2017 Camaro SS LT1 Misfires - Dealer Can't/Won't Fix

Snrub said:Paying the tech's based on piece work is a lousy system in terms of how it affects the customer.

I wholeheartedly agree.

We were recently switched to this setup, and I am going to have a chat with my employer next week about this.

RIght now I have a problem child at work.  I have maybe 12 unbillable hours of diagnostic time in it. (Unbillable unless you feel comfortable with giving someone a a $1500 charge for "elifino")  The flat rate way to have addressed the car would be to load the parts cannon and say it needed everything even peripherally related to the problem.  This is not proper diagnostics and it is not good customer service.  (And of course, under warranty, this would not fly)

On the other hand, last week I have 1.72 billable hours, because that car was essentially also the only thing I had to work on all week, and it made me so frustrated and depressed that it made me consider setting fire to MY own [redacted] out of spite.  From a personal standpoint, I'd have been just as well to load the parts cannon, and if they bought it, then I'd have something to do and maybe the car would be fixed.  And if they didn't buy it, then berk it, not my problem.  (Again, this would be horrible customer service)

One of the reasons why I left my job at a dealership, incidentally, was because I was being guided to not repair vehicles under warranty.  Granted, warranty paid roughly 60% of what customer-pay services were, but at the same time it was still pay, and besides, in my mind (then and now), people buy a new car for the warranty, so it is bad customer service to avoid warranty repairs.  (Specifically, we were having a problem with the rack and pinions failing in a way that was making the power steering pumps loaded all the time.  I was told to stop doing so many warranty racks, even though people were coming in complaining about underhood whine and I knew damn well what the problem was...)

well don't do this no matter how tempting.

a year and a day in the pokey.  Federal style. 

In reply to Knurled. :

This is fascinating for those of us who don't work in the business. Thanks for sharing. It must be incredibly frustrating to deal with this at your office. 

As for the OP, I don't know about Canada but in the states we traditionally deal with situations like this with a lawyer. Nothing else short of sending a personal letter to Mary Barra will get your customer service unstuck at GM.

OEM calibrator here,  I work for the competition, so take my word with a grain of salt. But I have a reasonable understanding of how modern engines work. Read through the whole thread, sorry to hear about your issues. I appreciate your persistance with diagnosis, it is likely better left to GM corporate.

I have a few theories though. Do the misfires go away during cold start or WOT? That would indicate a bad O2 sensor, because most cars go open loop (no feedback from O2 sensors) under these conditions. Unlikely, since both banks are affected, but possible.

I think leaky injectors is also highly unlikely, especially because all 8 of them are effected. Plus, fuel trims should be able to compensate for the extra fuel, unless the injectors are so bad they stay open. Again, unlikely as the vehicle wouldn't run at all then.

I'd be suspicious of VVT, if the cams aren't being timed right these issues can take place. All 8 affected, inability to control AFR, catalyst efficiency issues. 

Also possible is timing. I've seen issues with bad crankshaft position sensors, or bad tooth wheels causing huge issues. If timing is shifted from hardware issues, then spark, fuel timing, and VVT will be effected and wreak havoc on an engine. 

Feel free to shoot me an email if you want to chat about it more.

In reply to whiskey_business :

Apologies if this is already what you're aware of, but would any of that really be the case given that this is a directed injected, single cam engine?

VVT issues should, at worst, result in a MAF error, although they are pretty good about cam/crank correlation diagnostic on anything VVT.  Heck, even pre-VVT.

If the fuel injectors are indeed dribbling, wouldn't they be introducing poorly-atomized fuel all the time, even during the exhaust stroke?   That would play hell with O2 readings if there was an afterburn happening, especially if it was already running lean because the computer was pulling fuel away due to the O2 readings...

