UPDT: "Finished up the hg replacement. Also changed the timing belt (old one still looked ok though). Started it up and was smooth, a little high in the rpm's but nothing crazy. Filled the coolant and started to warm up to bleed the system, made kind of a single choke then ok. Then rev'd eradically and shut off. No CEL. Restarted ok, a few seconds later, repeated the process and shut down, despite giving it some throttle. The engine rev'd but i don't believe to the extent that the tach was indicating. Then of course shut down.

It seems like an electrical issue. Maybe once the engine heats up and goes into open/closed loop (whichever uses sensors to adjust the engine). Checked the electrical connectors but didn't see anything out of the ordinary. Called it a night. Any suggestions?

I think the first thing I'll do is disconnect the battery and clear any memory. Other than that, it doesn't seem like a mechanical problem."




Never changed a head gasket before so hang in there.

Turbo z6 for about 30k miles. The #2 cylinder started missing a few weeks back on start up only. The period that it would sputter varied, sometimes 15 seconds, sometimes a minute but would stop and run pretty normal. No smoke but I could smell coolant, although it's leaked from lines to and from the turbo in the past. Some liquid would seep out above the adapter plate on startup.

So I got the parts and ripped the head off. Pics are attached. The piston is a little cleaner but there appears to be a lot of carbon buildup on that cylinder's valves. I guess it must have been a small leak because there wasn't a visible problem and huge buildups of pressure in the reservoir. I'm not sure if oil was also a problem or was the problem. Maybe from the valve stem seals.

Anyway, it's not convenient for me to rip this thing apart and my alternate transport (girlfriend's car) happened to get fucked up saturday, the same day i put mine under the knife...figures.

 

was the oil milky.or did you notice any white smoke from the exhaust.

 

no milky coolant and no smoke.

 

I have been having the same misfire at startup problem, I replaced my HG 1,000 miles ago and I never re-torqued the headstuds.

Faulty injector or somthing? extra fuel would wash that piston like that and cause excessive carbon buildup on the valves, hmmm.

 

Pressure in the coolant resevoir as well as the clean looking piston make it seem to me as though the HG is blown for that cylinder.

I would take the head to a shop to make sure it is straight enough, install some head studs, and torque down a new gasket to be safe. Make sure the sealing surfaces are clean by first using a razor blade and some light steel wool if needed, and then w/some paint thinner or degreaser for safe measure.

Make sure you lube the studs w/a little oil when tightening, and go by the proper tq steps and specs.

GL

 

Did you switch your map and tps plugs when you put it back together? Do a leak down test? Other than that I dont know what to tell you.