6.2 hates regular gas

[Russell Holmes]

Just want to know If any one else has the same issue as me.

 My 2018 GMC has 148000 km on it now and has has hated regular fuel since new. The salesman never told me they required premium fuel. So its first 2 tanks we regular and it pinged and sputtered put premium in all problems gone. Now if I can't get premium and have to put in regular the check engine light is on until I can get a full tank of premium then it goes off in under a kilometer.

  Her is the strangest part once my Dad drove my truck he traded his 6 month old 5.3 for a new 6.2. I told him he needed to burn premium he told me no! He has 150 000 kilometers on his now gets better fuel mileage then me and only put premium in when he is pulling a trailer maybe and it never pings. 

 

 My truck does pull harder

[1SLOW1500]

Reset fuel trims and even trans then let the pcm relearn. Also all gas isn't equal and the number on the pump is just a idea of octane ratings. I always run premium in everything.

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[Bash74]

So unless a vehicles needs it because of stuff like compression ratio, detenation, or tuned for it, there is no need to use it. Did a graduate project that took a little over a year to do with 4 new vehicles. 2 left at factory specs, 1 tuned, and 1 high compression engine vehicle. The project had to do with this exact subject and it concluded that it is not worth it to use premium unless the engine had to have it because of the things I list. The one big comparison that came up in the test is when we filled up with 85 octane, which is readily available in Colorado because of altitude, then towed the vehicle to South Texas, there was some issues. These tests where conducted during, all seasons, at multiple different altitudes, on the street, multiple dyno runs, and towing. This was not exactly a new study, just went about some of it in a different way. When all said and done it just was not worth the cost, especially when talking about performance that was within a small margin of error. This study just confirmed what so many other studies and people have talked about. Gas companies know it gives people warm feeling using it and they capitalize on it. Oh and midgrade is the fuel companies just slapping people in the face. Now like I tell people all the time with everything, if that's what you want its your money do whatever you want with it.

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[Russell Holmes]

9 minutes ago, Bash74 said:

So unless a vehicles needs it because of stuff like compression ratio, detenation, or tuned for it, there is no need to use it. Did a graduate project that took a little over a year to do with 4 new vehicles. 2 left at factory specs, 1 tuned, and 1 high compression engine vehicle. The project had to do with this exact subject and it concluded that it is not worth it to use premium unless the engine had to have it because of the things I list. The one big comparison that came up in the test is when we filled up with 85 octane, which is readily available in Colorado because of altitude, then towed the vehicle to South Texas, there was some issues. These tests where conducted during, all seasons, at multiple different altitudes, on the street, multiple dyno runs, and towing. This was not exactly a new study, just went about some of it in a different way. When all said and done it just was not worth the cost, especially when talking about performance that was within a small margin of error. This study just confirmed what so many other studies and people have talked about. Gas companies know it gives people warm feeling using it and they capitalize on it. Oh and midgrade is the fuel companies just slapping people in the face. Now like I tell people all the time with everything, if that's what you want its your money do whatever you want with it.

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I agree with all that you say. My father's truck has had 4 o2 sensors and a combustion clean??? What ever that is. My truck 0 maintenance other then oil changes. I just can't figure out why my truck pings and losses about 3 mpg on regular. I also can't figure out why GM would build a truck that is required to burn premium fuel. It says in the owners manual burning regular will void engine warranty!!

[1SLOW1500]

You may have different trans or gears or wheel size. Even same setups can be different in the ve or trans tables. There is a adaptive learn built in that shifts around the settings based on use. So it's all your fault.[emoji38]

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[TJay74]

I hate to say this but if you are running the 6.2 around on 87 instead of the 91 that is clearly says on the gas cap door and in the owners manual that is required, not recommended then you are taking a chance on having ignition related detonation damage done to the engine which GM has now outlined in the owners manual if that happens they may not fix it since it will be due to using the incorrect fuel.

The 5.3l trucks really should be on premium as well, from brand new these trucks have always had pinging and detonation when running 87 octane. I have logged several trucks over the years doing it, it is worse the hotter it is outside versus the cooler to colder months outside.

Just the word to the wise, run it as you want but taking the chance to me isnt worth the $5-$10 savings per tank of gas. If the gas mileage is of that much concern to you then a truck may not of have been the best vehicle choice.

[Russell Holmes]

Gas mileage is an issue when your putting 6000 to 8000 kilometers a month on but I need  truck. We move house structures heavy haul truck is always loaded. Still way cheaper to run this truck then the diesels we had before

[flyingfool]

21 hours ago, TJay74 said:

Just the word to the wise, run it as you want but taking the chance to me isnt worth the $5-$10 savings per tank of gas. If the gas mileage is of that much concern to you then a truck may not of have been the best vehicle choice.

actually there is absolutly no cost savings by using 87 octane, it actually cost more per mile to burn, kinda like running e85 in a stock truck and hoping for good mpg.. you want effiency and good mpg, run 91 always!  people cant drive, and the more horsepower the modern cars make , takes more fuel to burn.  drive the speed limit and use V4 mode and cut back on your coffee intake. 

[Black02Silverado]

One thing to try is find a gas station that has a high turn over of fuel. That way it is always fresh also find one that is Top Tier. 

 

To me these new trucks have a high compression ratio.  I know the computer can control everything but compression is compression and if you try to run a low octane fuel you are just asking for problems.  Maybe not now but if you keep the vehicle for a long time it will show up later. 

 

Even Justin from Black Bear Performance told me that if anything run 89 octane and up.  This is from an individual that see's a ton of these vehicles come in to be tuned and he can see what the conditions are from the computer.  If it wasn't a big deal he wouldn't recommend it.

[flyingfool]

On 11/3/2019 at 9:02 AM, 1SLOW1500 said:

Reset fuel trims and even trans then let the pcm relearn. Also all gas isn't equal and the number on the pump is just a idea of octane ratings. I always run premium in everything.

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how do we reset fuel trims?

[1SLOW1500]

You can reset the whole pcm or tb %. Meaning after warm up (180egt) you have to bring the throttle up and then let off. Forgot the %. It is in my software. I changed.mine to be lower so it resets more and without being in boost.

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