My SIL bought a new Chevy Equinox in 2012 and had a dealer installed sunroof put in which rattled from day one. She had the car in to the dealer numerous times for 2 years or so with no luck on a fix. She ended up relating the story to her daughter's husband's dad (huh?!) who is in the corporate world and offered to help by composeing a letter and sending it to someone at the dealership. They fell all over themselves trying to fix the sunroof. Done deal. Easier to deal with a retired school teacher than some corperate dude who's going to legally chew your ass, I guess. The point of all this is that there is a way to put the fear of the Lord in these turkeys. I couldn't do it- I'm not savvy that way, but I know people who can if the situation comes up with me, I think.

In reply to Knurled. :

VVT issues can have a huge impact, even with a DI and single cam engine, as it changes combustion characteristics. Lots of other engine functionality (spark, fuel, throttle position) get scheduled based off of cam phasing. Probably less effect on a single cam engine, since you can't change intake and exhaust timing independently, but still has a huge impact on engine stability. I agree that it should get caught by the monitors, but it might not.

As far as injectors go, I've never seen DI injectors leak that substantially, they are supposed to seal up to huge pressures. You are correct that dribbling fuel especially during exhaust stroke would skew AFRs.

I'm not sure dribbling fuel during the exhaust stroke would do much to the O2 sensor readings.  Remember, they read oxygen content, not fuel.  That's why an engine with a misfire will show lean on a wideband (due to the extra air in the exhaust from the dead cylinder, it ignores the raw fuel). 

Lets see if the problem is gone after the new convertor is installed.  If it is not gone then they will have to find the cause of this miss fire or another convertor will be needed in the future.Possibly when the convertor is removed they can maybe look inside to see if any damage is seen.Melted/oil fouled who knows.Rember the convertor was damaged by some thing.Hopefully something that has already been repaired in your previous visits

rslifkin said:

I'm not sure dribbling fuel during the exhaust stroke would do much to the O2 sensor readings.  Remember, they read oxygen content, not fuel.  That's why an engine with a misfire will show lean on a wideband (due to the extra air in the exhaust from the dead cylinder, it ignores the raw fuel). 

That assumes that everything is equal on that bank.  They are not controlling cylinder to cylinder.  If one or two cylinders are rich, the whole bank gets fuel pulled away, even the good cylinders.  Then you get some cylinders running lean, and misfiring...

I've seen weirder things happen.

roto_b_racing said:

Lets see if the problem is gone after the new convertor is installed.  If it is not gone then they will have to find the cause of this miss fire or another convertor will be needed in the future.Possibly when the convertor is removed they can maybe look inside to see if any damage is seen.Melted/oil fouled who knows.Rember the convertor was damaged by some thing.Hopefully something that has already been repaired in your previous visits

Who is replacing a convertor?

I cant' see replacing a convertor doing anything useful.  The first rule of convertors is that they don't die, they get killed.  The second rule is that the PCM/ECM can not properly monitor the convertor if there are misfire, O2 sensor, or fuel trim issues.  Those need to be addressed first, always, before you install a convertor, because they in all likelihood may be causing a false inefficiency code.  If the exhaust isn't the correct mixture or temperature to get the cat to light off, it won't light off!  That isn't the fault of the converter.

An aside - it is interesting that Chrysler has in big bold letters in their service information that a used front O2 and a new rear O2 can and will throw a catalyst inefficiency fault.  (A lazy front O2 and a quick rear O2 looks a lot like a bad cat) And the fix is... never replace the rear O2 by itself.

Converters can die.  Porsche converters separate from the steel shell causing them to fail and give a CEL.  I’m sure it’s age and vibration that cause it and poor bonding.  There is nothing wrong with replacing bad converters.  

whiskey_business:

Thanks, I appreciate the info. The engine seems to run okay-ish when stone cold, but as it warms up, while still cold, it gets worse. It does misfire under WOT, in fact in the 1000-2000rpm range at WOT it is probably the worst for the particularly problematic cylinder. For the other cylinders, they're a little worse under WOT, but not a lot. Low load seems to be the worst for the other cylinders, idle, throttle lift off, gentle acceleration.

