Asking the Mechanics for Help with 2008 Chevy HHR

[DDTSGM]

Yes, I drive a chic mobile when I'm not in my truck. Much better mileage.

Anyways, the HHR has a fresh factory re-manufactured engine in it (long story). Shortly after I got it back the check engine light came on while I was driving in town, several moments later when I looked, it had reset, then it came back. It was a weekend so I ran to Auto-Zone and read the code - it showed an intermittent misfire in #1 and suggested new plugs or a coil pack. Since the plugs were fresh, I figured coil pack and decide what the heck, replace them all. It reset for a bit them came back on, so I checked it again, same code.

At this point I pulled the plugs and #1 looked a little oily to me. So, I took it back to the chop that had replaced the engine. They check compression, plugs, injectors, etc, did a factory reset and the mechanic drove it around with their scanner hooked up. No problem. They also told me that they had placed #1 plug in #2 hole so that if it threw the code again and it was #2 they'd know it was the plug.

Today, 47 miles after the service it threw the same code. I forgot to add that at several points the check engine light started flashing and it was running rough while stopped at a light, returned to non-flashing as I pulled away from the light, which indicated to me that a cylinder wasn't firing.

At this point, I'm paying for whack-a-part. What would be the next step?

[fixer]

What did they do to check injectors?

Did the plugs get replaced?

I've seen new plugs be defective with the ceramic/porcelain cracked and it wasn't noticed during installation. after a few miles driving the carbon tracking was pretty obvious. And the misfire was random.

I would try a new set of plugs with the right heat range and factory part number then go from there.

Basically...

if data is not showing major corrections on fuel trim, but a misfire is still being flagged, and you are getting symptoms of a misfire on only one single cylinder, then there might be a deeper mechanical issue.

Compression tests are good to get a quick understanding of any major issues. A leak down test can indicate a more certain test of "compression integrity".

Was the cylinder head replaced with the engine?

[farscott]

If there is oil on a spark plug, a gasket or seal is a culprit. I would check the valve cover gasket as that is a known issue with the HHR engines.

[AKDoug]

If there is oil on a spark plug, a gasket or seal is a culprit. I would check the valve cover gasket as that is a known issue with the HHR engines.
I don't know anything about HHR engines, but lots about other engines. Why would a valve cover gasket be a culprit on an internal engine issue? Head gasket I could see.

Misfiring is going to be ignition, fuel delivery, compression or contamination. You've already ruled out ignition. Injector function needs to be checked, compression and leak down need to be checked, and head gasket needs to be checked.

[Erik]

As far as I can tell from the OP, ignition hasn't been ruled out - just a bad plug. Could still be the coil pack or wires. Could also be something internal to the PCM, which can be much harder to diagnose or the wiring harness. Let the shop follow up on the diagnosis unless you don't trust them. They should be able to test the coil pack and pull the plug again to see if it's oily. A random intermittent issue like that doesn't sound like a gasket; more like a loose connector, bad sensor, bad ignition component or wiring. From a die hard GM guy: GM electronics suck.

[0ddl0t]

Oily plugs concern me, especially on a brand new engine. Is the plug fouled again now?

What caused the original engine failure?

[JRB]

If it's still the same #1 code and the coil pack and plug have been replaced, and the code is coming back that quickly, as fixer already stated it's time to move an injector to another cyl like they did with the plug and coilpack on #2. An injector is the best case scenario here.

Start with a leakdown test on all four cyls and see if #1 is low. Compression tests can find big problems but on a poorly rebuilt engine I've seen decent compression but poor leakdown if something got screwed up with the ring gaps or cyl hone or whatever. At which point it's time to start a warranty claim on that reman motor. Oily plugs have me leaning this way, unfortunately.


If the leakdown and compression are both good and the injector swap doesn't move the problem, try an intake leak test/smoke test/etc to see if there's a small intake manifold leak in the runner to cyl #1. Typically that would throw CEL's for other things too like MAFS values read by the PCM being out of wack, but with the short duration of your PCM resets they might not have had time to 'fail' enough to throw their own CEL. I don't expect this to be the case, but it's a possibility that's easier than replacing the whole engine.

