springer.83

Strange problem occurred this morning. My trooper of a '06 LS decided it did not want to start. Turned the key and the starter runs, but no joy on starting. Looked under the hood, starter causes the serpentine to run, so it is actually engaging the flywheel. Good, but still no joy. Fuel pump can be heard, and with the air filter assembly off, I can smell the gas after trying to start the car. Unfortunately, I do not have the appropriate tools on hand to pull the spark plugs to check for compression and spark. The engine, with starter running, sounds strange. Strange in a "too quiet/ too easy" way. My next route is to just verify that all of my fuses are good, but I'm predicting that to be a low probability root cause.

springer.83

Ran the compression check on one hole so far and got no compression. Going to run the rest in the morning. I've heard some slight ticking during startup, but it would disappear after the car got warmed up. Anyone have experience with timing chain failures on these cars? I have about 143,500 miles on the engine at this point.

843de

Boy, no compression on one cylinder does lead me to believe something happened to the cam chains, I haven't found too much on the "net" about chain failures in Ecotec engines....but anything is possible.

I would be hesitant about spinning the engine over excessively with a suspected broken timing chain, do you have any access to a fiber optic scope to look into the cylinders for valve movement or even broken valves?

firemangeorge

Pull the valve cover and take a look see.

springer.83

Depending on if the weather cooperates I'll be pulling the cover later this morning to inspect chain and valve movement. Unfortunately I do not have a bore scope for inspecting the cylinder internals.

springer.83

Well I have the valve cover off and the chain is still in once piece. No obvious damage to any of the components other than the top chain guide has a piece of the plastic clip broken on the front side.

I am attempting to check the timing, although I'm not sure about this specially colored link in the chain will still be different colored. I'm going out now to see about rotating the chain a complete revolution. Slow process when turning the alternator.

esmarkey

It sure sounds like a "jumped" timing chain issue. I used to have that happen on my older cars, but didn't think it would be an issue with the ecotech. How many miles do you have on her?

esmarkey

P.S. the Ecotech is a clearence engine so you shouldn't bend any valves turning it over if it is the timing.

ChevyMgr

Or the valve guide is loose in the cylinder head, which means a new one is needed.

springer.83

Well, after turning the timing chain through an entire revolution, I have managed to find two reddish colored links. I have yet to find a "unique" colored link.

The upper timing chain guide seems to have seen some wear, since the right side (front of car side) has the plastic "ear" broken off. The more I look at it the more it seems like it is a timing chain that has jumped. The car has ~143,500 miles on it.

Also, I thought that the Ecotechs were interference engines?