Regarding the VVT and camshaft position sensor as possible causes - would an issue with those suggest misfires occurring the same time with all cylinders? The issue is weird, it occurs kind of randomly from cylinder to cylinder. There are definitely times when more cylinders are exhibiting the problem and to greater degrees. Often when a cylinder starts misfiring it will be more likely to do so for the next little bit. Often 2 or 3 will misfire. Sometimes it is all of them, to varying degrees.

Part of me is not sure what to do with the suggestions. I'm sure it's theoretically possible to fix my vehicle, but it's likely not possible for it to be fixed under the current system utilized by the dealership/GM. There's only like 4-5 non-core components that seem likely to be possible causes for this type of issue. If I was working on it myself and couldn't make any definitive determination, as a worst case scenario I could buy a part, try it out, if it didn't fix the problem, sell it and try swapping another possible part. Their system is very limiting and certainly doesn't allow for experimentation like that. They'd prefer to return a broken vehicle, return a bunch of times and have the customer without a vehicle for a protracted period.

Regarding the cat - My RX-8 went through 2. When the first one failed it definitely introduced a light hesitation under acceleration. The current hesitation is really bad due to the one bad cylinder. Prior to the fuel injector replacement it was gentler, so I wouldn't completely rule it out as a contributing cause. Obviously when the spark plugs fire the exhaust valve is closed, so there isn't a direct involvement, but it could be impacting what the car thinks is going on...  It makes sense to me that the cat would clog up, even without melting, etc.. A catalyst is a chemical that causes other chemicals to go through chemical change when exposed to the catalyst. If that chemical is covered with soot, etc. from incomplete combustion, etc. I can't see how it could do it's job. It also makes sense that the car can't tell if the cat is working correctly when there are general poor running conditions.

The AFM (active fuel management aka. cylinder deactivation) was mentioned earlier - Manual transmission Camaro's don't have it, only the autos.

I was talking to GM customer care again. They're about as useful as writing yourself a note on a peirce of paper and then lighting it on fire.

In reply to Snrub :

If a converter was clogging up, you would see it as negative fuel trims on that bank and positive fuel trims on the other bank, since there is only one MAF to measure the engine's airflow and the non-clogged side will be getting a majority of the air.

However, if there are significant misfires, the converter isn't going to be functioning properly, so it will set a catalyst inefficiency code even if it was in perfect condition.  Generally, for this reason, the computer will not bother looking at the cat if there are active misfires, but it is entirely possible that the threshold of misfires that you are experiencing isn't high enough to do this and/or they don't have a long enough timer after it stops misfiring.  (It's a new engine design, new everything, and these things are rarely perfect out of the box.  That's why one of the steps for weird issues is to make sure it has the latest flash - improvements get continually made)

Misfiring needs to be addressed first and foremost.

Uh... how much longer is the lease?  Why don't you drive it like you stole it until then and give it back to GM and be done with it?  Not your problemo anymore, eh?

I think it needs an Italian tune up.

The lease has ~2.5 years left to go.

Today I found out:

Apparently the misfire in the really bad cylinder was caused by a bad spark plug wire. The issue began after 2 visits ago when they changed the spark plugs, so I suspect it was damaged as a result of repeatedly changing spark plugs (ie. man handled). We now know they can fix a failed spark plug wire, but it takes multiple visits and 2 weeks to do it. :)

They're replacing the one cat and the O2 sensors on both sides of it, but they still haven't arrived. They don't seem to acknowledge the misfires, but they do acknowledge the car is running too rich and they're trying to fix that. They have said they need to replace the cat and O2 sensors before they can diagnose the rich condition issues. I suspect it's all correlated, so I'll let them do what they're doing, even if it's not my preferred method.

Knurled - what you've said makes sense to me.

They're giving me a rental today and no, the model they've reserved is not interesting.

Sounds like your on the right path anyway!

