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the damn engine pinging and sound like a metal heat shield is rattling. WTF!


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I’m assuming you have a 2011 mdx based on your username, please fill premium as the gas cap says required. The owners manual also says to use premium but once in a while regular is fine but not continuously. It also states engine may ping if you keep using regular gas. As for the rattling, try checking underneath and see if the shield is rattling. There was a post regarding this. You will also save at most maybe 150 dollars a year using regular gas over premium which is not worth it imo over a engine issue.


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Discussion Starter #3
I’m assuming you have a 2011 mdx based on your username, please fill premium as the gas cap says required. The owners manual also says to use premium but once in a while regular is fine but not continuously. It also states engine may ping if you keep using regular gas. As for the rattling, try checking underneath and see if the shield is rattling. There was a post regarding this. You will also save at most maybe 150 dollars a year using regular gas over premium which is not worth it imo over a engine issue.


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Yes it’s 2011. No, it is not the heat shield. I have this issue with 89. My X is so sensitive to pinging on 89 octane.


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Ok 2011BlackUbmX The 2011 MDX is a high compression Engine! It has 11:1 Compression Ratio ,It was NOT built to run on 89 Octane Period! This unfortunately happens more often then people will let on! True... the car will run on 89 octane but as you and others have found out it will run poorly causing a knock/ping noise in your engine! This will not be noticed right off the bat for inexperienced ears but be assured it is definitely taking place! This goes unheard the first time as one is mixing low octane with high octane and is less noticeable at first. This becomes a Real Problem over time as you and others on this forum have found out as you experience reduced performance and the dreaded detonation noise which in no uncertain terms is"Destroying Your Engine"! This detonation is responsible to destroying pistons, spark plugs and rod bearings over time! In extreme cases you can damage your Catalytic Converters which will be evident in them rattling almost like in your words a" heat Shield"/ Climb under and have a listen to your cat back system and check if a heat shield is loose? You can use a broom handle or such to see if it stops rattling?

I can understand that individuals want to save at the pump but this is No Place to save when you have a vehicle that requires 91 or Higher Octane fuel. The $10.00 savings a tank will cost you exponentially more in repair costs or engine failure. There is no immediate concern if you pull into a gas station and they do not have 91 octane and you put in 89 octane so you can get home, but do not fill it up with 89 octane if you do not have to. Instead put in what you need to get you to your destination and then fill up with the proper 91 octane fuel!


Those that claim they used 89 and nothing happened after they used 89 octane they are correct when they say they did not notice a difference and the reasons why are listed above. It is what you do not always hare or see that is the problem.



Proper Octane Use is essential to maintaining your vehicle reliability and its performance and should not be Skimped on unless you are prepared to pay the repair bills that come with trying to save on gas costs! You will lose ever time in this situation so heed the warnings and fuel up with specified Octane rating by the manufacturer for your Specific vehicle!
Remember you can always use higher octane in a vehicle designed for 87-89 octane although the added cost would be a waist but going the lower Octane in a vehicle designed for higher octane 91-94 octane "IS Going to Ultimately Damage your vehicle! The saying you can pay the bill now or pay it later holds very true, but it is entirely your decision!
 

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Must be related to driving style. Once I was in a gas station in the middle of nowhere. The price gap between 91 and 87 must be more than 70 cents. So I gave 87 a chance and nothing happened for the next 300 miles on the highway. That was the only time I used something other than 91 or above.
 

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If there is more than a 50 cent difference a gallon i'll mix premium and regular at a 2 to 1 ratio. This comes out to exactly 91 octane. Saving $2.50 on a fill-up is a large Dunkin coffee :smile2:
 

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Must be related to driving style. Once I was in a gas station in the middle of nowhere. The price gap between 91 and 87 must be more than 70 cents. So I gave 87 a chance and nothing happened for the next 300 miles on the highway. That was the only time I used something other than 91 or above.


That is exactly what I did. I was running out of gas in the big city and saw a gas station at the corner and the price for 93 is $3.85 and 89 is $3.25. So I opted for the 89 for 8 gallons until I got out of the city where the price for 93 is $2.85 at Speedway.


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That is exactly what I did. I was running out of gas in the big city and saw a gas station at the corner and the price for 93 is $3.85 and 89 is $3.25. So I opted for the 89 for 8 gallons until I got out of the city where the price for 93 is $2.85 at Speedway.


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It might be quality of the gas other than octane. I always stick with Chevron or Shell.
 

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Ok 2011BlackUbmX The 2011 MDX is a high compression Engine! It has 11:1 Compression Ratio ,It was NOT built to run on 89 Octane Period! This unfortunately happens more often then people will let on! True... the car will run on 89 octane but as you and others have found out it will run poorly causing a knock/ping noise in your engine! This will not be noticed right off the bat for inexperienced ears but be assured it is definitely taking place! This goes unheard the first time as one is mixing low octane with high octane and is less noticeable at first. This becomes a Real Problem over time as you and others on this forum have found out as you experience reduced performance and the dreaded detonation noise which in no uncertain terms is"Destroying Your Engine"! This detonation is responsible to destroying pistons, spark plugs and rod bearings over time! In extreme cases you can damage your Catalytic Converters which will be evident in them rattling almost like in your words a" heat Shield"/ Climb under and have a listen to your cat back system and check if a heat shield is loose? You can use a broom handle or such to see if it stops rattling?

I can understand that individuals want to save at the pump but this is No Place to save when you have a vehicle that requires 91 or Higher Octane fuel. The $10.00 savings a tank will cost you exponentially more in repair costs or engine failure. There is no immediate concern if you pull into a gas station and they do not have 91 octane and you put in 89 octane so you can get home, but do not fill it up with 89 octane if you do not have to. Instead put in what you need to get you to your destination and then fill up with the proper 91 octane fuel!


