So, I have a 2011 chevy hhr that I believe has a 2.4l engine. It has a massive misfire. I'm talking car jerking, and recently it will stall after about 30 seconds idling in park. I recently replaced the camshaft sensor after the CE light came one, and when that was done it flagged the intake and exhaust solenoids, so I replaced those, then it flagged knock sensor, so I replaced that as well. The problem has just gotten progressively worse. Currently I have replaced all that plus put in new OEM plugs, as well as a new ignition coil for that cylinder. I have swapped it with both another plug and ignition coil just to determine if they were faulty and it still pops up cylinder 1. I'm at my whits end with this. I've heard it could be a bad injector, blown head gasket, compression issue. What would be the next logical step in trying to determine what's wrong. I'm about ready to just shop the thing even though I dont want to because I'd rather spend 40-60 for a part and do it myself then to pay someone alot of money to do it for me.

 

unplug the injector see what happens. you also should check the compression for all cylinders

 

Well changed the fuel injector and still had a miss so we did the compression test and it had 0 compression in that cylinder. So we did a wet test with alittle bit of oil and ran it and It had smoke coming out from the back end of the engine where the cylinder is at so only guess now is a blown head gasket.

 

could also be an issue with the valves. take the valve cover off and see if you see anything out of the norm compared to the other ones. generally speaking with a blown head gasket you should notice other issues like overheating,loss of coolant or white smoke in the tailpipe

 

How would the valves effect the compression of the cylinder though? It reads at 0 while the one next to it read like 180 I think. With the head gasket blowing outwards in that corner instead of in wouldnt it make more sense for just that cylinder to have no pressure without any other issues since air is just being forced out.......its parked for now and we plan on tearing it down Saturday weather permitting. Though maybe I'll pull the valve cover gasket later today since it would have to come off anyway but to be honest I wouldnt know what to look for.

 

well if you have a bent valve that wont seat fully that will cause it not to build pressure. or if something fell down into the valve preventing it from seating.

 

Guess I'll know Saturday when we tear the thing down. However when we did a wet compression test after the dry one the oil burnt up and smoke was coming out of the back corner of the engine which I'm not sure how that could happen unless the head seal went out.

 

yes that would make sense, i took the other post as a "theory" not the "hypothesis". good luck with her

 

Thanks, I'm sure I'm going to need all the luck I can get with the car. Really like it alot, it's a nice car so I'd hate to have to get something else.

 

if you want to test the valve train before teardown....put a vacuum gauge on the manifold....a needle dropping out consistently is indication of a valve problem...google vacuum gauge readings and you will see what to look for