From day one this Junkbalt ( as we affectionately nicknamed it ) has given us problems. Not some youngster beating the car (59 years old !!) From all the common problems -radio - brake sensor (took it back to dealer twice for the 2 problems. Still kept doing it. Told them what the problem was -but they put a band aid on major operation.Also told them if it was not fixed RIGHT- The next time they would see me is when I drive it through the showroom window and back to the service Dept )- chrome falling off interior handles - interior near impossible to clean - trunk lock won't open with key and more, to the reduced engine power, front lower control arm bushings, fuel filter,O2 sensor and of course MORE. The reduced engine power has been going on for 3 months.So it was disconnect the battery after you pulled to the side of the road ( Safety issue because it didn't always happen at a safe place to pull over.). Wait a few minutes then reconnect battery.It would start and power would be back for maybe a day or two and possibly as long as a whole week.I disconnected the battery for 24 hours and it was OK for over a month. Until the other day.It went to reduced engine power.Disconnected the battery a dozen times.No luck ! Started home ( only 4 miles away) at the break neck speed of 8 MPH. Had to stop at the Post Office.Made the mistake of shutting it off. A no start when I tried.Had to get it towed home. Car will not start and because the battery was disconnected there are no codes to be had.It is getting gas, but may have a weak spark.In the past year I replaced the coil pack, MAF sensor , lower control arm bushings, fuel pump,rotors, plugs, head gasket and probably a few things I forgot about.Anyhow, when you turn it over, it won't start.Now and then you hear a poof like it might want to do something.Then nothing but the starter turning it over.It is getting fuel. It seems to possibly have a weak spark (looks yellow) .There are 129,000 troubled miles on it. Fuel pump is wired direct because of the junk GM wiring harness.But fuel pump is working.At wits end with this car.I have considered possible sensor or a computer problem. Where should I start?

Crank position sensor if it won't start. Chances are it is not firing at the right time because it doesn't know where the pistons are.

Thanks for the tip.Will give it a try.

Good morning 56pontiac,
I'm sorry that your Cobalt left you stuck at the Post Office - were you able to look into the crank position sensor as Coby7 suggested? Any luck?

If I can look into anything (recalls in particular), please send me the last 8 digits of your VIN.

Regards,
Sarah
GM Customer Service

wouldn't crank position sensor stop the spark all together?

No it just sparks at wrong time, that is why you hear backfires and sounds like it's going to start.

Changed the crank sensor today. Still a no start. It is getting fuel and a spark. The spark is a yellow / orange color. After cranking it for about 10 seconds it "poofed" through the throttle body. Only did it once. The throttle body is dirty. I checked most of the fuses. Didn't check any relays. It is a brand new battery. I know the timing chain is suppose to be good for the life of the engine. But at 129.000 maybe it went.I should mention this is an automatic. All adult driven. Me and my REALLY REALLY old wife.This car has been trouble since day one. Talking to other Cobalt owners that have had a lot of the same problems as we did. None of them had the no start issue though. Heck my Nephew had his to the local Chevrolet dealer for an oil change and they forgot to put oil in it. They did say they would warranty the engine for as long as he owned it.But he hasn't had the electrical problems we have had. He had the usual lower control arm bushings, peeling chrome on the inside door handles etc. I have over $1,000.00 in parts already. (coil pack, MAF sensor,O2 sensor, head gasket (( and all the bolts etc that go with this problem )) fuel pump, lower control arm bushings, engine and trans mounts, rotors, battery & plugged cat converter .Plus the usual paint peeling on the door bottoms, interior that refuses to come clean. Gauges that don't work. But I put up with all of that. But this no start issue.

Not to piss on your parade but you have 129000 miles on the car. You did good for a GM product. I mean for sure some people get 200000 and more but those were usually driven all highway miles. You might not have a big problem, because it doesn't take much for an engine to refuse to start.

The piston alone can't hit the plugs, this means you dropped a valve or something and it hit the plug. These engines need regular oil changes and level checks. If you starve the timing chain oiler it will not be forgiving at all.

I should have pulled the plugs first thing. No doubt the timing chain. 2 plugs are smashed. So much for the timing chain being good for the life of the engine. This is where I part ways with GM. You buy a new car ( bought this new in 05 ) and figure no problems. But from the first weeks it was a problem. Worse part is, the dealership had to be told by me what the problems and solutions were.They couldn't figure out that a brake sensor was bad or the radios were junk. They luckily had a service tech who cam in while I was complaining. H went to the computer to look up if there were any notifications on it. He asked the desk jockeys if they ever check the updates on the computer. They said NO, we only go by the ones we have on paper. Money has it they couldn't read either !! Hopefully Ford or Chrysler will treat us better. The name JUNKBALT fits this car.

Cheapest route here if the rest of the car is in good shape is to get an engine from the junkyard. I've done 3 with my friend Chris since last september. The most we paid for an engine was 750$ and this was because it only had 12000Kms. 500$ for one with 84000Kms. 10-11 hours for the switch.