Those that claim they used 89 and nothing happened after they used 89 octane they are correct when they say they did not notice a difference and the reasons why are listed above. It is what you do not always hare or see that is the problem.



Proper Octane Use is essential to maintaining your vehicle reliability and its performance and should not be Skimped on unless you are prepared to pay the repair bills that come with trying to save on gas costs! You will lose ever time in this situation so heed the warnings and fuel up with specified Octane rating by the manufacturer for your Specific vehicle!
Remember you can always use higher octane in a vehicle designed for 87-89 octane although the added cost would be a waist but going the lower Octane in a vehicle designed for higher octane 91-94 octane "IS Going to Ultimately Damage your vehicle! The saying you can pay the bill now or pay it later holds very true, but it is entirely your decision!


The pinging only occurred in the first 2-3 minutes during acceleration from a dead stop. And as long as I don’t turn off the engine and kept driving and stop and go in traffic I don’t hear any more pingings. Now if I turned off the engine at stop lights and then restarted the engine and continued driving, the pinging is coming back during acceleration. Strange phenomenon.

Now the pinging is gone after I filled up with 93. But i still hear a quieter pinging with 93 when I do a lot of start and stop driving.


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2011BlackUbmMDX correct me if i am wrong but you have previously claimed that you are burning oil as have many others on this forum as i recall? Keep in mind that if you are burning oil it is taking place in the combustion chamber and while this is happening you are more than likely getting some carbon build up at the same time in the offending cylinders! It may be one cylinder or maybe all of them? This can be due to poor piston ring to cylinder bore seal or from leaking valve guides that allow oil to pass and carbon buildup unfortunately will/does occur in these situations! This carbon buildup on top of the piston or cylinder head and valves can cause pre-ignition or detonation. So there are other conditions that can cause pre- ignition or detonation in our engines.


If one already has carbon build up a lower octane fuel will only add to the problem! Be aware that Lower Octane fuel by itself is not a common contributor of "Carbon build up" as fuel has undergone great changes through the years to prevent this event from occurring on its own. The problem that arises when you are burning oil in the cylinder is what else is effected in our modern Engines? I mention a few areas to be concerned when one has a oil burn problem and how it effects the engine as a whole.



I know... I know we all want the quick and easy fix but there is a reason you start with basics , test, and eliminate it as the cause before moving onto the next area of troubleshooting. The potential for spark plug fouling is a real issue which can cause poor starts. Possible EGR fouling and carbon build up in it are very real and If the vehicle is used for short trips you can only add to it! While this is all going on your vehicle is trying to compensate for the shortfalls which can/does mask things making things a little more complicated if you do not know what to expect?



So your pinging is not just related to running 89 Octane on a regular basis but other factors are at play as well! One should be aware that switching back to 91 or 93 octane is a good thing but do not expect miracles after the fact as damage from prolonged detonation is unfortunately not reversible :(
 

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Discussion Starter #11
2011BlackUbmMDX correct me if i am wrong but you have previously claimed that you are burning oil as have many others on this forum as i recall? Keep in mind that if you are burning oil it is taking place in the combustion chamber and while this is happening you are more than likely getting some carbon build up at the same time in the offending cylinders! It may be one cylinder or maybe all of them? This can be due to poor piston ring to cylinder bore seal or from leaking valve guides that allow oil to pass and carbon buildup unfortunately will/does occur in these situations! This carbon buildup on top of the piston or cylinder head and valves can cause pre-ignition or detonation. So there are other conditions that can cause pre- ignition or detonation in our engines.


If one already has carbon build up a lower octane fuel will only add to the problem! Be aware that Lower Octane fuel by itself is not a common contributor of "Carbon build up" as fuel has undergone great changes through the years to prevent this event from occurring on its own. The problem that arises when you are burning oil in the cylinder is what else is effected in our modern Engines? I mention a few areas to be concerned when one has a oil burn problem and how it effects the engine as a whole.



I know... I know we all want the quick and easy fix but there is a reason you start with basics , test, and eliminate it as the cause before moving onto the next area of troubleshooting. The potential for spark plug fouling is a real issue which can cause poor starts. Possible EGR fouling and carbon build up in it are very real and If the vehicle is used for short trips you can only add to it! While this is all going on your vehicle is trying to compensate for the shortfalls which can/does mask things making things a little more complicated if you do not know what to expect?



So your pinging is not just related to running 89 Octane on a regular basis but other factors are at play as well! One should be aware that switching back to 91 or 93 octane is a good thing but do not expect miracles after the fact as damage from prolonged detonation is unfortunately not reversible :(


Thanks for the in-depth diagnosing the problem. I think I have found a partial solution to my oil consumption. After I have been using Prestone engine restore for about 1-2 months I noticed oil consumption improvement. See the picture



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I know someone who destroyed a BMW by using regular gas when the car calls for premium unleaded. Ultimately the car randomly stalled or randomly won't start. The same person that says his car does not need synthetic oil. He gets away with regular oil, but did not get away with regular gas.

Back to topic, I ran into a Mobil station that sells regular gas as 93. Perhaps a mistake by delivery driver, but it happens.

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We loaned our car to a family friend recently. One thing my wife forgot to tell was that the car takes super but I did not know. When the MDX was returned it was pinging like MAD! I was very worried and concerned and started to back track, ask wife questions, etc... then I came to know it was the last tank of gas her friend put in the MDX...REGULAR.

Why skimp on gas when you purchase a $50K car?
 

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I mistakenly filled up with 87 last week and had no pinging or engine hiccups but power was down a bit. Mpg seemed low as well but only ran it for half tank before refilling with 93.
 
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