Dealer not honoring warranty work..2018 5.3 Yukon issues

[91RS]

I don’t know if I missed it or don’t remember but is this a 5.3L or 6.2L? What fuel grade are you using?

 

[smokey_mountain]

5.3L 6-speed. Exxon Mobil 1 Regular. Two dealers told me explicitly not to use Premium with 2018 5.3L engines. Hendrick and Thompson GMC both told me that. Top Tier but not Premium.

I don’t know if I missed it or don’t remember but is this a 5.3L or 6.2L? What fuel grade are you using?

 

[91RS]

It shouldn’t be needed with the 5.3L but it isn’t going to hurt anything. Run it down to empty and fill up with premium and see what happens.

 

[swathdiver]

It shouldn’t be needed with the 5.3L but it isn’t going to hurt anything. Run it down to empty and fill up with premium and see what happens.

I think he's on his first or second tank of premium.

 

[smokey_mountain]

I did 1 full tank of Premium and will try another tank of Exxon Premium on the way to/from VA this weekend. I will drive "hard". I will convince my wife to take the truck to the Blue Ridge Highway if it is not closed for winter, that will give valves some serious workout.

 

[smokey_mountain]

Here is the summary of everything that Medlin GMC checked. Hard to fault this dealer, they really tried based on this work order? What do you guys think?

 

[smokey_mountain]

I may need to ask for wisdom again...
I am reading that misfires in $06 monitor misfires should be zero. I only have OBD Fusion to read $06 but what is the tool that dealer would accept as evidence of misfires? What shall I buy to log misfires to present to the dealer? I posted above their results, they said zero misfires anywhere during dealer’s testing. I assume that OBD Fusion is wrong about $06 data in my truck. What is $06 monitor anyway? How is it possible that I see misfires and dealer does not?
$06 monitor in OBD Fusion shows misfires in cylinders during 40 min trip on a second tank of Exxon 93 Premium Synergy+

C1 - 7
C2 - 1
C3 - 10
C4 - 5
C5 - 2
C6 - 5
C7 - 4
C8 - 2

 

[swathdiver]

How is it possible that I see misfires and dealer does not?

Gm equipment may be ignoring "misfires" that lack a certain intensity or frequency, the knock sensors can detect vibrations and other things happening around the engine bay and classify them as misfires. Take a hammer and rap on your exhaust manifolds while monitoring the knock sensors and see what happens.

 

[smokey_mountain]

Thank you. Any recommendation what tool should I buy/rent to monitor and log my truck?

Gm equipment may be ignoring "misfires" that lack a certain intensity or frequency, the knock sensors can detect vibrations and other things happening around the engine bay and classify them as misfires. Take a hammer and rap on your exhaust manifolds while monitoring the knock sensors and see what happens.

 

[Doubeleive]

I may need to ask for wisdom again...
I am reading that misfires in $06 monitor misfires should be zero. I only have OBD Fusion to read $06 but what is the tool that dealer would accept as evidence of misfires? What shall I buy to log misfires to present to the dealer? I posted above their results, they said zero misfires anywhere during dealer’s testing. I assume that OBD Fusion is wrong about $06 data in my truck. What is $06 monitor anyway? How is it possible that I see misfires and dealer does not?
$06 monitor in OBD Fusion shows misfires in cylinders during 40 min trip on a second tank of Exxon 93 Premium Synergy+

C1 - 7
C2 - 1
C3 - 10
C4 - 5
C5 - 2
C6 - 5
C7 - 4
C8 - 2

if there were misfires the ecm/bcm would store them in history and after enough misfires were recorded it would display a check engine light, that's how it works. whatever is happening is not enough for the computer to say "hey something is wrong". The Dealer lever scanner for these trucks runs anywhere from $1500-4000.00 and yearly updates are generally anywhere from $500 to $1000, there are some sub $1000 scanners out there but not sure what they are capable of compared to the better ones. I have been working with a $120 china clone tool for my 2018 but haven't got it to work quit right yet with gds2 the software is hacked and it's just been a pia.

 

[swathdiver]

Thank you. Any recommendation what tool should I buy/rent to monitor and log my truck?

For your truck GM is using the MDI2 with GDS2 software.

https://www.chinacardiags.com/wholesale/wifi-gm-mdi-2-diagnostic-tool.html

https://www.chinacardiags.com/whole...auxhall-opel-buick-and-chevrolet-for-win.html

Were you using an OBDII adapter of some kind with the DashCommand or Torque Pro application for smart phones?

 

[Kpwweb]

Just a thought. What if we threw misfires, etc out. What about cooling fan, or alternator, or ac compressor? Had an old Toyota with electric cooling fans. If you sat at a light long enough, the cooling fans kicked on and caused the alternator to start charging the battery, the idle would drop so much due to the load on the engine you’d thought the engine was going to die before it picked up again. Exhibited the same conditions you describe-warm engine, idle at light, vibration-but not all the time, etc.

At this point it might be worth it to start checking accessories and other items that would put a load on the engine under idle conditions.

 

[Doubeleive]

For your truck GM is using the MDI2 with GDS2 software.

https://www.chinacardiags.com/wholesale/wifi-gm-mdi-2-diagnostic-tool.html

https://www.chinacardiags.com/whole...auxhall-opel-buick-and-chevrolet-for-win.html

Were you using an OBDII adapter of some kind with the DashCommand or Torque Pro application for smart phones?

