cylinder 1 misfire. low compression
 

So, I have a 2009 hhr 2.4 liter engine. For a while now this had been happening intermittently but now is pretty much constant. Rough idle, runs rough but smooths out a little at higher speeds. Dealership checked it out and says cylinder 1 had low compression and they want $1500 to take it all apart and they said it may end up being more depending on what the issue is, the price just starts at 1500. It only has 80,000 miles on it but my 5 year warranty expired a few months ago. Is there anything I can do? Before we took it in we got new plugs, new coils, new injector. Also in have to push the gas to get it to start. Is that just a symptom of low compression? How do these things happen with a well cared for car with so few miles??

:welcome8: to the forum, wish it was under better circumstances.

Well a dead cylinder/low compression on a particular cylinder can have many causes.

Among them are:

* A blown head gasket.
* A cracked cylinder head.
* A burned valve.
* Broken piston rings or a broken piston.
* A bad or loose valve seat.

And the list goes on.

Now before they pull the cylinder head, you might want to see if their tech can use a borescope to look into the affected cylinder. It won't prevent the inevitability of an engine tear down, but the tech may be able to spot the problem and narrow things down.

Rough running, poor idle quality, hard starting, are textbook symptoms of a dead cylinder. And the engine will smooth out at higher speeds because the firing events in the three "good" cylinders are masking the loss of the non-firing cylinder.

If you have a printout from the dealer showing the compression readings across all four cylinders, post the numbers up in your reply. We know what a "healthy" Ecotec engine should show on a compression test.

And to answer your last question, engines can fail with even the most meticulous care, while other engines suffer the most egregious abuse...and they'll purr along for hundreds of thousands of miles without complaint.

Of course, as with doctors, you can always take your HHR for a second opinion.

Welcome to the site! I noted you had plugs, coils, injectors replaced was this under warranty? I wonder if they were chasing rabbits and throwing parts at it and now want to perform the big job and recoupe some of their cash.
I concur with 843de , please post those compression numbers.
I would also get a second opinion from a reputable shop as these start price could be more once we open it up, jobs always sound fishy to me.

No Check Engine Light? With that many misses I would expect a code P0301. Which would make me suspect injectors or coils.

Why did you change injectors and coils? (before a compression test)
What did the old plugs look like?

Well we did all of that first because it was stuff we could ourselves. Did not have a compression tester. I get a code of 301 and 172 which says its running rich. I will have to hunt around for the compression results. I cannot recall the other 3 but I'm pretty sure cylinder 1 was at 55. They did not do a wet compression. Just the one test and then came back and suggested the tear down. Ugh....

I may have destroyed some valuable evidence, but we changed the plug almost certain it was the problem and that this was a simple solution. We looked it over and it looked darker than the rest but we didnt exam it that thoroughly and then tossed it.

So any coolant in the oil? Or oil in the coolant? How about the coolant level? Please check these now in today's time , to confirm and we can go from there.
Just to confirm were is the car , your place or the dealers?

55 in cylinder 1 sounds like internal damage. A new plug won't fix that.

Run a borescope and take a look. If you find something or not, sounds like the head will still need to come off either way.

Wouldn't buying a $30 compression tester have been cheaper than injectors and coils?

And p0172 does not MEAN rich. Google. The code then read a few of the links, then you will begin to understand. Maybe save some money,too.

Oh well.

The car is here with me. Again, we didn't jump to a compression test BC we checked ignition and fuel first. I assumed major mechanical failure was less likely than the more common problems.

I'm not understanding about 172. It says in the book the system is too rich. It smells pretty bad when its running (I thought this was an indication the car was running rich as well).

I will head out and check everything else and get back to you in a few.