Ok guys so here are the facts, My girlfriend was driving her 04 cavalier with no problems and stopped for gas. She put some gas in her tank and started to drive off and her car died. She has a tendency to drive her car till the gas light turns on. So i figured her fuel pump finally went out like I told her it would if she kept doing that. I asked her if her car made any noises or anything when it died and she has no clue. It has spark, and I pulled the fuel rail to see that the fuel injectors pulse.When I checked for fuel pressure it primes at about 28psi and at second prime it goes to 55psi and holds. I was thinking it had a weak pump and was planning on replacing it though I wanted to check compression first. When I checked the compression there is NO compression at all!! It will jump up to 30psi and drop straight down. I pulled the valve cover, and the timing chain is taught and everything looks good. I am thinking head gasket, but I find it very odd that it would just blow out on all cylinders like this. By looking through the spark plug holes the pistons look in good condition and I see no debris. I'm just trying to get some opinions on what you guys think. I am not to familiar with the ecotec motors and any advice or help would be greatly appreciated!

-- Greg

I know the earlier ecotecs are notorious for timing chains... I don't know if that's what is affecting hers, but it is likely.

The timing chain is still in tact and very tight. I did read that while looking for information. I know this would cause no compression in all cylinders, though find it hard to believe it would jump a tooth while being so tight

Not likely a timing problem if you say the chain is there and tight. Not trying to dis your knowledge but you did do the compression check correct right? All plugs out, foot to the floor, listen for 4 "poofs"? (theres other stuff to it but those can cause false readings if not correct)

Not real sure what else could cause those symptoms, it would have to jump an aweful lot of teeth to produce those reading. Do you have the cam cover off to see the chain? If so does everything else under there look good? Both cams tight and such?

-Joe

Non return pressure valve on the compression tester defective. Or...did you have your finger on the pressure release button?

[This message has been edited by fierofetish (edited 06-04-2012).]

Thanks for the advice guys! Its actually a brand new compression tester so I hope its right...everything looked in order with the valve cover off. After continuous checking compression I did find that at certain spots of the chain it became very lose. It doesnt look like it was getting enough oil and is sticking in areas. Tomorrow I'm going to pull the head and hope that the valves didnt get messed up. That would really be a bummer! I figure if they did it would almost be cheaper to get a used engine to put in it then buy a timing chain kit, reconditioned head, head studs, and gaskets. Plus doing timitng is not a very good strenth of mine..

Maybe your compression tester is different to mine? They are meant to maintain the needle at the highest compression it reads...and to be honest, I have always found that the real compression is shown after the engine has been turned over a few revs, not just one. So the part I don't understand, is how can the compression tester register 30psi, and then drop to zero without opening the reset valve? It is usually a Little silver 'button' just at the base of the meter, and you have to press it to reléase the recorded compression on the gauge, to zero it again.

Roll the motor over by hand. My timing chain was stretched at a link section. Felt tight rolled over a few times and the chain went slacked. its not the timing chain that fails its the tensioner on the car. I just did my chain cost 600 in work to get all my intake valves replaced. also Feel the rockers them selves. I played with mine and they fell off even when the chain felt tight. I know a new engine may be cheaper but look at it this way you know your motor that used motor you have no clue how hard it was beat. On jbody.org there are alot of Illinois members maybe you can find one to help you out.

[This message has been edited by Tstang429 (edited 06-04-2012).]

Maybe she accidentally put Diesel in the tank... hehe

HAHAHA it wouldnt suprise me if she did put diesel in it! I appreciate all the help! I actually went to school for automotive, and work in a shop. But am still learning, I actually just got home from a 10.5 hr day doing a turbo/intercooler setup on a 240 with a full silvia drivetrain, and timing belt and water pump on a civic. So I know how to use a compression tester correct, I have done several. but thanks for making sure After turning the engine over more for testing the chain did end up going slack and when I had my girlfriend jump in the car and crank it over it was basically throwning the chain up and over the intake cam gear. I will checked to see if the valves are fully up at TDC though I hate to say that they are ok with out seeing them... Im more of a visual person. As soon as I get another day off... ill get to not have a day off and work on another car... But I will keep you guys posted, and thanks again for all the imput!

The chain jumped....