What I know is this the fuel I purchased in California had my car pinging all the way down the road not to mention low octane to boot. When ever I visited Arizona I would fill up with fuel and the pinging would stop. I moved to Chicago because of a job change and noticed higher octane fuel and my pinging stopped altogether. I don't know what the fuel in California has or doesn't have but it was destroying my engine one ping at a time. I tried additives and octane boosters and it helped a little bit. I understand California has the toughest pollution laws in the country, but really. Performance sucks...

Bill

 

Pinging is usually an indicator that the octane is too low, not the "quality" is too low.

What octane have you been putting in your car up to now?

Our cars require 91 or greater.

 

91 or greater on the LS3, 93 or greater on the LS2, LS7 and LS9, and could be worse if the car was re-tuned for octane even higher.

As for the ECM table, there are high and low octane tables that the car will kick back to if the octane rating is not high enough to start with, to reduce the spark advance, but some times the problem is if the fuel has ethanol in it (say up to 10% in some places) since the C6 does not have a E85 flex fuel sensor in it, and does not do well on high levels of ethanol in lower octane fuel to begin with. Also, if you are trying to run say 85 octane, going to be problems as well.
Note, ECM does have flex fuel tables in it, but since the C6 does not have a flex fuel sensor, the table are not used instead.

So to sum it up, kind of like the guy that goes to hospital, tells the doc that it hurts when he moves in a certain way, and the doc just tells him to stop moving that way. Hence in your case, you know the correct higher octane fuel solves the ping problem, but continue to run the lower octane fuel that is causing the problem in the first place.

Also, find top tier fuel stations to fuel up the car!!!
The top tier fuel stations have cleaner in their fuels, and prevent the fuel system from having problems like ejectors clogging up.
Most of use prefer chevron stations since they use Techron in the fuel as the cleaning agent, but other brand of top tier fuel cleaning agents work just as well.
https://www.toptiergas.com/licensedbrands/

 

I agree with owc6 that this sounds like an octane issue, not a quality issue. The octane problem in California is that due to the CARB gasoline specs, it’s more difficult to generate high octane gas there than it is elsewhere. As a result of that problem, almost all premium in California is 91 rather than 93 octane. Your knock sensors and ECM should make timing adjustments to allow use of 91 without pinging, but if your knock sensing system is a bit out of whack, perhaps it couldn’t handle the adjustment properly. When you moved to Chicago, premium went up to 93, solving your problem. Your Arizona experience is a bit muddier. Most gasoline in Arizona comes from California refineries. Prior to about 2014 (I forget the exact year), it was even required to be CARB spec, so would have been 91 for sure. Thus, prior to 2014 I would have to resort to far out speculation on why Arizona premium should behave any better than California. But about 2014, Arizona stopped requiring full CARB spec. Thus, premium in Arizona now is 91 some places and 93 others. So odds are, your Arizona experience was because you were getting 93 in Arizona.

Dano523 is partially right about the timing adjustments, but I would quibble about two minor aspects of what he said. First, the high/low octane tables are not an either/or choice. If knocking is sensed, it interpolates between high and low tables until the knocking stops. So for example, if your fuel is just a bit low on octane, it might be running 80% high table plus 20% low table. Once it gets all the way to the low table, if it’s still knocking, then you’re out of luck. The other thing I’d quibble about is that presence or absence of ethanol has nothing to do with knocking or the knock sensing system. The only thing that matters is blended fuel octane. If knocking is sensed on the fuel you are running, it moves things further toward the low table. The ethanol sensing device that is in some (not all) flex fuel vehicles is mostly to help adjust air to fuel ratio faster when switching between E85 and normal gas. The reason for the hedge word “mostly” is that some of the latest flex fuel systems are more sophisticated and would take a long explanation. The point for this thread is that ethanol is not related to the pinging described in this thread.

 

[QUOTE= I understand California has the toughest pollution laws in the country, but really. Performance sucks...

I would say that your experience is anecdotal - meaning it is your car. If California gas was so bad, then you would have tons of posts from California owners saying that their cars ping. I don't recall a single post about that.

