Pinging on 87

[smokey_mountain]

2020 Tahoe LS with 5.3, 6-speed, 31K miles. I have tried Exxon, Mobil, BP, Shell gas in 87 grade and on 87 and often on 89 truck pings on highway trips, I am cruising 65-70 MPH, engine is always hovering around 1800-2000 and when I am trying to maintain the speed or add just a bit of throttle uphill it pings for 1-2 secs and then it downshifts and no pinging in the lower gear but once again at 70 MPH crusing around 1900 RPMs, if I am to touch the throttle it would ping/lug.
With 89 it happens less, with 93 no pinging.
I run Mobil 1 EP, Shell RGT, Valvoline Modern Engines oil with the AC Delco filter. Change oil every 4500 miles.

Dealer, of course, " cannot reproduce the issue". This truck is designed to run 87 fine and many on these forum run 87 with no issues, in my case, unless I run 93 it pings. Pinging is bad, thus what can I do to get the dealer/GM to accept the issue and fix it? With gas prices at $4.29 for 93 grade, it is now very noticeable to fill up. Appreciate thoughts.

Here is the Log file with knock events

 

[Bill 1960]

Get someone with a scanner / tuner that can read the timing and knock values in real time and go for a drive.

My guess is a faulty knock sensor.

 

[swathdiver]

2020 Tahoe LS with 5.3, 6-speed, 31K miles. I have tried Exxon, Mobil, BP, Shell gas in 87 grade and I hear pinging around 2000 RPM when I cruise and try to accelerate very lightly or to maintain the speed by light throttle going up the hill. Almost feels like it lugs. The noise is distinct loud ping from the engine for 1 second and as RPM go up it stops immediately, if I try to "lug" it pings. With 89 it happens a lot less, with 93 no pinging. I run Mobil 1 EP oil with the AC Delco filter. Change oil every 4500 miles.

Dealer, of course, " cannot reproduce the issue". This truck is designed to run 87 fine and many on these forum run 87 with no issues, in my case, unless I run 93 it pings. Pinging is bad, thus what can I do to get the dealer/GM to accept the issue and fix it? With gas prices at $4.29 for 93 grade, it is now very noticeable to fill up. Appreciate thoughts.

These are high performance motors and I know they say you can 87 in them, it just ain't right. Dmitry, right? What was that issue you had a year or so ago? Could it be related to this? If too much oil and blowby crud gets deposited on the pistons and chambers, it will raise temperatures and cause pinging/knocking.

 

[Jeff_]

I wish 93 was $4.29 where I live. It’s $5.40+ for 91.
All that being said, get a scanner and see what your knock sensor is doing.

I run 87 chevron and shell gas only and have never had issues like you’ve described.

 

[smokey_mountain]

These are high performance motors and I know they say you can 87 in them, it just ain't right. Dmitry, right? What was that issue you had a year or so ago? Could it be related to this? If too much oil and blowby crud gets deposited on the pistons and chambers, it will raise temperatures and cause pinging/knocking.

Hi @swathdiver yes it is the same Dmitry coming out but this time with a new problem on my 2020 truck , my previous truck was 2018 Yukon (that one could not hold idle steady.) I have traded-in Yukon for for this one, speaks to me liking this GM full size trucks and determined to get them to run well, but dealers are not helping. This 2020 one pings on all brands of 87. Catch can is certainly collecting quite a bit, I also did CRC valve cleaning just 3000 miles ago. That did not change pinging. I am trying to figure out how to check Knocking Sensor and rule it out.

 

[smokey_mountain]

I wish 93 was $4.29 where I live. It’s $5.40+ for 91.
All that being said, get a scanner and see what your knock sensor is doing.

I run 87 chevron and shell gas only and have never had issues like you’ve described.

In my state there was no Chevron, and to be honest it was by far the best 87 I had ever put in this truck, I was on a trip to/from FL and filled up there with Chevron, engine was smooth as butter and absolutely zero pinging. Exxon pings like mad. Shell is hit and miss, several times Shell did OK and no pinging but several times it did ping. I borrowed an iTuner, I found that I can log detailed data to the PC to review them incl. KR parameters. Maybe once I have these logs, someone here will be kind enough to evaluate my logs...

 

[smokey_mountain]

I have found logs from September 2021. I have them both as CSV as well as this zoomed out screen. I will collect new logs in the next 5 days but here is the data.

