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

In reply to Snrub :

I respect your position. 

But you bought a warranted car, then asked a dealer to fix it. If you really only trust yourself to watch out for you, you are certainly welcome to fix it yourself. 

Maybe you are not exactly the “warranty kind of owner”. 

But your opportunity is this. You OWN a car that someone else is responsible to repair.  All you have to do is follow their rules. One of those rules is that you don’t play with it. 

You can use the warranty you paid for, or choose not to. 

I have to agree with the hive on this issue, call GM.  I had an experience with the wife's 2013 Acadia info-tainment system freezing up.  After the dealer couldn't fix it the first time I posted on an Acadia forum and that day GM customer service reached out.  The GM rep set us up with another appointment, insured there was a loaner car and kept in touch with the dealer directly to make sure we were taken care of.  After it was fixed they sent me a $300 gift card for dealer accessories.  Though it was frustrating in the beginning, once GM was involved it was resolved with no input from me.  

NickD - that's good info to hear, thanks.

As far as I know the dealer drained some gas, changed some plugs, filled up some gas, did some analysis related to the fuel injectors and returned a broken car to me twice.

As mentioned earlier, yes there is another dealer I can go to. I will be calling another dealer or GM today.

I'm not a warranty kind of person. I hate taking the car to people who's interests have narrow overlap with actually fixing my car. That said, I picked up a newer car in part because I was getting tired of all of the effort I was putting into the last one.

OP asked how many misfires are "acceptable", the answer is zero on a new car with 13,000 miles.  The only misfires I've had with "modern" cars were related to bad coil packs.  Replace them, and the plugs, you're back to new.  The dealer is full of E36 M3, find a new one and call GM.

A coworker also bought a new Acadia last spring, before they drove off the lot the stereo went to 11 and they couldn't turn it down.  It spent 6 months at the dealer before GM said stop berkeleying around and give them their money back or a new car.

Come to think of it, the last car I had with a misfire was my 87 Golf and that was due to a bad plug wire. 

Zero misfires are acceptable.

This dealer experience is unacceptable. The entire point of having a car with a warranty is so that if something goes wrong, you can drop it off, take their loaner/drink their coffee, and not bother with it yourself. Find a new dealer and/or reach out to GM corporate. I dealt with a few lousy Ford dealers before finding one I deemed worthy of working on my truck, even for oil changes. Unfortunately, not all service departments are the same.

I booked an appointment with another dealer.

The service manager at the dealer refused to answer most of the questions I had about the failure to fix the issue, the illogic and contradictions in their story,  the lack of accountability, the failure of their decisions based on the diagnosis they claim, etc. They want me to continue driving the vehicle in it's current misfiring state. I asked for a commitment on how much gas I need to run before the "bad gas" diagnosis no longer applies to the continued presence of the original symptoms. Crickets.

I tend to think zero misfires is acceptable as well. If anyone would like to log/post misfire data (even just a description of the results) from a current gen LT1 or even a LSx, I would be very grateful.

Good luck! I am in the zero misfires is acceptable camp too.

Don't have any LT1s on hand to hook an MDI up to right now, but, yes, zero with maybe 1 or 2 every once in a great while is what it should be. I know that the LT1, at least in the C7s, tends to feel like it has a slight misfire at idle, although it's nothing that sets a CEL or even shows up in the misfire tracker in GDS2. Not sure what that's about.

That's awesome feedback guys, thanks. It's nice to know I'm not crazy about the misfires.

The below info isn't meant to apply to the OP car.  They obviously have a problem, and I am in the "injector as possible cause" camp.

If you are watching on a scan tool, an engine with no issues can show misfires during its continuous monitor.   Depending on if you are looking at the OEM or Generic OBD2 data you may see different misfire counts on the same car.   I have seen 20-50 on some cars before it resets.  What is acceptable will vary by vehicle and engine management system (Bosch/Conti/Delphi/etc).  It is also not unusual to see induced misfires at cold start.  I have never seen published numbers from any OEM showing how many are ok.  You have to compare to a "known good" to figure it out. As long as it is below the DTC set parameters if wont turn on the MIL or store a code.  Misfires on the counter is not always indicative of a problem.  

Again, not talking about the OPs car, that is broken and has a problem.  I am talking in general.

NickD said:

Don't have any LT1s on hand to hook an MDI up to right now, but, yes, zero with maybe 1 or 2 every once in a great while is what it should be. I know that the LT1, at least in the C7s, tends to feel like it has a slight misfire at idle, although it's nothing that sets a CEL or even shows up in the misfire tracker in GDS2. Not sure what that's about.

GM has a strategy where they will induce a deliberate misfire at idle and on cold starts, to light off the cat faster/keep it lit.  This will not show up under misfire counts.