I bit, lol bought the mdi2 hopefully this will resolve my problem with gds2 not communicating using the vxdiag, I have the gds2 software running with 9542 days subscription lol

 

[swathdiver]

Just a thought. What if we threw misfires, etc out. What about cooling fan, or alternator, or ac compressor? Had an old Toyota with electric cooling fans. If you sat at a light long enough, the cooling fans kicked on and caused the alternator to start charging the battery, the idle would drop so much due to the load on the engine you’d thought the engine was going to die before it picked up again. Exhibited the same conditions you describe-warm engine, idle at light, vibration-but not all the time, etc.

At this point it might be worth it to start checking accessories and other items that would put a load on the engine under idle conditions.

His idle is a little low and the first thing tuners do is raise it 25-50 rpms. Low idle equals rough idle but as yet we cannot convince Dmitry to get BlackBear to tune it.

 

[Doubeleive]

His idle is a little low and the first thing tuners do is raise it 25-50 rpms. Low idle equals rough idle but as yet we cannot convince Dmitry to get BlackBear to tune it.

He should be able to get the idle to go up (for testing to see if it makes any difference) by turning on everything while parked, turning on all the lights, heater on full blast, flashers, windshield wipers, defroster, heated seats, radio, etc and let it sit a few minutes the engine should automatically idle up to stage 2 or 3, it should do it automatically to make the alternator spin a little more because of the amp drain.

 

[smokey_mountain]

Thank you for the links, this is an excellent alternative. I am comfortable with software. Will deep dive.

I was using KOBRA ODB II WiFi adapter with OBD Fusion and Torque Pro on my iPhone.

For your truck GM is using the MDI2 with GDS2 software.

https://www.chinacardiags.com/wholesale/wifi-gm-mdi-2-diagnostic-tool.html

https://www.chinacardiags.com/whole...auxhall-opel-buick-and-chevrolet-for-win.html

Were you using an OBDII adapter of some kind with the DashCommand or Torque Pro application for smart phones?

 

[smokey_mountain]

I have been watching carefully and documenting when I feel flutter - it happens even when truck sits idle in D or in P or N. In D it is more obvious. It happens during the day with almost no electrical load, with AC off, etc. and in the evening even if I push AC on with lights on. This morning on the cold start it was really skipping in 1200-1500 RPM, was really rough even with much elevated RPMs. It is dry and not humid. I am trying to drive to another dealer and drive 2020 Tahoe for 30 mins tomorrow and see if I am legally insane. Four dealers said that my truck is perfect. This is something to think about

I drove hard this weekend 360 miles round trip, kept it highway speed, accelerating and decelerating quickly.

 

[HiHoeSilver]

I have been watching carefully and documenting when I feel flutter - it happens even when truck sits idle in D or in P or N. In D it is more obvious. It happens during the day with almost no electrical load, with AC off, etc. and in the evening even if I push AC on with lights on. This morning on the cold start it was really skipping in 1200-1500 RPM, was really rough even with much elevated RPMs. It is dry and not humid. I am trying to drive to another dealer and drive 2020 Tahoe for 30 mins tomorrow and see if I am legally insane. Four dealers said that my truck is perfect. This is something to think about

I drove hard this weekend 360 miles round trip, kept it highway speed, accelerating and decelerating quickly.

Maybe after all this, you're just hyper sensitive like @LT1ZOB. He can hear and smell if you ate a potato chip in there a week ago.

 

[BG1988]

Dealer did check everything according to the work order:

• Engine mounts with picoscope
• Misfires cold and hot they said they see zero misfires on their equipment
• Injectors via afit test are all within 15% of each other
• Lugging/engine noise on the acceleration, not heard

Conclusion was - cannot reproduce any of my complaints. Truck is within GM specs. Advisor genuinely felt there is nothing that can do. Service manager was very accommodating and friendly but there is nothing that they can do.

I drove it for several hours since the pickup, absolutely no change, still misses as before, $06 monitor still shows misfires on cyl 7, cyl 6, cyl 4, cyl 3, cyl 1. Engine still makes noise on the acceleration up the hill in higher gear.

I think dealer did everything that they could without spending their own money. I respect them for that. I will take it on the longer drive this weekend and then if all the same - Nissan Armada is no longer as ugly as it was 3 months ago when I was buying this Yukon I will be crying at the pump but and when cruising at 70 mph. Yukon is just that super-plush.

I solved mine auto stop is working correctly for me

I gained 0.1 volts after a light cleaning the ground wires but they still need a deep cleaning ...





Have you tried higher octane fuel like 91 or 93?(you have to run it for a while to clear out the old 87oct fuel)


don't go to the cheapest station Mobil Exxon or chevron/texco I did notice AFM mode pings a lot with 87 octane even got stuck in the loop of death...

I been to other stations and they charged me 91oct prices for 87 octane ..


noticed after i pumped 9 gallons of the so called 91octane dropped the Timing advancement... by a lot before it was able to advance to upto 42 degrees, after pumping barely able to get to 25 degrees advanced that means my octane dropped to 88 to 88.5octane

 

[91RS]

I do also wonder if a tune will help you if they raise the idle a tad. My take on the fear of the warranty thing: you already feel like you're screwed on the warranty (at least with this particular concern) and if you're willing to lose $10k trading out of it, that $10k will pay for anything that might not get covered because of the tune. The probability of the tune being looked for anyway is pretty slim. It would really only matter if you had a major failure like the engine throws a rod. I say you have nothing to lose and everything to gain at this point. Blackbear says their tunes are undetectable anyway so I say go for it. A tune made a huge difference on all of my vehicles, I just used a local tuner instead.