Easiest way to do DIY that test is get some flammable brake cleaner and spray a short squirt the gasket seams of each runner as the engine is idling. If the idle goes up briefly when you hit a spot, you know there's a leak at that spot. Only downside is on inline engines you it's usually a PITA to get to the underside of the intake manifold to accurately hit the underside of each runner, but getting to the top of each runner tends to get the injector seals as well as 70%-80% of the whole runner by proximity. It's just not a perfect


I don't know anything about HHR engines, but lots about other engines. Why would a valve cover gasket be a culprit on an internal engine issue? Head gasket I could see.

Misfiring is going to be ignition, fuel delivery, compression or contamination. You've already ruled out ignition. Injector function needs to be checked, compression and leak down need to be checked, and head gasket needs to be checked.

Oil that leaks into the spark plug valley on a DOHC engine can get in between the plug and plug wire or coil pack. The added resistance is sometimes enough to cause a misfire or spark blowout under load on turbocharged engines.

[DDTSGM]

Thanks to all.

Yes, the head was replaced, it was not a short block. That being said, the ignition components are all 12 years old and have been removed and replaced couple times.

Yes, I trust the shop, I tend to keep vehicles a long time and they have done some major work for me with no complaints, and, it's a long story, but they treated me very good on the engine replacement deal.

ETA: They checked the injectors, did compression, don't know about leak-down as I didn't keep the receipt (dumbass).

Right now I'm focusing on ignition as the source. I'm fairly comfortable with non-electronic, cam-in-block, carburetor engines; over my lifetime I've rebuilt and or replaced several. I'm definitely out of my depth with this ignition system.

At this point I was thinking my next step might be to replace the ECM-PCM, but that is getting a little to pricey to be playing process of elimination.

Don't know if it is related, but right before this happened, my automatic power door locks stopped working, I replaced the fuse, worked for awhile then it popped again.

[DDTSGM]

Oily plugs concern me, especially on a brand new engine. Is the plug fouled again now?

What caused the original engine failure?

Timing chain slipped.

[AKDoug]

Oil that leaks into the spark plug valley on a DOHC engine can get in between the plug and plug wire or coil pack. The added resistance is sometimes enough to cause a misfire or spark blowout under load on turbocharged engines. Copy that, as I said I'm not familiar with that engine. You would think, though, that they would have caught that if changing the plugs.

[cornstalker]

Thanks to all.

Yes, the head was replaced, it was not a short block. That being said, the ignition components are all 12 years old and have been removed and replaced couple times.

Yes, I trust the shop, I tend to keep vehicles a long time and they have done some major work for me with no complaints, and, it's a long story, but they treated me very good on the engine replacement deal.

ETA: They checked the injectors, did compression, don't know about leak-down as I didn't keep the receipt (dumbass).

Right now I'm focusing on ignition as the source. I'm fairly comfortable with non-electronic, cam-in-block, carburetor engines; over my lifetime I've rebuilt and or replaced several. I'm definitely out of my depth with this ignition system.

At this point I was thinking my next step might be to replace the ECM-PCM, but that is getting a little to pricey to be playing process of elimination.

Don't know if it is related, but right before this happened, my automatic power door locks stopped working, I replaced the fuse, worked for awhile then it popped again.

I would definitely not throw a PCM at it. Certainly not without testing it properly first.

Was the #1 plug oily on the porcelain above the threads or oil fouled on the electrode?

Just as a data point, I have received and installed a 4.3L Goodwrench crate motor that they forgot to install valve seals on one cylinder, causing oil-fouled plugs. That one got towed to the Chevy dealer and fixed under warranty there.

Also a Chevy 5.7L Jasper engine that fouled the plug badly on one cylinder. This one belonged to the owner of the company I work for. Jasper never made good on it so the owner put the truck out at his house to use around the property and carried a spark plug and a wrench with him all of the time. Needless to say, Jasper has lost our business forever.

Most recently, an ATK reman 5.7L Hemi that burned over a quart of oil in 700 miles. After a few tests, LKQ replaced the engine without a hassle.

Every one of the faulty engines listed above passed compression and leak down tests.

I guess all of that is a moot point if the oil was on the porcelain in your case.

