Hey guys,
I got a mazda 6 (2017) that has the mileage of 27000 miles. I have engine knocks or pre ignition problem when I am accelerating, usually i hear the noise when the rpm is at 2000 and speed is above 20mph. If I speed up the noise will be gone.

I tried using different octane rating gasoline but still with the highest octane rating gasoline I have this noise. back to a month ago I had a error code of P0101 & P0172. one of them was the air flow code and the other the engine is rich. but after I reset the ecu there is no any fault code shown.

I even check the spark plug at a mechanic and he told me they were in a good condition. I also attached a sound file of the noise that you can hear it on the 00:03 sec.

Thanks for helping

 

Just a note, knocking is the same thing as detonation, what it is not is pre-ignition; pre-ignition is a condition which will destroy your engine within a matter of a few rotations.

• What country are you located in?
• What is the compression ratio of your engine?
• What grades of gasoline are available in your area and which grade rating system is used in your country (i.e. AKI, MON, or RON)?

 

Sorry for my misunderstanding, Therefore, i guess it is detonation noise.
- I live in Kurdistan, Iraq ( middle east)
- I don't know exactly, maybe it is 13:1 or 14:1. (how can I measure it while I have obd2 reader)
- We have three different gasoline:But gasoline quality here sucks, you can't find a decent quality.

 

Okay, as I understand it, all non-North American SkyActiv engines are running 14:1 compression ratio. Without knowing the MON and RON for the 95 and 97 fuels you can buy, I'm guessing your 95 *might* work and the 97 *should* work. If the car is still exhibiting detonation when running your 97, I would get to a Mazda dealership and have them diagnose the issue.

 

The problem starts here, I imported my Mazda from United states bought it in an auction.

The other problem is we don't have any Mazda dealership here, there are Toyota, Ford, and others but not Mazda.

I usually use the 95 and 97, but still, have the detonation.

How can I check my compression ratio? can it be changed by re programing?

 

If it is a U.S. car, then the engine has a 13:1 compression ratio, simple as that. No, you cannot change the compression ratio via reprogramming, compression ratio is a mechanical ratio which compares the volume of a cylinder when the crank is at BDC (relative to said cylinder) versus when the crank is at TDC (once again, relative to said cylinder); no programming in the world will change that. Now, there are techniques to get around the mechanical ratio by opening valves (or keeping them open) at seemingly strange times (not an option on your car), or you can retard the ignition timing via software, however, unless you have access to a Mazda dealer, it is unlikely you will be able to make a software change.

Next question, what spark plugs do you have in the engine? If they are the incorrect length and/or the incorrect heat range, detonation can be the result.

 

Last time I checked the spark plug, they were the genuine ones. I can take them out and take a picture if you need more detail!

I really appreciate your helping because I am about to sell the car if I cannot fix this problem which is bothering me!

 

I just check the owner manual of the American and Middle East version:Do a poor oil and oil filter effect the engine to make detonation?