 

My car (LS2) pings under hard acceleration. I Always use top tier gas but as noted above, in CA we can only get 91 octane.

 

I'm not quite as technical as you. My car has an LS2 in it and I have been using 91 octane in California. I have also added octane boosters with no improvement. I do know increasing octane does not automatically improve performance or even lessen engine pinging. I do know engine pinging is fuel pre detonation and is corrected by fuel burn slowing agents mixed in with our fuel. There is a substantial difference from state to state when it comes to fuel quality and I feel California has the worst fuel probable because of all the EPA additives and restrictions. I currently live in Illinois due to a job change. Fuel octane has increased to 93% straight out of the pump with 10% methional during the summer months. Not only does the fuel outperform California fuel it even smells different. Faster acceleration, zero pinging and better mileage overall. I do agree Chevron has a great fuel and I tried to use it when ever possible. Less pinging to boot. Bottom line is I have never run 85 octane fuel in my engine and probably never will. We all try to do the right thing when it comes to our vetts. But some States fuels are just bad. I draw the line at $6.00 fuel additives just didn't make sense to spend $45.00 for fuel and then add expensive additives that make big promises and deliver nothing.

 

 

Just got back from 1,300 mile round trip to Northern California from Southern Nevada in mine, with over half those being in California; with few exceptions, the highest octane you can find in both states is 91. I have made this run numerous times to visit family over the years in both my Corvette & Camaro; have never experienced any pinging after filling up at stations in California; cars run great with no noticeable change in performance. I would have to say it is either your car or where you are buying your gas.

 

[QUOTE=Bob Paris;1597841577][QUOTE= I understand California has the toughest pollution laws in the country, but really. Performance sucks...

I would say that your experience is anecdotal - meaning it is your car. If California gas was so bad, then you would have tons of posts from California owners saying that their cars ping. I don't recall a single post about that.[/QUOTE]

91 octane in California is probably equivalent to 87 in other states. I have only used Chevron in my LS3 since new and now I think I'm having clogged fuel injector issues. I've not experienced "pinging" but the fuel quality in this state sucks.

 

Bill, Pretty lengthy rant considering you never mention what the octane of the fuel was. CA sells 91 octane at just about every outlet, and that is more than adequate for your car. I am betting that you mistakenly filled up with 87. Corvette owners all over CA complain about the price of gas, but not the quality, or octane rating. Their cars run fine, and yours should have, too.

 

[QUOTE=RRichards83;1597868708]Richard (or Bob P, but I think it was your comment)....91 octane in CA is equivalent to 91 octane in other states. Yes, there are other issues with gas in CA, but the octane is the octane.

 

BDM_10 , lets cut to the chase.

If the car still running the stock air intake system, still running a stock tune, and have run enough Tier one fuel or techron added to the gas every few tank fill ups to keep the fuel ejectors clean.

If yes, then pull the MAP sensor and connector off and clean them, and pull the MAF to clean it as well. Also check the air filter to make sure it clean, the spark plugs for fouling and gap problems (as well to make sure they are oem), and when you have the plugs out, scope the top of the pistons for the amount of carbon build up on them and even do a compression test to make sure all the cylinders have the same compression. Hence we could just do a quick data log to see where the problem is, but since it going to point back to one of these items, may as well just jump in front of it instead.
Note, If you where having problems with either the crank or cam sensors, then would be a bunch of codes thrown throw for such.


If aftermarket parts/tune, then on the after market air filter system, could be causing problems with the MAF readings to begin with since the air intake system is causing too much turbulence at the sensor, and if a tune, could be that tables were tweaked too high to run on high octane fuel and the problem isntead on standard fuels. Hell, could be that the motor was build with higher compression, and may need octane upwards of 100 before it will run it max instead.
To add here, high mileage cars tend to have a higher carbon build up on the pistons, which will end up oil soaking as well, which raises the octane requires of the fuel due to more motor oil in the combustion area.

Hence more details on the car, will help us pin-point the problem with getting knock of standard 91 octane fuels (not matter if the fuel is 10% ethanol or not).