[noguns]

If you trust the shop, them you should trust what they recommend next.
How did they check the injectors? Did they move one to another cylinder and check if the misfire moved to another cylinder?
I've seen countless things cause misfires. Loose electrical pin fits or backed out pins. Pcm. Software updates. Chewed up wiring.
I've had bad valve springs that would even give good compression and leak down readings.
Vehicles with direct injection can cause carbon build up enough to cause misfires in under 15k miles.
The current cars have so much that can go wrong. Sometimes the process of elimination is all you can do. A really good shop can use an engine analyzer and check ignition and fuel voltages with the vehicle running, but that is almost a lost art now. Most mechanics are likely to throw a bunch of parts at the car that are the "most likely" cause.

[fixer]

Thanks to all.

Yes, the head was replaced, it was not a short block. That being said, the ignition components are all 12 years old and have been removed and replaced couple times.

Yes, I trust the shop, I tend to keep vehicles a long time and they have done some major work for me with no complaints, and, it's a long story, but they treated me very good on the engine replacement deal.

ETA: They checked the injectors, did compression, don't know about leak-down as I didn't keep the receipt (dumbass).

Right now I'm focusing on ignition as the source. I'm fairly comfortable with non-electronic, cam-in-block, carburetor engines; over my lifetime I've rebuilt and or replaced several. I'm definitely out of my depth with this ignition system.

At this point I was thinking my next step might be to replace the ECM-PCM, but that is getting a little to pricey to be playing process of elimination.

Don't know if it is related, but right before this happened, my automatic power door locks stopped working, I replaced the fuse, worked for awhile then it popped again.

Ignition is the cheapest and easiest thing to try at this point.

[cornstalker]

I wouldn't start throwing parts at it either. That will just create more crap for the diagnostic tech to wade through.

A good quality scanner should allow the tech to watch injection and ignition PIDs while the misfire is counting. If those look normal and they need to check for valvetrain problems a vacuum transducer can be used to measure and graph positive and negative pressure pulses in the exhaust, and would likely reveal a valve/valve spring problem.

As previously mentioned, pushed out pins in harnesses are frequently a culprit on an engine swap. I would think the PCM would have been counting misfires before it left the shop the second time. Similarly, it should have been counting misfires immediately with a valvetrain problem.

[DDTSGM]

I wouldn't start throwing parts at it either. That will just create more crap for the diagnostic tech to wade through.

A good quality scanner should allow the tech to watch injection and ignition PIDs while the misfire is counting. If those look normal and they need to check for valvetrain problems a vacuum transducer can be used to measure and graph positive and negative pressure pulses in the exhaust, and would likely reveal a valve/valve spring problem.

As previously mentioned, pushed out pins in harnesses are frequently a culprit on an engine swap. I would think the PCM would have been counting misfires before it left the shop the second time. Similarly, it should have been counting misfires immediately with a valvetrain problem.

Taking it back in later today. Stopped by this morning and got a copy of the receipt, this is what they have down:

Performed compression test on all cylinders: 1) 170; 2) 190; 3) 190; 4) 190. Tested injectors on cylinders #1 and #2, both have about 12.5 ohms. Checked connections at connectors for injectors with noid light, all testing good. Swapped plugs on cylinders 1 and 2 around. Test drove car and watched live data. Have no misfires.

Engine was installed at 131,536. Current mileage 131,792.

So, a little concerned at differences in compression.

[farscott]

Oil on plug and low compression in same cylinder. Ignition looks good. So bad gaskets or a structural issue. Time to tear it down or replace it.

[Hambo]

Engine was installed at 131,536. Current mileage 131,792.


If I'm reading your OP correctly, it hasn't been right since it was installed. Is there any warranty on the engine?

[0ddl0t]

Taking it back in later today. Stopped by this morning and got a copy of the receipt, this is what they have down:

Performed compression test on all cylinders: 1) 170; 2) 190; 3) 190; 4) 190. Tested injectors on cylinders #1 and #2, both have about 12.5 ohms. Checked connections at connectors for injectors with noid light, all testing good. Swapped plugs on cylinders 1 and 2 around. Test drove car and watched live data. Have no misfires.

Engine was installed at 131,536. Current mileage 131,792.

So, a little concerned at differences in compression.

