2004 Cavalier 2.2L Ecotec no compression

cavalier
chevrolet

#1

This is my fathers car that I am working on for him. It is a 2004 Cavalier with the 2.2L 4 cyl engine. The car has been very well maintained and only has 80,000 miles. About a month ago, when you would start it, it would act like it was running on 2 cylinders and shake badly. If it was shut down and restarted the problem was gone. This happened twice and was taken to the dealership, they said it was the ignition coil, and it was common for the car to do this in cold temps, and not to worry about it.



Fast forward about 2 months, my dad leaves for a week, and the car is parked in the garage. When he returns, we try to start the car and nothing, acts like no spark. So we decided the coil finally died and replace it, only for it to act the same. We do a compression test and it comes out as an average of 75-100 psi in all cylinders. We figure it mightve jumped time, and needed a new chain. We take it down to the dealer to have them tell us whats wrong, and they just say it needs a new engine, and want 5000$. (real helpful) They also do a compression test and it comes out the same.



So we decide to just suck it up and replace the chain ourselves. I took the side and valve covers off, and the chain is in time. I figured maybe a bent valve, or bad head gasket, but when I pulled the head off the gasket looked fine, as do the valves and pistons. The engine looks like it has 5K. The only other thing I can think of is rings, but with only 80K I dont see how they could be bad? I am taking the head to the machine shop to have it checked out. What else could it be? Is it a common problem on these engines?


#2

The compression is bad, no doubt about it and it’s quite possible to have a ring problem in 8k miles, much less 80k.
Sludging, poor running which is washing the cylinder walls down, or an overheating episode can ruin rings quickly.

If the timing has not jumped then about all you can do now that the engine is partially diassembled it to check for leakage around the valves. Make sure they’re closed, turn the head upside down with the plugs in place, and add a liquid to the combustion chambers.
There should be extremely little or no leakage past the valves. If there is none and the timing is correct then it has to be rings.
This could have been determined with a wet compression test before the head was removed.

The original running badly upon startup may be nothing more than a fuel pump check valve which is leaking off and causing the loss of residual fuel pressure while the engine is at rest.


#3

Sludging, poor running which is washing the cylinder walls down, or an overheating episode can ruin rings quickly.

The engine has never had a sludging problem, has always ran great, and never overheated.

The original diagnosis after the coil wasnt the problem was the timing chain had broke or slipped, since it was an interference engine the head was planned to be pulled from the start to check the pistons. Like I said earlier it is being sent in and completely checked out.