I am seeing KR events but not clear for me how to interpret them, from limited reading, KR events happen all the time or is not the truth?

Actual data is in this CSV file located here: Logs in CSV

 

[swathdiver]

I have found logs from September 2021. I have them both as CSV as well as this zoomed out screen. I will collect new logs in the next 5 days but here is the data.

I am seeing KR events but not clear for me how to interpret them, from limited reading, KR events happen all the time or is not the truth?

Actual data is in this CSV file located here: Logs in CSV

View attachment 354417

View attachment 354418

@randeez Hey Randy, would this include torque management or actual knock detected by the sensors?

 

[OR VietVet]

Whatever it is, you don't want to let it ping. What happens with a mix of 89 and 91/93? Here in Oregon I run that way too expensive 92 and 89 to try and reduce costs.

 

[smokey_mountain]

Whatever it is, you don't want to let it ping. What happens with a mix of 89 and 91/93? Here in Oregon I run that way too expensive 92 and 89 to try and reduce costs.

On pure 93 there is no audible pinging even when I tip in throttle (trying to "lug") a bit at 65-75 MPH to keep the vehicle steady or uphill, with 87 Exxon it pings regularly, with Exxon 89 it is occasional but does happen.
I have removed the catch can last night to diagnose further, from my early days I remember that PCV has no bearings on detonation but I want to eliminate all possible scenarios. Also did a bunch a usual checks.
Air filter is brand new 900 miles old, MAF sensor was cleaned with CRC MAF cleaner. Oil level is up to the top of a shaded/cross-hatched area of the probe.

 

[OR VietVet]

Have you tried the mix of 93 and either 87 or 89?

 

[STORMIN08]

so i have the exact issue you are referring to, i dont have the vehicle at my disposal daily to get logs, but i to have tried all levels of fuel octane...even mixes of several along long trips.

even tuned with 2 degress less timing, i still have the sound. i have been told it is actually the sound of the injectors, and not knock.

 

[randeez]

@randeez Hey Randy, would this include torque management or actual knock detected by the sensors?

should just be knock detected by the sensors.
not sure what you using to log, but i would log the total timingand knock retard as well, pretty common though from what ive seen. shows a lot of knock but doesnt really pull much timing, maybe a degree
DI crap is still pretty foreign to me, l83 is like 11:1 compression, half the time the knock is caused by too much fuel as they seem to like 12.5-13.0+ WOT
but if it goes away on 93.. i guess there's your answer

 

[Doubeleive]

should just be knock detected by the sensors.
not sure what you using to log, but i would log the total timingand knock retard as well, pretty common though from what ive seen. shows a lot of knock but doesnt really pull much timing, maybe a degree
DI crap is still pretty foreign to me, l83 is like 11:1 compression, half the time the knock is caused by too much fuel as they seem to like 12.5-13.0+ WOT
but if it goes away on 93.. i guess there's your answer

so what is a possible solution? run a slightly hotter plug?

 

[randeez]

i think gm uses it more as a predicted knock prevention during less ideal conditions, ideal conditions being rarely met

 

[OR VietVet]

I heard a GM trainer one time called it, "The sound of fuel economy".

 

[smokey_mountain]

should just be knock detected by the sensors.
not sure what you using to log, but i would log the total timingand knock retard as well, pretty common though from what ive seen. shows a lot of knock but doesnt really pull much timing, maybe a degree
DI crap is still pretty foreign to me, l83 is like 11:1 compression, half the time the knock is caused by too much fuel as they seem to like 12.5-13.0+ WOT
but if it goes away on 93.. i guess there's your answer

@randeez here is the total knock degrees and advance plot for the same log. I spent hours reading about KR plots but still cannot determine. To me looks like I have pinging but not sure.

 

[Trides]

Maybe time to get a Black Bear Performance tune?

 

[smokey_mountain]

Maybe time to get a Black Bear Performance tune?

I wish but Black Bear cannot tune 2020 trucks. They told me they never would be able to. I found that to be interesting as I am reading that DiabLew tunes 2020 successfully.

 

[Doubeleive]

Global B is a total lockdown thus far and probably will remain that way, it appears the whole system is integrated and letting a tuner in one portion probably opens pandoras box
they are concerned about security especially with a lot of vehicles going electric and wireless a hacker could cause a lot of problems.