*HELP*Misfire Codes Continue to Occur

[MrChrisLS3]

Originally Posted by tuki3388

I have ran cleaner through my tanks and every winter I put seafoam or another cleaner additive in and this still occurs.

On the Direct Injection engine, using anything in the fuel tank isn't going to do much to anything other than the injector itself. Google Direct injection+valves or carbon. You'll get a pretty clear picture of what's going on here.

I think you posted that you have around 44K miles. If that's the case, you might be beyond the chemical top end clean. The trouble with DI that hasn't been solved yet is that there is no gas sprayed on the back of the valve to "clean" them. So, the oil residue from the PCV builds up and bakes on the valves and valve stems. This build up becomes rock hard, and chemicals, like Seafoam, or GM Top End Cleaner aren't going to do much. In fact, at this point, they more harm than good.

Once this carbon gets baked on, and builds up, it begins to flake off. There is only one place for these hard pieces of carbon to go, and that's in the cylinder. There, they can stick in the valve seat, not allowing the valve to close completely, thus losing compression. Furthermore, these pieces of carbon can work in between the cylinder walls and the rings, damaging both, again, loss of compression, blow by, and all that goes with that. The carbon pieces that do escape through the exhaust then get stuck to the catalytic converter, creating obvious issues there as well. Then there are smaller things, like the carbon clogging the injector port, getting stuck in the plug gap, things like that.

Unless a chemical top end clean is done as part of regular maintenance, say, every other, or every third oil change, depending on mileage and frequency, it really isn't effective. At this point, the only real solution is to take it in for a walnut blasting of the valves.

Is this your current problem? I have no way of knowing of course. However, think about this, if the dealer told you it was carbon build up on that cylinder, wouldn't it be a reasonable thought that the other five have the same issue? And if they did a chemical clean on it, chances are it didn't really so much actual "cleaning" at this point.

DI engines are great for producing power more efficiently, unfortunately, the PCV system on them has yet to be fully thought through.

[Flashpoint135]

Originally Posted by MrChrisLS3

On the Direct Injection engine, using anything in the fuel tank isn't going to do much to anything other than the injector itself. Google Direct injection+valves or carbon. You'll get a pretty clear picture of what's going on here.

I think you posted that you have around 44K miles. If that's the case, you might be beyond the chemical top end clean. The trouble with DI that hasn't been solved yet is that there is no gas sprayed on the back of the valve to "clean" them. So, the oil residue from the PCV builds up and bakes on the valves and valve stems. This build up becomes rock hard, and chemicals, like Seafoam, or GM Top End Cleaner aren't going to do much. In fact, at this point, they more harm than good.

Once this carbon gets baked on, and builds up, it begins to flake off. There is only one place for these hard pieces of carbon to go, and that's in the cylinder. There, they can stick in the valve seat, not allowing the valve to close completely, thus losing compression. Furthermore, these pieces of carbon can work in between the cylinder walls and the rings, damaging both, again, loss of compression, blow by, and all that goes with that. The carbon pieces that do escape through the exhaust then get stuck to the catalytic converter, creating obvious issues there as well. Then there are smaller things, like the carbon clogging the injector port, getting stuck in the plug gap, things like that.

Unless a chemical top end clean is done as part of regular maintenance, say, every other, or every third oil change, depending on mileage and frequency, it really isn't effective. At this point, the only real solution is to take it in for a walnut blasting of the valves.

Is this your current problem? I have no way of knowing of course. However, think about this, if the dealer told you it was carbon build up on that cylinder, wouldn't it be a reasonable thought that the other five have the same issue? And if they did a chemical clean on it, chances are it didn't really so much actual "cleaning" at this point.

DI engines are great for producing power more efficiently, unfortunately, the PCV system on them has yet to be fully thought through.

I agree with the above, what I don't understand is why none of this work is being covered under OP's warranty. I paid for nothing and all of it happened around 70k miles.

[MrChrisLS3]

Originally Posted by Flashpoint135

I agree with the above, what I don't understand is why none of this work is being covered under OP's warranty. I paid for nothing and all of it happened around 70k miles.

In his original post, he sad the dealer claimed the carbon build up as normal wear and tear, which is not covered under warranty. This a claim from the dealer that I, for one, would highly contest.

[tuki3388]

I appreciate your responses, I am reading them as I find time and will respond. Currently the dealership has had my car for 2 whole days and done nothing with it and wont return my phone calls.

[Ragnar]

Originally Posted by tuki3388

I appreciate your responses, I am reading them as I find time and will respond. Currently the dealership has had my car for 2 whole days and done nothing with it and wont return my phone calls.

[RACERJOE1]

If the plug, coil and plug wire have changed and it still randomly misfires I would suspect a problem in the wiring harness to the coils. Just a thought.

[tuki3388]

Originally Posted by MrChrisLS3

On the Direct Injection engine, using anything in the fuel tank isn't going to do much to anything other than the injector itself. Google Direct injection+valves or carbon. You'll get a pretty clear picture of what's going on here.

I think you posted that you have around 44K miles. If that's the case, you might be beyond the chemical top end clean. The trouble with DI that hasn't been solved yet is that there is no gas sprayed on the back of the valve to "clean" them. So, the oil residue from the PCV builds up and bakes on the valves and valve stems. This build up becomes rock hard, and chemicals, like Seafoam, or GM Top End Cleaner aren't going to do much. In fact, at this point, they more harm than good.