Yeah, I'm sure they'll take care of it. When a rebuilt engine has issues, it is usually apparent right away.

[fixer]

Taking it back in later today. Stopped by this morning and got a copy of the receipt, this is what they have down:

Performed compression test on all cylinders: 1) 170; 2) 190; 3) 190; 4) 190. Tested injectors on cylinders #1 and #2, both have about 12.5 ohms. Checked connections at connectors for injectors with noid light, all testing good. Swapped plugs on cylinders 1 and 2 around. Test drove car and watched live data. Have no misfires.

Engine was installed at 131,536. Current mileage 131,792.

So, a little concerned at differences in compression.

Ohms on injectors is half the story. Need to check spray pattern.

That said I don’t think leaky injectors are the issue because you’d be seeing fuel trim codes and o2 codes.

The compression test is strange. A 10 % difference on a rebuilt motor is not good.

Maybe piston rings not set up right. Could also be valve seats or guides.

[DDTSGM]

If I'm reading your OP correctly, it hasn't been right since it was installed. Is there any warranty on the engine?

3 years or 100,000 whichever comes first.

[camel]

I’d start focusing on that warranty. At the least that motor needs is a headjob.

[DDTSGM]

The compression test is strange. A 10 % difference on a rebuilt motor is not good.

Maybe piston rings not set up right. Could also be valve seats or guides.

Kind of what I thought. Mentioned it to them and they agreed.

I think if it needs to be replaced they would do it since I'm not in a hurry to get the vehicle back, and it will keep one of their mechanics on the clock covered by warranty, correct?

[noguns]

As mentioned before, ohm readings are not always helpful.

The shop should have moved injectors to see if the misfire would move to another cylinder.

[0ddl0t]

I think if it needs to be replaced they would do it since I'm not in a hurry to get the vehicle back, and it will keep one of their mechanics on the clock covered by warranty, correct?

Around here the engine would be replaced for free by the rebuilder and the shop would eat the labor (something the shop bakes into the price you pay up front).

[DDTSGM]

Around here the engine would be replaced for free by the rebuilder and the shop would eat the labor (something the shop bakes into the price you pay up front).

That is where it gets interesting - this engine was paid for under warranty because a timing chain failed within it's warranty period.

The deal I was offered was a used engine with one year warranty for free, or a rebuilt engine with 3 years or 100,000 for the difference in allowed price - roughly a thousand dollars.

[fixer]

Dan Lehr,

Any updates on this?

[DDTSGM]

Dan Lehr,

Any updates on this?

Yes sir.

Replaced #1 injector. I've driven it almost 250 miles since I got it back with no troubles.

I'm going to take it back in a week to have compression checked again. Theory is that injector was flooding cylinder with enough gas that it was cleaning the oil of the cylinder walls enough to get the lower reading.

Not sure I buy that but, we will see.

ETA: they had it two days the last time, did a smoke test and further checking of injectors.

[fixer]

Yes sir.

Replaced #1 injector. I've driven it almost 250 miles since I got it back with no troubles.

I'm going to take it back in a week to have compression checked again. Theory is that injector was flooding cylinder with enough gas that it was cleaning the oil of the cylinder walls enough to get the lower reading.

Not sure I buy that but, we will see.

ETA: they had it two days the last time, did a smoke test and further checking of injectors.

With no 02 or fuel trim codes? That’s really hard to imagine.

If it was leaking that bad you’d also have contaminated lube oil and the top of the piston would look totally cleaned off.

[DDTSGM]

With no 02 or fuel trim codes? That’s really hard to imagine.

If it was leaking that bad you’d also have contaminated lube oil and the top of the piston would look totally cleaned off.

Don't know anything about the code things.

At this point it is running good - drove about 75 miles today - I'll check the oil tomorrow, hadn't thought of that.

[fixer]

Don't know anything about the code things.

At this point it is running good - drove about 75 miles today - I'll check the oil tomorrow, hadn't thought of that.

Honestly hoping earnestly it is a bad injector and my hypothesis is bunk.

Perhaps the piston rings seated in and it was just a poor performing injector

[0ddl0t]

Theory is that injector was flooding cylinder with enough gas that it was cleaning the oil of the cylinder walls enough to get the lower reading.

Not sure I buy that but, we will see.

