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Discussion Starter · #1 ·
Hi Mazda 3 manias!!

I have a 2005 Mazda 3 with 2.3 l engine. I recently have been having problems with pinging noise in my engine. Here is how it happens....since I bough, I have been using 87 gas but recently I tried with 91 for once and then I have been using 89 for the rest of the time. However with 89 I have been hearing pinging noise when I am accelarating. Now I have to use 91 to get rid of the pinging noise. I wanted to go back to 87 but I was wondering if I need to repogram the computer to fit the 87 gas. Anyone has this problem before?

Is it expensive to have the computer reprogrammed? Do I need to do it through dealer or can I buy my own tool to repogram it. Please share your experience.

Thanks,
Deluxman
 

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This may be an issue for a mechanic. Pinging can be caused by several different problems.
· Timing that is too advanced (worn cam chain, worn out distributor shaft)
· Carbon build-up on valves (fuel injection issue, retains heat),
· Bad knock sensor
· EGR valve
· Hot engine (thermostat, water pump)

Good luck.
 

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Resetting the ECU's mapping is simple, just unplug the battery. It should relearn after some miles. It's a bad idea to use higher octane fuel than the car is designed for. Most non-turbo cars don't need (and can't benefit from) higher octane.

From what I've read, carbon deposits in the engine are most likely. Those will effectively up the compression ratio, making lower octane fuel more likely to detonate than burn. Not sure if there's an easy way to remove that that doesn't involve a rebuild. Maybe one of those engine cleaning foams?
 

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Discussion Starter · #4 ·
moverbaugh,

I know it is really not beneficial to use higher octane gas for mazda 3 but my first intention of using higher octane is to have better acceleration. Initially, my car is really weak when going uphill and also when trying to floor it on the freeway but when I use higher octane gas, it is a lot better. However, I tried using 89 gas for quite some time but now it starts to cause some cricket noise when I am flooring the pedal but since gas prices is going up again so I thought of switching back to 87 gas but I am sure it wil a lot of pinging in the engine.

I was told that the ECU might not recognize or be able to mix the air and gas properly since it is used to reading higher octane gas. But with your recommendation by just taking the battery plug and reconnecting will reset the CPU, is definitely an easy one. Please confirm if this will really reset the CPU. Also do you know if this step will also reset the TPMS as it is now seemed to be not as sensitive when I first bought my car. Now, even though I loss like 2-3 psi, the TPMS light will never light up.

I wonder if this has got to do with my tire rotation. I don't see any reset button either on the TPMS system. Any advise or tips are greatly appreciated.

Deluxman
 

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As for the TPMS:
http://www.mazda3forums.com/index.php?topic=109036.0

As to the high-octane gas, you'd really have to dyno the car to verify any performance difference. Since the 3 isn't really meant for it, I'd be surprised to see one, unless maybe your gas has a lot of Ethanol mixed in. For better low-end torque, you could try one of the smaller diameter CAIs. The stock airbox+resonator looks pretty restrictive.
 
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