I have only seen it on Ecotecs but I would not doubt that they might do something similar on a V8.

dean1484 said:

How does data logging misfires void the warranty.  Again a bunch of bs. 

I am not saying it will, but I am saying that having random E36 M3 plugged into the DLC is one of the first things you look for when diagnosing a drivability problem.  Especially one that only acts up for the vehicle's owner.

Sometimes third party stuff is so poorly engineered that it does some really unexpected things.  Usually it is mundane network errors, things staying powered up after you shut the car off, etc.  It is not mucn pf a stretch to suggest that further errors may be introduced, and it would be a nice slimy go-berk-off sendoff.

Knurled. said:

dean1484 said:

How does data logging misfires void the warranty.  Again a bunch of bs. 

 

I am not saying it will, but I am saying that having random E36 M3 plugged into the DLC is one of the first things you look for when diagnosing a drivability problem.  Especially one that only acts up for the vehicle's owner.

 

Sometimes third party stuff is so poorly engineered that it does some really unexpected things.  Usually it is mundane network errors, things staying powered up after you shut the car off, etc.  It is not mucn pf a stretch to suggest that further errors may be introduced, and it would be a nice slimy go-berk-off sendoff.

I get that we're discussing theoretically here, but given that the port is required by law to be available for diagnostics and car companies know there are widespread use cases such as insurance monitoring, it would behoove them to design the OBDII port to be as tolerant as possible and to isolate it from the systems affecting the rest of the car. Unless there is a legal reason that prevents this kind of isolation, worse case scenario a bad OBDII monitor might be able to break the system related to the port, but it should not affect the rest of the car.

In my case I just want to clarify that my issue was present with and without the OBDII dongle plugged in. I only started monitoring/logging after the dealership gave an incorrect diagnosis. I only presented collected data to them after two failed attempts to fix the issue.

I don't disagree that a slimy person might attempt to use this to say "not our problem." I'm dealing with people who are standing their ground in the face of overwhelming evidence to the contrary.

Snrub said:

I get that we're discussing theoretically here, but given that the port is required by law to be available for diagnostics and car companies know there are widespread use cases such as insurance monitoring, it would behoove them to design the OBDII port to be as tolerant as possible and to isolate it from the systems affecting the rest of the car. Unless there is a legal reason that prevents this kind of isolation, worse case scenario a bad OBDII monitor might be able to break the system related to the port, but it should not affect the rest of the car.

The nature of the standardized datalink connector is that all major networks on the car will "break out" to the connector.  If you have comms issues, you can access the network in question directly via the DLC and observe what is going on with a 2-channel scope.  And if the network is dead, there are other basic standardizations involved so you can check to see where the break in the network is.

Somehow, incidentally, Chrysler has its high speed CAN divorced from the DLC.  All data passes through a different module before it can get to the DLC.  Makes diagnostics "fun" sometimes and you usually have to modify the wiring harness so you can talk to the network directly.

Corollary to this, any scantool or other device plugged into the DLC will BECOME a device on the network.  This is by design.  All those little dongles are doing (or SHOULD be doing) is observing the data that is being transmitted on the network.  But because you can command the modules to do things, they will happily accept commands from devices plugged into the DLC.  (Which is where thieves love keyless ignition)  And likewise, anything made since 2004 or so must be reflashable by generic tools, so it is in the realm of possibility, if multiple weird things happen, for a module to get scribbled over.  Maybe.  It would be a hell of a long shot.

But usually, they just confuse networks they shouldn't even be talking to and, say, your battery keeps dying because the rear amplifier is never getting its "shut down" signal on the entertainment bus...

They don't want to see your data, really.  They can't use it for warranty claims and the service manager probably doesn't even know what you're showing him.  Find a better dealer.  I'm still saying injector leaking issue.  

eebasist - I inteded to commented earlier; Thanks for the suggestions. I don't think it matches any of those situations exactly.

Knurled - Interesting info, good to know. That's really not an intelligent design. Perhaps it's a function of the 1992 legacy (that's when it was the spec was "approved") and I'm guessing it was designed at least several years before that. It could function exactly the same while be isolated by an module that does the listening and merely passes along data. For the "write" functions, it should be a complicated enough signal that it can't occur accidentally. Who knew Chrysler had so much common sense. :)

Underpowered - I agree the service manager's response suggests he had no idea what I was showing him. I'm sure that contributes to the low value he placed on the data. I have an appointment at another dealer.