 

[QUOTE=Bob Paris;1597841577][QUOTE= I understand California has the toughest pollution laws in the country, but really. Performance sucks...

I would say that your experience is anecdotal - meaning it is your car. If California gas was so bad, then you would have tons of posts from California owners saying that their cars ping. I don't recall a single post about that.[/QUOTE]

Mines been pinging for a few yrs owned it since new in 02. Maybe theres something to what he says?

Yrs ago could let my old schooler sit for yrs gas was fine. Now? No more than a few mos it wont ignite at all.
I agree it is crap

USed to be Id visit AZ and the car would feel like it dropped 50hp due to DA..

 

[QUOTE=cuisinartvette;1597870967]You probably don't want to visit Denver or Albuquerque then....LOL.....

 

Pretty sure they cannot legally sell gas advertised as one octane, but it really isn't. Certainly not state-wide for years. I would follow what Dano said, as it sounds like there is some specific problem with your car and the other guy's car.

It's been pinging for years??? That's not good, I would get it fixed ASAP.

Your gas won't ignite after it sits for a few months? That sound ridiculous.

 

FWIW I use Shell's highest octane in my 2013 LS7 427 505HP Anniversary Edition. I think they call it Ultra. Car runs like an Elk and never knocks.

 

buckmeister2
Thanks for your reply. I have never put 87 octane in my tank and the pinging has been going on for years and only on California fuels. Even Arizona 91 octane fuels resolves my pinging problem. According to some of the other posts my vette has had a diet of Chevron and Shell fuel since I purchased it. It has been at the dealer several times and have also switched dealers a few times to boot and the problem remains. It tends to be a little better on Chevron fuel. I'm not sure what the problem is but I do know that the problem occurs so far only on California fuel. I'm not even sure if other people are having this problem. From the sound of these posts it is only my car that is having these problems and all the other vettes in california are fine.

 

Yours is a later year my is the first of the 2005's. So yours may have been corrected by the time 2013 rolled around.

 

BDM_10 , again, your LS2 should run fine on 91 octane fuels, and even with them up to 10% ethanol.

If the car is pinging on CA fuel (it does have 10% ethanol), then something is going on with the sensors or tune to cause the problem.

So if the car is all OEM, then pretty easy to go through the main sensors like MAF and MAP to clean and check them, so the ECM is seeing the correct readings.
Injectors are easy to keep clean with top tier fuels, or you can add Techron to the fuel as well. air filter is easy enough to maintain, and as well if the pistons are starting to get a high enough carbon/oil build on them as well.

As for after market parts, and even a tune, where is where things get a bit strange, since you really want to have the car tuned for where you are running it (at that sea level) and on the fuel your going to run in it as well. Hence the Map tables (how far you are above see level, hence atmospheric pressure that the engine is seeing) are not bad for the stock tune since it leave in a lot of room for error, but when you start tuning for the edge, and change the altitude of the car, the ECM tables can end up with the car running on the lean side, and can cause the knock problem. Same goes for fuel, since ethanol take 30% more fuel than petrol for the same burn, and if the car was tuned for straight petrol, and now you running 10% ethanol, the motor is going to run on the lean side as well. Compound the problem with the Maf (amount of air being pulled in) and the MAP (the atmospheric pressure of the air being pulled in) sensors not reading correctly, and this leads to problem with detonation problems as well.

And again, a lot of after market air filter intakes are know to cause problems with the Maf sensor not reading correctly as well. This is the reason when you install an after market system, you really want to get a tune of the car to correct the Maf sensor readings. If all you did was just install say a oiled filter like the K&N filters, they tend to get over oiled, and end up coating the MAF so it not reading correctly (why you want to clean the Maf). Hell, the sparks plug fouled or not gapped to .040" can cause problems as well.

So to sum it up, what is OEM on the car and mileage, what is After market (including maybe a tune) and the problem is really easy to solve with the pinging problems you are having on different 91 octane fuels. Hence the LS2 really wants to be run on 93 octane pure petrol fuel to produce it most power when OEM, but should not have pinging problems on 91 10% ethanol fuel, since it has low octane tables that is can adjust down to as needed when needed to prevent the ping problem in the first place.