2.5T Pings/Knocks w/87 Octane. Try to hear your engine if you have the same

thugzy

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2016 Mazda CX9 Signature, 2013 Merc GLK350 4Matic, 2001 S2000
A while back I posted on here that I was hearing a ticking sound, during acceleration, under boost around 2500-3500rpms. When in Park, if I was to rev the engine up to those rpms, there was no ticking noise.

I took it to the dealer at 3000kms on the odometer and left it with them overnight and a day. They replicated the noise and said that it is a common noise on engines that have a valve/flap that regulates the intake pressure. In the 2.5T's case, the dealer is saying the intake manifold (dynamic pressure system). They had no fix, and said it was normal....also commonly heard on the MS6 engine from what they say.

So ever since then I decided to switch over to no lower than 91 octane fuel for the added hp bump (which is very noticeable above 5000rpms btw)....to my ears, the ticking noise went away after 3 or 4 tanks using 91 Octane.



....NOW, I'm at 11,000kms.... I just recently filled up with 87 octane after the tank was empty. Low and behold, the ticking noise is back.......

my 2.5T pings or knocks!.... this is surprising since 87 is the minimum recommended fuel.


I am asking my fellow owners if you hear the same ping/knock noise from the engine with 87 Octane. Do the following:
-Radio off
-HVAC off
-find a quiet location
-windows up
-from a stop accelerate fairly aggressively up to 2500rpms and holding the boost/rpms around 3000rpms

I hear the noise coming in front of the passenger side engine bay when driving.

I need to know if this is an isolated case with my vehicle, or is this something common.

Thanks All!
 
I run 87 all the time, and have not heard this, but I will check this afternoon.
 
I've only used 87 octane and have never heard any knocking.


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87 octane and no such noise. having said that, i have never let the gas go down to empty.
 
Tried to duplicate your situation today, no pings. 87 octane, warm engine, 7 degrees Celsius today.


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Haven't noticed any issues with mine though I've only had my vehicle for over 2 months so might be too early to tell...also I recently switched to using premium gas and while it is not required I don't mind paying the extra cost since we only put in low mileage on it and the extra $20 per month won't break the bank
 
Haven't noticed any issues with mine though I've only had my vehicle for over 2 months so might be too early to tell...also I recently switched to using premium gas and while it is not required I don't mind paying the extra cost since we only put in low mileage on it and the extra $20 per month won't break the bank
But there is no point in doing so. If you actually use the added horsepower at max rpm, OK. Otherwise, spend your money more wisely.
 
But there is no point in doing so. If you actually use the added horsepower at max rpm, OK. Otherwise, spend your money more wisely.

I have always used Shell V Power even with my previous Volvo...i know it is not necessary but I don't mind using prem gas not only for the added hp but also for the added benefits such as having cleaner engine deposits and the additives to help protect against gunk and corrosion and etc. We can debate this but at end of day it's my money and I can spend as I wish...besides it's only $20 more per month for me and this is a $50K vehicle so the extra cost is not as significant
 
OP, it is hard for others to replicate the exact test, also each individual has different sensitivity to noise. Can you try with 87 octane from a different brand or a busier location? If problem remains, try test drive on a dealer vehicle.

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Maybe I'm out of place and need to stick to my own generation of cx-9 threads, but is this a Ford motor? My work vehicle which is a Ford Escape 1.6T ecoboost has always pinged a little. Even my CX-9 3.7 motor pings a little on 87 octane until I toss in a can of seafoam and run several tanks of 89. I feel like a lot of the 87 especially in multi-branded fuels (sam's, Kroger, speedway, etc) is just not a great fuel to use in any vehicle. They design these new turbo charged motors to "accept" 87 fuel, but that doesn't mean your motor is going to like it. If I had a new 2.5T I'd run a higher octane if for nothing else to prolong engine life.
 
Sound like really cheap fuel.

Knocking, ticking, etc. is very bad for a forced induction motors as that's normally a lean condition. LEAN = Bad...very bad / RICH = Not Bad...computer is compensating and making fuel adjustments to be safe.

Either fill up with 93 octane to see if the noice is still there or dump a can of octane booster in it now (while it's full).

I bet the noise goes away with higher octane. Lots of fuel stations water their gas down with Methanol. There are warnings on the pumps here in the States.
 
Maybe I'm out of place and need to stick to my own generation of cx-9 threads, but is this a Ford motor? My work vehicle which is a Ford Escape 1.6T ecoboost has always pinged a little. Even my CX-9 3.7 motor pings a little on 87 octane until I toss in a can of seafoam and run several tanks of 89. I feel like a lot of the 87 especially in multi-branded fuels (sam's, Kroger, speedway, etc) is just not a great fuel to use in any vehicle. They design these new turbo charged motors to "accept" 87 fuel, but that doesn't mean your motor is going to like it. If I had a new 2.5T I'd run a higher octane if for nothing else to prolong engine life.

No, this is not the Ford motor. this is a brand new Mazda-engineered engine 2.5L Turbo 4-cylinder in the new (16 and 17 CX-9).
 
I've run Shell 87 octane for over 7k miles and haven't noticed this issue.
 
Can you not use a datalogger like Torque to see if it will read knock values from your car? If your car was knocking, you would definitely notice it and you will feel the loss of power as the ECU will pull timing to try and save the engine.
 
Most modern engines have a knock sensor that the ECU uses to monitor fuel quality - the ECU constantly adjusts the ignition timing and other parameters (boost pressure, etc.) to be right at the threshold of knock.

It isn't surprising that you started hearing pinging when you switched to 91 from 87 - the engine was running with parameters that the ECU found that worked with 91 octane gas. If it doesn't stop, you either have a problem with the engine, or the gasoline you are using is <87 octane and the ECU can't pull enough timing to fix the issue.

Personally, I'd stop buying gas from whatever station you bought the "87" octane gas from and try another. I have a Subaru that needs 93 octane gas or it pings like crazy - some gas that is "93" octane works fine while gas from other stations results in mild detonation. It's possible that for whatever reason, your engine is slightly more sensitive to fuel quality than others on here.
 
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Can always disconnect the battery for a few hours to reset the ECU.

Maybe it'll relearn the fuel parameters.

Still sounds like bad fuel. Put some octane booster in it with 87 or fill up with 91 or higher. I bet it the noise goes away.

If it doesn't you tell Mazda you've tried everything and the noise persists. Don't leave until it's fixed.

Ping / Knock is not good. Detonation on a forced induction can do harm after time.
 
Thanks to all for the replies.....I recently burned off that tank of 87 from Esso and filled up with 87 Shell.... will report later
 
Did this rectify itself? I am having a similar issue with 33 degree celsius heat and 91 ron unleaded..... only shown up since the heat.
 
Did this rectify itself? I am having a similar issue with 33 degree celsius heat and 91 ron unleaded..... only shown up since the heat.

Hey Foxy,

We bought our Azami in Feb this year and it was pretty bl00dy hot for the first few weeks we had her. There was no no pinging or knocking in our car when running on 91. Having said that, I noticed that on 98 octane the fuel consumption improved sufficiently to cover the extra cost of the premium fuel so we only ever fill her up on 98 these days.

Its possible that the fuel economy was going to improve anyway as the engine ticked over 5K km, but from what I understand fuel quality in Australia isn't the best so I figured we might as well not risk the lessor fuel on the 9.

Good luck.
 
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