I wonder if correcting the spark issue and resetting the computer will let things re learn themselves. 

I happened across this  on IATN this morning.  No idea if it has any bearing on your situation.

2014 Chevrolet Camaro LS 3.6L Cuts out

I have a similar vehicle. I can compare data recordings. switch sensors etc. This vehicle acts like it was running out of gas high, pressure fuel is 1200+ Spark plugs are fouled, short and long term trims near 20, 02 readings drop to near o. Cold it runs about long enough to go closed loop. Restart,10 seconds. let it cool it will run longer. My Cadillac upstream o2 volts never drop below .9 and are stable on the scanner graph. The Camaros fall all the way to zero after a few spikes. The plugs are black ( not lean). I have GDS 2 and a scope, the crank and cams all have clean signal and are synced.

Updated on Jan 10, 2019 7:52 PM

The exciting conclusion...kind of. By unplugging the high pressure fuel sensor the car runs, it?s in limp mode but you could drive it. My car running at 590 psi why was Camaro desired 1400 and computer reading 1500? $40 for the sensor I will replace it and see, if not I will look further into the solenoid and high pressure pump. I am thinking the sensor is a typical 5000psi linear transducer. .5v = 0PSI and 4.5v = 5000 psi. I will check it tomorrow.

FIX posted on Jan 11, 2019 8:13:04 PM

There were 13 codes and they all were misleading. I was fortunate to have a similar car as I was able to scope both vehicles and ignore the codes pointing to timing. In the data comparison the answer was right there. My car was running on 590psi fuel pressure. The Camaro was 1200+ but so was the desired pressure. Unplugging the high pressure fuel sensor under the plenum made it run in limp mode, replacing the sensor fixed it. Now the Camaro was idling at 580psi. Look for that high pressure fuel reading. This vehicle also needed the fouled spark plugs replaced to eliminate all misfires.

Computer Codes & Descriptions

P0016- Crank Cam not plausable
P0017- Crank Cam not plausable
P0018- Crank Cam not plausable
P0019- Crank Cam not plausable
P0097- Intake air temp sensor 2 low voltage
P00f4- Intake air humidity low voltage
 

Other Test Results

scope crank and cams - all synced to known good
switched maf, map - no change

In reply to Streetwiseguy :

Wow!

Streetwiseguy - Thanks for the info.

I'm not sure what I can do to influence the troubleshooting at this point. The dealer has had the car for just shy of three weeks and there is no end in sight. They replaced a cat and O2 sensors, drove it for a while, CEL came on for the other cat, they replaced it too. They drove it further and they acknowledge a misfire on a different cylinder, but the CEL hasn't come on yet. They've reached out the GM TAC again. Apparently they need some kind of approval to continue. I'm glad they haven't simply sent the car back to me broken and that they're finding obvious problems themselves without me having to plead with them.

In reply to Snrub :

At least it sounds like they're finally determined to figure out what's going on and fix it instead of just giving it back and waiting for you to say "guys, it's still broken"

In reply to Snrub :

How long do they have to have the car by Canadian law before you can skip a payment or walk away from the lease entirely?

In reply to Snrub :

At least they are FINALLY working on actually trying to fix the problem. Hopefully you end up with a new engine ASAP. Good luck!

Javelin said:

In reply to Snrub :

How long do they have to have the car by Canadian law before you can skip a payment or walk away from the lease entirely?

To skip a payment, I don't know. Technically the rental is of similar monetary value... For walking away, which I wold love to do at this point, there's not a clear line. The CAMVAP process created by the industry is a binding arbitration process. You have to present your case to an arbitrator and convince them. Apparently most of the time they simply order more warranty repairs. It's possible to sue as well, but that would take a long time and cost a bunch. It's not clear to me what makes a "strong" legal case.

Dave M - I'd certainly like a new engine. My concern is, would a new short block fix the problem? I doubt it would, they'd re-attach the same parts back on it that have been causing the issue.