Sounds plausible. Crossing my fingers for you...

[Spartan1980]

Are you losing any coolant? Had a head gasket or cracked head throw misfire codes and it also took out a couple of catalytic converters slowly. That should have been my clue. Well, that and the slowly disappearing coolant. The car had 247k on the clock so I called it done as the repair was the value of the car. '02 Monte Carlo SS which were known for gasket issues due to Dexcool coolant.

[DDTSGM]

Are you losing any coolant? Had a head gasket or cracked head throw misfire codes and it also took out a couple of catalytic converters slowly. That should have been my clue. Well, that and the slowly disappearing coolant. The car had 247k on the clock so I called it done as the repair was the value of the car. '02 Monte Carlo SS which were known for gasket issues due to Dexcool coolant.

No coolant loss. Oil looks good.

[JohnO]

My wife's 2013 Honda Odyssey van is at the dealer for a cylinder #3 misfire. P0303 code. The spark plug in cylinder #3 was fouled. Initially I swapped the coil with cylinder #2 and reset the code. The problem didn't move. Remedy is new piston rings. Apparently this is a known issue and is being covered under warranty. I was told the initial 6 years or 60K miles warranty has been extended to 8 years unlimited miles for this particular issue.


American Honda is announcing a powertrain warranty extension as a result of a settlement of a class action captioned,
Soto et al.v. American Honda Motor Co., Inc., Case No. 3:12-cv-1377-SI (N.D. Cal.).
The piston rings on certain cylinders may rotate and align, which can lead to spark plug fouling. This can set DTCs
P0301 No. 1 cylinder misfire detected, P0302 No. 2 cylinder misfire detected, P0303 No. 3 cylinder misfire detected,
P0304 No. 4 cylinder misfire detected, and cause the MIL to come on.
American Honda is extending the powertrain warranty to cover repairs related to engine misfire (that triggers DTCs
P0301 through P0304) to 8 years with unlimited mileage from the original date of purchase and has settled a class
action based on this remedial measure.

[fixer]

My wife's 2013 Honda Odyssey van is at the dealer for a cylinder #3 misfire. P0303 code. The spark plug in cylinder #3 was fouled. Initially I swapped the coil with cylinder #2 and reset the code. The problem didn't move. Remedy is new piston rings. Apparently this is a known issue and is being covered under warranty. I was told the initial 6 years or 60K miles warranty has been extended to 8 years unlimited miles for this particular issue.

Yeah I was thinking of something like this. The rings were lined up causing fouling. Now they have rotated enough to seal up.

Or perhaps they needed a few extra miles to seat in to a good wear pattern.

[JohnO]

Yeah I was thinking of something like this. The rings were lined up causing fouling. Now they have rotated enough to seal up.

Correct me if I am wrong but shouldn't piston rings be very much like gas rings on an AR bolt and when in place inside the cylinder or carrier the individual ring gaps closed and position inconsequential?

[0ddl0t]

Correct me if I am wrong but shouldn't piston rings be very much like gas rings on an AR bolt and when in place inside the cylinder or carrier the individual ring gaps closed and position inconsequential?

The rings are never fully closed. Ideally you stick new rings in their specific cylinder without a piston and measure their gaps to check against the specs (and then take them out & file the gaps larger if necessary).

https://www.onallcylinders.com/wp-content/uploads/2015/07/Gap-3-600x400.jpg

You always want some gap to allow for thermal expansion and to leave a little wiggle room for minor overheating so the engine doesn't seize.

[fixer]

Correct me if I am wrong but shouldn't piston rings be very much like gas rings on an AR bolt and when in place inside the cylinder or carrier the individual ring gaps closed and position inconsequential?

Along with @oddlot post... there are two compression rings and a pack of oil control rings and a scraper.

Ideally the gaps are 180 off from each other.

If the ring gaps happened to be close to lined up there might be a slight loss of compression and also loss of oil into cylinder.

Assuming the rings were lined up of close to lined up on a ring gap, they may have rotated a slight amount and sealed up. It could also be a wear-in phenomenon or possibly the gap was too big for the cylinder and with some miles and slight carbon build up the system sealed up.

[JohnO]

Thanks guys! Makes perfect sense.