMU (regulator). In most ProCharged, stock MPI applications, the regulator must be adjusted to a static 50 and then increase either 2:1 or 3:1 relative to boost to increase to 60 and 65 lbs respectively with 5 lbs of boost. If I understand your situation correctly, 35 lbs sounds like a killer weather your under boost or not. ASM probably programmed the ECU to run your rated injectors at the higher pressure. Anything less and it starving.
I'm not that familiar with your setup so I may be way off base but I thought I'd throw that out anyway.
Later,
Dave

sgrady

The head gasket should tell a story if it was not damaged in the breakdown of the motor. Ususally though 2 and 7 are the problem cylinders. PM me, I can give you a couple of things to look for. What kind of blower were you using ?