Once this carbon gets baked on, and builds up, it begins to flake off. There is only one place for these hard pieces of carbon to go, and that's in the cylinder. There, they can stick in the valve seat, not allowing the valve to close completely, thus losing compression. Furthermore, these pieces of carbon can work in between the cylinder walls and the rings, damaging both, again, loss of compression, blow by, and all that goes with that. The carbon pieces that do escape through the exhaust then get stuck to the catalytic converter, creating obvious issues there as well. Then there are smaller things, like the carbon clogging the injector port, getting stuck in the plug gap, things like that.

Unless a chemical top end clean is done as part of regular maintenance, say, every other, or every third oil change, depending on mileage and frequency, it really isn't effective. At this point, the only real solution is to take it in for a walnut blasting of the valves.

Is this your current problem? I have no way of knowing of course. However, think about this, if the dealer told you it was carbon build up on that cylinder, wouldn't it be a reasonable thought that the other five have the same issue? And if they did a chemical clean on it, chances are it didn't really so much actual "cleaning" at this point.

DI engines are great for producing power more efficiently, unfortunately, the PCV system on them has yet to be fully thought through.

I could not agree more, I'll look more into the walnut blasting to see if its an option I can afford. My issue is the service records of recent events are in the glove box in my car while the older records are at home filed away. What scares me is if this needs to be done every four oil changes or so and this dealership is charging 300$ I won't be able to afford it.

[tuki3388]

Originally Posted by Flashpoint135

I agree with the above, what I don't understand is why none of this work is being covered under OP's warranty. I paid for nothing and all of it happened around 70k miles.

They told me it was not covered under any warranty because GM said "it is normal wear and tear" and I was on my own. My car is not covered under basic but I purchased the GM PP warrant and are still covered under power train till the end of the year. If there is a way you could show me the dealer you took it too covered it under warranty I would appreciate.

[tuki3388]

Originally Posted by MrChrisLS3

Try a different dealership. Maybe even a Cadillac dealership, they have experience with these engines. Point is some service dept are better than others.

A 300 code is misfire code, but how did they determine cyl 3? I had a coil pack go out on my old pre di caddy, and was a 303 code, meaning misfire cyl 3.

I won't take it to the Cadillac dealer in town. I had an issue with the Chevy dealer and they didn't put my oil filter on correct and had my car towed back. Went to the Caddy dealer to try and get a wheel replaced under insurace and they screwed me around for a month. Finally I went to the dodge dealer and they got me done in under a week. (apparently I have bad luck with car dealerships while at college)

[MrChrisLS3]

Originally Posted by tuki3388

I could not agree more, I'll look more into the walnut blasting to see if its an option I can afford. My issue is the service records of recent events are in the glove box in my car while the older records are at home filed away. What scares me is if this needs to be done every four oil changes or so and this dealership is charging 300$ I won't be able to afford it.

Well, if done every third or even fourth oil changes, based on 5000 miles, we're looking at $300/year, that's about $25 a month. However, at this point, as I said, it could do more harm than good until you get the blasting done. Not to mention that this is a really simple procedure that you could do yourself.

On the other hand, carbon build up may not even be the issue here. It very well could be electronic, a bad injector, harness issue. GM has field service manuals for every product they sell. In there, are trouble shooting protocols, if the tech follows this, the problem will typically be found. At this point, they are probably just moving down the list. The good news is that if they have already done the 'wear and tear' portion, the rest of the list is probably going to be warranty stuff, let's hope.

[tuki3388]

Originally Posted by MrChrisLS3

Well, if done every third or even fourth oil changes, based on 5000 miles, we're looking at $300/year, that's about $25 a month. However, at this point, as I said, it could do more harm than good until you get the blasting done. Not to mention that this is a really simple procedure that you could do yourself.

On the other hand, carbon build up may not even be the issue here. It very well could be electronic, a bad injector, harness issue. GM has field service manuals for every product they sell. In there, are trouble shooting protocols, if the tech follows this, the problem will typically be found. At this point, they are probably just moving down the list. The good news is that if they have already done the 'wear and tear' portion, the rest of the list is probably going to be warranty stuff, let's hope.

True, I do hope you are right and that the rest will be under warranty for the remainder of the problem. 300$ a year to prevent this issue does not seem like a lot, it will seem smaller once i'm out of school. I just want my car back and in working order.

[tuki3388]

To anyone who is still following this thread, the dealership has had my car now for 6 days and have only re-checked the code. I have called GM and gotten them involved. Time to see what happens.

[wjmeyer]

6 days, who is working service at that dealer, Moe, Larry & Curly?

[Elite Engineering]

I did not see in the thread that the timing chains and related components were changed. This can cause the code and misfires from stretch, but I would first remove the PCV barb from the rear of the passenger side valve cover and inspect and perform the drill mod:





This was not corrected until the aluminum valve cover equipped LFX engine in 2014 (some late 2013 as well).


Remove, drill top hole to 1/8" and bottom 2 to 5/64: each. Clean and re seat in the valve cover. When these clog, no dirty/foul side evacuation takes place and thus oil is ingested upstream of the throttle body causing misfires as well as other related issues.


Let us know if we can be of more help!