Mazda6 2.0 petrol - Pinking when hot

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Thu 2 Jan 2014 21:50
Mazda6 2.0 petrol - Pinking when hot - kiss (keep it simple)

Hi Backroomers.

I have a 54 reg Mazda6 2.0 petrol with 124k on the clock. Since about 100k I have noticed quite a lot of pinking, worst when hot and in hot weather. The car has been used mainly for long runs. It also feels a little lethargic and definitely feels hesitant when cold. This makes me think it is running lean. Economy is good, 38mpg average. I have tried the following

1. New MAF sensor. (tried cleaning the old one, only slight improvement.

2. Tank of super unleaded.

3. Diagnostic check. All ok.

We did a trip to Italy this summer and the pinking was quite evident under part load 2500-3500rpm. I was a bit concerned that I could damage the engine but it survived 3000 miles.

Does anyone have any ideas?

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Thu 2 Jan 2014 22:26
Mazda6 2.0 petrol - Pinking when hot - craig-pd130

A small air leak in the inlet trunking after the MAF filter, possibly?

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Thu 2 Jan 2014 23:22
Mazda6 2.0 petrol - Pinking when hot - kiss (keep it simple)

Thanks for the suggestion. I will have a look!

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Thu 2 Jan 2014 23:24
Mazda6 2.0 petrol - Pinking when hot - elekie&a/c doctor

Does it use a lot of engine oil ?

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Fri 3 Jan 2014 09:23
Mazda6 2.0 petrol - Pinking when hot - Collos25

Used to be sign of overheating engine faulty thermostat used to be the main culprit or it could be the ignition is to far advanced.

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Fri 3 Jan 2014 19:35
Mazda6 2.0 petrol - Pinking when hot - kiss (keep it simple)

The engine uses little or no oil.

Can the timing drift on modern engines? I thought the ECU took care of all that. Temp gauge stays bang in the middle when warmed up, but maybe it's lying. Thanks for the advice, everyone. I will see what I can find out.

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Fri 3 Jan 2014 19:47
Mazda6 2.0 petrol - Pinking when hot - elekie&a/c doctor

Are you sure it is pinking?Could it be the inlet manifold flaps rattling.Unlikely to get timing drift on modern engines.The electronics will retard the ignition if noise/knock in the engine is detected.

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Fri 3 Jan 2014 19:55
Mazda6 2.0 petrol - Pinking when hot - kiss (keep it simple)

Are you sure it is pinking?Could it be the inlet manifold flaps rattling.Unlikely to get timing drift on modern engines.The electronics will retard the ignition if noise/knock in the engine is detected.

Well I suppose that is a possibility. Any way I can be sure either way? That wouldn't explain the hesitation when cold and a slight loss of power, though. Perhaps they are unrelated. The other possibility could be carbon deposits causing hot spots, but I avoid short runs. My regular commute is dual carriage way and motorway.

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Fri 3 Jan 2014 22:15
Mazda6 2.0 petrol - Pinking when hot - Big John

Anti-knock sensor?

Could also be a partially blocked/damaged catalytic converter. Common issue if car has had any mis-fire issues in the past.

Just a couple of thoughts...

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Fri 3 Jan 2014 23:01
Mazda6 2.0 petrol - Pinking when hot - kiss (keep it simple)

I had thought about the anti knock sensor and mentioned it to my indie dealer about a year ago when it was in for service. He said the diagnostics were all clear. Similarly, would a damaged cat show up on the MOT emissions test? Again, no problems reported. I have owned the car since 60k and never had any misfire. Is 124k getting on a bit for a cat?

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Sat 4 Jan 2014 08:11
Mazda6 2.0 petrol - Pinking when hot - Collos25

124k is quite a high mileage for a cat it could also be the cause of your noise which you describe as pinking.

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Sat 4 Jan 2014 10:14
Mazda6 2.0 petrol - Pinking when hot - Big John

Recently had the cat replaced on my old 2001 Octavia 1.4 as it had rusted through causing an exhaust blow. Obviously this fixed the exhaust blow but also transformed the performance of the car. It was also cheaper than I expected.

This car did have a coil pack failure a few years ago causing it to misfire for a while (two short journeys) on two cylinders, however it has never failed an emissions test.

Edited by Big John on 04/01/2014 at 10:20

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Sat 4 Jan 2014 21:30
Mazda6 2.0 petrol - Pinking when hot - Collos25

About 100 ukps for a cat for this model reasonble price .

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Sat 4 Jan 2014 19:31
Mazda6 2.0 petrol - Pinking when hot - Cyd

Could be the engine is coked up. When it gets hot the coke cause pre-ignition.

Find a good indie garage that has an inspection camera they can put through the plug holes to see what the internal state of the engine is. If it is coked up, try a treatment of Slick 50 engine cleaner (miraculously this worked for me on a previous car) and run it continuously on Shell V-max.

Also clean out the throttle body and inlet tract.

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Sat 4 Jan 2014 21:31
Mazda6 2.0 petrol - Pinking when hot - Big John

"Could be the engine is coked up. When it gets hot the coke cause pre-ignition"

This used to be a big issue a few years ago when you needed to perform regular de-cokes. I ran an old Zephyr V6 that ran on for minutes sounding like a lumpy diesel long after turning the ignition off. I thought with modern petrol this was generally a thing of the past.

I am aware that some direct injection petrol cars can still be prone to carbon deposits though but I don't think a Mazda 6 2.0 Petrol has this.

Re inspection cameras - I bought one of these cheap from Aldi a while ago and it is really useful. Great for checking the state of the plastic & rubber vacuum pipes on my Skoda Superb or even checking under a floor to trace a wet-room water leak. The camera is on the end of a flexible tube with an LED light on it and would fit through some spark plug holes.

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Sat 4 Jan 2014 21:38
Mazda6 2.0 petrol - Pinking when hot - Big John

Nearly forgot. When I did de-coke the Zephyr it solved the running on but I always felt the performance was never as good after that. Can't be sure why but I wondered if it was the reduction of the compression ratio after I had removed rather a lot of carbon.

Edited by Big John on 04/01/2014 at 21:47

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Sat 4 Jan 2014 22:38
Mazda6 2.0 petrol - Pinking when hot - Cyd

Actually, inspection cameras can be had so cheap off eBay it might be cheaper to buy one and diy than taking it to a garage.

A lot less common certainly, but still possible. The symptoms are right.

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Tue 25 Nov 2014 21:44
Mazda6 2.0 petrol - Pinking when hot - 230kmazda

Hi.

I have exactly the same issue with my 53 reg Mazda6 2.0 petrol with 230k miles on the clock.

Have you found a cure for the pinking noise and loss of power when cold?

All The best

John

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Thu 27 Nov 2014 11:41
Mazda6 2.0 petrol - Pinking when hot - kiss (keep it simple)

Hi John

No it's pretty much the same as ever. Now on 140k still with all original exhaust etc.Passed the last MOT in July with no issues. I am impressed with your 230k. Have you needed any engine work?

Gareth

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