Dealer not honoring warranty work..2018 5.3 Yukon issues

[smokey_mountain]

I am in NC, RPM Motorsports in Garner NC are well respected by the GM Corvette and other GM vehicle performance crowd. I took it to them and they found 4 injectors in bank #2 to be out of spec, but I asked them to stop diagnosing as it was on my dime. Entire bank of injectors is most likely not defective but rather there could be issues with vacuum on bank #2 or with running too rich and O2 sensors. Folks here are telling me that injectors cannot be failing without a code due to strict emission controls in the truck but RPM Motorsports guys found bank #2 to be 30+% out of spec on the injector balance test and zero codes... How is that possible, I do not know but I posted RPM results here, they are confident on their findings. RPM told me that to really find out what is wrong one needs to do leak down test, etc. I was already $300+ in rental and mechanics fees, I stopped in hope that diagnostics from RPM will be enough from GM dealer to fix but no dice... no codes, no issues per the GM.

Hey Dmitry, where do you live? Why not get with someone more knowledgeable about autos and have them check it out with you? Live in Florida by chance?

 

[swathdiver]

I am in NC, RPM Motorsports in Garner NC are well respected by the GM Corvette and other GM vehicle performance crowd. I took it to them and they found 4 injectors in bank #2 to be out of spec, but I asked them to stop diagnosing as it was on my dime. Entire bank of injectors is most likely not defective but rather there could be issues with vacuum on bank #2 or with running too rich and O2 sensors. Folks here are telling me that injectors cannot be failing without a code due to strict emission controls in the truck but RPM Motorsports guys found bank #2 to be 30+% out of spec on the injector balance test and zero codes... How is that possible, I do not know but I posted RPM results here, they are confident on their findings. RPM told me that to really find out what is wrong one needs to do leak down test, etc. I was already $300+ in rental and mechanics fees, I stopped in hope that diagnostics from RPM will be enough from GM dealer to fix but no dice... no codes, no issues per the GM.

Ok. What the GM Tech wondered was if the test on Bank 2 was run at the same temp as Bank 1. If one was run first on a cold motor and then the other once up to temp, they will certainly be different and there is nothing wrong with that. If they did that and are humble folks, they will admit such an error.

Why don't you get one of those Bluetooth OBDII adapters from Amazon and download the Torque Pro app for your phone. Then you can monitor engine functions yourself and look for trouble, like Fuel Trims and injector pulsing. Post data here or at Performance Trucks and you'll know pretty quick what might be amiss.

 

[smokey_mountain]

Truth is that RPM Motorsports's is a GM performance shop and the tech who diagnosed the problem is 15+ GM tech at the dealership as master tech, they are readily available to answer any questions, I gave all info to Hendrick GMC and provided all the phones. RPM Motorsports did warm up the truck before they measured to 140 degrees, he has all data from that GM-approved machine that he used to measure injector balance.

Thank you @swathdiver I do have OBD adapter and I ran OBD Fusion on iPhone for a day. I do not see a place in that app to see Fuel Trims and injector pulsing data there. I think Torque Pro is next app to buy. I will run it today.
here is a video from OBD Fusion

Ok. What the GM Tech wondered was if the test on Bank 2 was run at the same temp as Bank 1. If one was run first on a cold motor and then the other once up to temp, they will certainly be different and there is nothing wrong with that. If they did that and are humble folks, they will admit such an error.

Why don't you get one of those Bluetooth OBDII adapters from Amazon and download the Torque Pro app for your phone. Then you can monitor engine functions yourself and look for trouble, like Fuel Trims and injector pulsing. Post data here or at Performance Trucks and you'll know pretty quick what might be amiss.

 

[Bob2C]

I have OBD fusion and just realized user defined PID’s can be imported into the app. Now I’m going to run it

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[smokey_mountain]

You are a hero @Bob2C ! I will do that too!

I have OBD fusion and just realized user defined PID’s can be imported into the app. Now I’m going to run it

Sent from my iPhone using Tapatalk

 

[Bob2C]

You are a hero @Bob2C ! I will do that too!

Go to settings, user defined PID, then click menu on upper right then select import built in PID

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[smokey_mountain]

Yes imported them, thank you, @Bob2C

 

[smokey_mountain]

I have tried custom PIDs for GM for injector balance but I am getting all values as zero, OBD Fusion does not see these custom user PIDs, suspect I am doing something wrong. However logs are created now and attached.
https://drive.google.com/file/d/1T2FGS2bybzxairxZbO6_MZ8lB2cnd6ni/view?usp=sharing

View attachment 234257

In the monitor section of OBD Fusion I see misfires, it changes but I have seen as high as 6 misfires in 7 minute ride, on #7 and 1-2 on other. I suspect it is totally normal but I do not know how to interpret.



@swathdiver calling on your expertise if possible.
@Bob2C do you see user-defined PIDs value in your OBD Fusion?

 

[Bob2C]

I have tried custom PIDs for GM for injector balance but I am getting all values as zero, OBD Fusion does not see these custom user PIDs, suspect I am doing something wrong. However logs are created now and attached.
https://drive.google.com/file/d/1T2FGS2bybzxairxZbO6_MZ8lB2cnd6ni/view?usp=sharing

In the monitor section of OBD Fusion I see misfires, it changes but I have seen as high as 6 misfires in 7 minute ride, on #7 and 1-2 on other. I suspect it is totally normal but I do not know how to interpret.

https://drive.google.com/file/d/1_23Yz1DBvs5sjhxIRhimFJXSP2F8WpzC/view?usp=sharing

@swathdiver calling on your expertise if possible.
@Bob2C do you see user-defined PIDs value in your OBD Fusion?

