2018 CX-5 Carbon build up?

[vrsick]

They put in the ngk plugs and ngk coil. I bought 3 more coils to replace myself for less than the 1 they put in. waiting for the CEL issue to resolve first.

Keep us posted for the end result...

 

[Mazdiod2]

That looks about what I would expect at 130,000 miles.

Your shop has it opened up enough to clean the valves right now. Just have them clean them.

It looks like you could clean them, maybe with a wooden stick.

 

[gman1]

So I finally got my car back after taking it to the dealership. They did a BG 2 step cleaning but it didn't fix the issue. The cel came back on and they replace the ngk coil with their OEM coil and the misfire and limp mode resolved. The carbon buildup problem diagnose by CBA was an easy target for the engine misfire and a nail they can always find to hit with the hammer but the culprit was the non-oem coil. My car is running a bit rough at times (not consistent) when shifting gears so I am hoping it is the residual BG fuel induction service solution going thru the system that is causing it. But no more CEL.

 

[Jmaz]

I still think of NGK being one of the quality manufacturers. Don't know where you sourced that coil but ebay and Amazon have been accused of selling counterfeit parts.

 

[gman1]

I still think of NGK being one of the quality manufacturers. Don't know where you sourced that coil but ebay and Amazon have been accused of selling counterfeit parts.

It was installed by Christian Brothers automotive, a repuable mechanic shop.

 

[cz5gt]

I dealt with similar issue on a non-mazda turbo DI car recently. The valves were all in gunk but that was not the issue. The pistons also had some gunk - looked inside with a camera.
The problem came up after spark plug change. Turned out one of the new spark plugs (oem) had micro crack (probably over tightened) which eventually blew the coil. Changed with all new spark plugs and new coils and problem solved.
No more misfire. Then some good 93 fuel - few tanks and lots of highway higher rpm and all good for now. Looking in the piston again with camera showed they self cleaned a bit. Funny but the valves never were issue even with all the gunk.

 

[vrsick]

I fear having similar issues with carbon deposit. My other vehicle Rav4 V6 2008, I always used 89 oct and mostly 92 octane. After 15 years, I took apart the car top head, and to my surprise, it was spotless. Now that I have my new 2024 CX-5, I will be adding premium only, and cross my fingers I have no issues.

 

[N7turbo]

I fear having similar issues with carbon deposit. My other vehicle Rav4 V6 2008, I always used 89 oct and mostly 92 octane. After 15 years, I took apart the car top head, and to my surprise, it was spotless. Now that I have my new 2024 CX-5, I will be adding premium only, and cross my fingers I have no issues.

Unfortunately, fuel grade will not make a difference. All we have are 1) how we drive and 2) eventually cleaning it.

 

[vrsick]

Unfortunately, fuel grade will not make a difference. All we have are 1) how we drive and 2) eventually For me , it's 1) I drive alot of highway.

 

[gman1]

I dealt with similar issue on a non-mazda turbo DI car recently. The valves were all in gunk but that was not the issue. The pistons also had some gunk - looked inside with a camera.
The problem came up after spark plug change. Turned out one of the new spark plugs (oem) had micro crack (probably over tightened) which eventually blew the coil. Changed with all new spark plugs and new coils and problem solved.
No more misfire. Then some good 93 fuel - few tanks and lots of highway higher rpm and all good for now. Looking in the piston again with camera showed they self cleaned a bit. Funny but the valves never were issue even with all the gunk.

So after driving it a bit with the new spark plugs NGK 93501 LKAR7BIX-11S and OEM coil, I noticed the car feels heavier and sounds deeper when I hit the gas. Sometimes flooring it will get the RPM up but not the speed. It does not drive the same as before. I had these exact spark plugs previously and got 55k miles before having it replaced with the same ones. Does it sound like I have bad plugs? I also got the BG 2 STEP INDUCTION SERVICE done at the same time so I'm not sure if it loosen up the carbon gunk in the valve and that's causing the performance issue. I tried to redline it a bit and noticed a strong burning smell afterwards.

 

[cz5gt]

unlikely to be the plugs. I would vote for the bg whatever service they did. Likely they used some chemicals for that (btw the real cleaning is only walnust blasting, the chemicals dont work that well and can do more harm). Drive few hundred miles (preferrably highway and with high octane) and see how it goes.
Oh and change the oil as soon as possible. Its recommended after such chemical treatment.