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

Why is everyone using 87 octane fuel?

As long as you are using ethanol free 91 fuel, youre going to save on fuel to the point where the extra cost for 91 is almost completely negated, especially considering that you get an extra 40 HP from switching. This helps get the car up to speed more effortlessly with less throttle and the car will run better.

Its either you people stick to one type of fuel or the other, try not to switch back and forth too much
 
1. Can always disconnect the battery for a few hours to reset the ECU.

2. 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.

1. No. never reset your ECU like this.

2. The ECU will adapt and change parameters on it's own within 400KM
 
U.S. & Canada gasoline octane numbers are 4 to 6 numbers lower than other parts of the world, because a different measuring scale is used. Australian 91 is very similar to U.S. & Canadian 87.
 
Any update Thugsy?? When mine does this the clicking noise is very obvious and loud, from centre RHS of the car......
 
I'm noticing something similar with my 2.5T CX-5, and I was wondering if they are related.

I started noticing a knock sound when I'm stopping. It always happens when it slows down to around 12 to 10 mph. When it happens, the car also jerks very slightly.

I noticed the noise when my car reached about 2000 miles. Now that I think about it, it's also around the time when I switched from premium to regular gas (after reading premium gas doesn't make a difference unless it's over 4000rpm). I never realized that it could be related to gas. I'm going to try switch back to premium again, and see if the noise goes away.
 
Your engine is under zero load while you are slowing down or stopping. Whatever you are hearing, it isn't pinging or detonation.
 
I'm noticing something similar with my 2.5T CX-5, and I was wondering if they are related.

I started noticing a knock sound when I'm stopping. It always happens when it slows down to around 12 to 10 mph. When it happens, the car also jerks very slightly.

I noticed the noise when my car reached about 2000 miles. Now that I think about it, it's also around the time when I switched from premium to regular gas (after reading premium gas doesn't make a difference unless it's over 4000rpm). I never realized that it could be related to gas. I'm going to try switch back to premium again, and see if the noise goes away.
Agree with jal142. Knock would happen at high RPM and high engine load. Your description sounds like the transmission downshifting as you slow to a stop, which is normal behavior for automatic cars. Transmissions are mechanical components and clunk noises are common when the gears engage. Give it a listen at low speeds with the radio and air turned off; at high speeds wind and road noise drown them out but they are still there.

Side story related to vehicle noise: ask a Nissan engineer how much R&D money went into developing windshield wipers for the all-electric first gen Leaf. With no engine noise to cover it up, even seemingly small systems like that become annoyingly noticeable.
 
I fill with Shell 93 when I can find it.

I just drove cross country. With 93, I averaged low 20s high 19s MPG. When only 87 was available, I dropped to high 16s low 17s. I was running the car at 80+ MPH; when running 87, I suspect that the engine pulled timing which resulted in lower power and lower MPG.

I spent 2008-2018 in North West Europe was gas was >$10 per gallon. I have no problem with spending a few extra cents for 93 here in the US.
 
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 use 89 octane in our 08’ C9 - we occasionally run Lucas upper cylinder lubricant injector cleaner in the gas and it really helps… we just rolled over 300,000 miles and she is still going.
 
Might want to try a field additive and go with a different gas station “top tier.”

I personally run bg44k as my fuels additive every other fiLl. I when gas was creeping around $5 a gallon for regular I filled with regular but didn’t notice any pinging. Now the prices have come down approximately dollar I fill with 93 octane. Can’t speak about improve gas mileage as I don’t do many highway mileage. If you’re going to run 87 octane gas and experience pinging I’d recommend running a fuel additive. Also if you’re experiencing the thing the pinging noise while decelerating that’s not pinging that’s some thing else entirely different.
 
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