I have not had a chance to run the software. I got caught up in trying to find a coolant leak in my other car. I will try to run it tomorrow.


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[smokey_mountain]

This is what I am seeing on another 7 min ride, looks like Bank 2 is not doing well Cyl #7 is consistently showing misfires

 

[Bob2C]

This is what I am seeing on another 7 min ride, looks like Bank 2 is not doing well Cyl #7 is consistently showing misfires

View attachment 234291

I had a few misfires on 3,5,7. 7 being the most but not as much as you. I pulled a full report. Trying to figure out how to get it to you. It’s an html file.

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[Doubeleive]

I would check for a intake leak, nobody will probably agree with me but I have seen it before, you can do it with a can of starting fluid along the edges of the intake and see if the idle changes won't cost you anything but a couple dollars for a can of starting fluid. Better to do it first thing in the morning while everything is cold.

 

[smokey_mountain]

I would do that. My problem is that I cannot prove anything to the dealer to fix it. Misfires are recorded in OBD monitors on the same bank of cylinders that independent engine mechanic measured injectors being out of spec. There are still no trouble codes anywhere in the system on that. I suspect 11-15 misfires is not enough to trigger any DTCs. The fallacy of this situation that GM and dealer won't admit that there is a rough idle problem until there is code recorded even then there is no guarantee that they would accept it. At this point I am not sure what I need to do, if I show this misfires to the dealer, they will say "within spec", "incorrectly measured", "consumer OBD scanners are not acceptable", "you (me in this case) are an idiot and do not know how to interpret misfires", "no codes - no problem", etc.

I would check for a intake leak, nobody will probably agree with me but I have seen it before, you can do it with a can of starting fluid along the edges of the intake and see if the idle changes won't cost you anything but a couple dollars for a can of starting fluid. Better to do it first thing in the morning while everything is cold.

 

[calif phil]

You could induce a vacuum leak or pull off a couple of plug wires to log a DTC. Then maybe they would take a better look.

 

[91RS]

Cylinder 7 is bank 1 not bank 2.

 

[smokey_mountain]

I stay corrected then. Misfires on the odd cylinders but out of spec measured even cylinders. Now, there is no logic in my finding at all then - bottomline: truck is still rough idling and now even in P both cold and warm.

Cylinder 7 is bank 1 not bank 2.

 

[Doubeleive]

I would do that. My problem is that I cannot prove anything to the dealer to fix it. Misfires are recorded in OBD monitors on the same bank of cylinders that independent engine mechanic measured injectors being out of spec. There are still no trouble codes anywhere in the system on that. I suspect 11-15 misfires is not enough to trigger any DTCs. The fallacy of this situation that GM and dealer won't admit that there is a rough idle problem until there is code recorded even then there is no guarantee that they would accept it. At this point I am not sure what I need to do, if I show this misfires to the dealer, they will say "within spec", "incorrectly measured", "consumer OBD scanners are not acceptable", "you (me in this case) are an idiot and do not know how to interpret misfires", "no codes - no problem", etc.

i figured the point was to find the problem, regardless of who pays for it to be fixed in the long run. just offering a suggestion of what the problem could be.

 

[swathdiver]

Right, maybe it's the other bank with the problem since that is where the misfires are. Look, I have the older generation engine so it's not the same as yours. I have NEVER recorded a misfire on any cylinder with my Tech-2 running for hours at a time while we drive around. That being said, I would imagine that the engineers have a number that is not acceptable somewhere you have to find it. I'm still having trouble with my eyes but will look through my shop manuals for the GEN IV engines and report back if I can find where the information resides.

This is all good though, you know have another piece to the puzzle.

 

[swathdiver]

Ok, not finding a specific threshold before codes are thrown. However, the manuals do describe your exact conditions and suggest checking the fuel for contamination and the plugs and wires. If this were my truck, I'd run only Top-Tier high octane gasoline in it, then put dielectric grease on all spark plug ends which also makes sure they are all properly seated. I would also verify the gap on the spark plugs. Another thing mentioned in the book, was to make sure the injector harness was plugged into the right cylinders (no brainer right?) and misfires on 1 and 7 (2 and 6) could be an impending sign of an AFM problem coming up. Hope this helps Dmitry.

 

[smokey_mountain]

Thank you, I spoke to RPM Motorsports briefly just now, and their answer is that it does not sound right, 11 misfires in <7 minutes, does not sound right. Of course phone diagnostics is not effective they only go by what I describe and what I see on OBD. What puzzles them as well how the threshold is set that I do not get DTCs.

Right, maybe it's the other bank with the problem since that is where the misfires are. Look, I have the older generation engine so it's not the same as yours. I have NEVER recorded a misfire on any cylinder with my Tech-2 running for hours at a time while we drive around. That being said, I would imagine that the engineers have a number that is not acceptable somewhere you have to find it. I'm still having trouble with my eyes but will look through my shop manuals for the GEN IV engines and report back if I can find where the information resides.

This is all good though, you know have another piece to the puzzle.