Reminds me of what I went through with my mustang in highschool. I didn't have a warranty, but...   would have a random no-start issue. Sometimes it would just decide it didn't want to fire. Just crank and crank. Wait a few days, starts fine.  So it goes to a dealer. They seize upon the aftermarket alarm a PO had installed, call in a specialist to remove it and return the car. Not fixed. Then fuel pump, not fixed. Then coils. Not fixed. I'm getting pissed. Go to different dealer. They replace a $0.02 wiring connector. Fixed. I had a lot of fun going after dealer one for how much of my money was wasted, got half back after a lot of effort.

Snrub said:It could function exactly the same while be isolated by an module that does the listening and merely passes along data.

That would also be completely useless.  I don't just want to see data, I need to be able to control things directly if I want to properly diagnose a problem.  For example, let's say it's a Saturn with an EGR position failure.  I plug in the scantool and use it to command the EGR to open while watching the EGR position PID.  It doesn't change, so I backprobe the EGR valve and watch it on a scope while commanding change with my scantool.  I don't see the line ever getting pulled to ground, so I know the PCM is faulty because it blew a driver transistor.  (Technically I should also be verifying the wiring, but in theory the wiring is good because it's not setting a circuit fault)  If you just read the code, or even remove the EGR valve and watch the pintle, you would assume that the valve is bad.  That isn't diagnosing a problem, that is throwing parts at it and crossing your fingers.

This is why code readers or generic data scanners like Torque are generally consumer-grade toys and not something really useful.  They're hand drills vs. vertical mills.

I’d go to dealer #2 and tell them NOTHING except the following:

“My new car with 13,000 miles isn’t running smoothly. It showed a CEL so I took it to Chevy dealership service dept X. They checked it out and suspected bad gas. (I had filled it at ZZ like I always do). X says they emptied the tank and refilled with “good gas”, but car still isn’t running smoothly. If one tank of bad gas was the problem, it seems like fresh gas should correct it. But it didn’t - so I decided to try a different service department.

Will you please check it out for me?”

RFor whatever it’s worth, I had a similar issue on my E90 BMW 335. When temps dropped below freezing, the car would refuse to start. When it finally got going, it was running rich and misfiring. 

Turns out there was a (known) problem with “leaky injectors” that was exacerbated by cold temps. Even though only two were bad, we replaced all six. A short time later, I had to also replace the coils and plugs. Has been running smoothly ever since. 

Years ago I was shop foreman at a GM dealer.

if we ran into a problem that we couldn't solve we called the GM hot line.   99% of the time they had the fix.

I guess todays people just won't take the time or even care.

iceracer said:

Years ago I was shop foreman at a GM dealer.

if we ran into a problem that we couldn't solve we called the GM hot line.   99% of the time they had the fix.

I guess todays people just won't take the time or even care.

The nice thing about the tech line was that, not only could you (theoretically, anyway) bend the ears of the people who engineered the system you were trying to solve, they were a national hotline.  There's a good chance that someone else in the country has run into the weird issue you are having and they can direct you where to look.

As a practical matter, calling the hotline was discouraged when I was at a dealership.  Waste of time, just throw parts at it and see if that fixes it.

 Bought a backhoe with a starting issue once. Had it four years. Into the dealership around 30 times and finally sold it with the same issue. 

OHSCrifle said:

I’d go to dealer #2 and tell them NOTHING except the following:

“My new car with 13,000 miles isn’t running smoothly. It showed a CEL so I took it to Chevy dealership service dept X. They checked it out and suspected bad gas. (I had filled it at ZZ like I always do). X says they emptied the tank and refilled with “good gas”, but car still isn’t running smoothly. If one tank of bad gas was the problem, it seems like fresh gas should correct it. But it didn’t - so I decided to try a different service department.

Will you please check it out for me?”

I agree that I shouldn't say too much or it could taint their opinion of the situation. I tend to think even the very mention of "bad gas" could do the same and put blinders on the investigation. My plan is that if they suggest "bad gas" I'll explain why it is not, but otherwise, I don't want to them chasing demonstrably non-existant zebras, instead of trying to find the horse.

Knurled - I absolutely get your point and it's clear you know a lot more about this topic than I do. Sounds like you're right based on what OBDII is now. I still think in an ideal world some kind of buffer interface would be the way to go. The buffer interface could require a signal (or better yet, transmit actual code) that could cause accidental commands/interferences that could not be produced by poor electronics. The buffer interface could theoretically allow for access/detection of literally everything that's detectable behind it. For proprietary sub-systems, there could be a template of specs to be monitored by the buffer interface, or custom scripts per application to gather the data. The more I think about this, it really might require an OBDIII spec.

LanEvo - A lot of people seems to be suggesting fuel delivery. Your comments do not sound dissimilar to my issue.

It's interesting to learn how many current former GM tech's we have on this forum. :)

In reply to Snrub :

Probably is a good idea not mentioning gas at all.