2007 Chevy HHR... It will turn over, but not start. Checked the fuses, plugs, battery connections ... nothing. My son needs this car for college at the end of the month.

 

Nicole, welcome to the site, check the ground wire connections at the transmission down to the right of the oil filter housing,
Did anyone try to jump start the HHR, be very careful to only connect at the red positive terminal at the fuse box under the hood and the ground nut at the driver's side strut tower, if this was not followed re check the fuse box.
How old is the battery it maybe time for a new one, when they go they are gone, deader than dead, I had the same issue 4 years ago

 

Add the fuel pump to the list of things to check - there should be fuel under pressure in the fuel rail, and you should be able to briefly hear the fuel pump start up when the car is first turned on, just before it cranks.

 

Welcome to the site

As long as it cranks over good I would check the fuel pump.

Best way is with a psi gauge on the fuel rail.

I have gotten cars with a bad fuel pump started by hitting the fuel tank with a rubber mallet while someone is cranking the engine with the key. It is not a fix but may help with the diagnostic.

 

When a problem like this pops up always, always do two things. First, ask yourself what you did in the last day or so. As noted above something like jump starting may have done something. Second, go back to basics. Do you have fuel and spark? These things require new tools. You will need a noid light to make sure the injectors are firing, a fuel pressure gauge to check for fuel pressure and a scanner to check for codes. Unless you are into old cars everything you own can use these NEW basic tools. I got a scanner that will read up to 85 different things, display codes, clear codes, warn of pending codes and data log. All this for $85. I was getting a lean condition code on another car and could not figure out why. Then I looked at the long term fuel trims and found the problem.

 

It's getting spark & gas. Sounds like their is compression... like it almost wanted to start.

 

If it has fuel and spark the next thing to check would be a compression test.

It is possible that the timing chain jumped time. How many miles on it?

Was there a chain noise before it quit running?

 

not that I know of ..but it was my inexperienced 18 year old that was driving it. He was backing it up at 3 a.m. He would not have noticed. We are hoping that it did not jump timing.. 101,000 miles Code: p0449 came up. but that wont stop the car from starting, correct?

 

It might, depending on the cause. Teenager backing up in the dead of night may have hit the EVAP box or wiring on something. I was a teenager once.
P0449 Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction

and:P0449 Chevrolet Evaporative Emission Vent Valve Solenoid Malfunction OBDII Engine Light Trouble Code | Engine-Codes.com

It could indicate an electrical problem. Start at the fuse box, check all of the grounds and all of the hots. I'm kind of thinking something in the fuse box.

 

well, he just found out that the tensioner must have gone bad. When he was checking the chain he quickly noticed it was not just lose, but hanging... looks like the timing slipped after all. I just hope he can fix it. At least it was going super slow when it happened, and does not seem like anything else was damaged.