Mazda 3 woes - 2020

Gaz012012

Hi,

Engine Malfunction sign came on car and i was already booked for service at main dealer so they completed diagnostics. They have provided a quotw for £1500 for injector cleaning.

Any thoights on the price and also suprised at 6 years with 32k miles?

I have tried a few local garages to try to get chraper, but they seem not keen

daveyjp

Some clues as to the exact Mazda 3 especially the engine type may illicit a useful response.

Gaz012012

Thank you

• Make/Model: Mazda 3 GT Sport Tech MHEV 4X4 Skyactive - x
• Engine Size: 1998cc (2.0L)
• Fuel Type: Petrol Mild Hybrid (MHEV)

daveyjp

Very likely due to carbon build up on the injectors. Owners club is a good place to research the issue.

Goudy

That sounds quite excessive for cleaning injectors so I presume it probably includes stripping and cleaning the intake and intake valves.

Direct injection engines don't pass fuel though the intake and over the intake valves, only air, recirculated exhaust from the EGR system and a little blow by oil vapour from the crankcase pass though. Fuel as the name suggests is injected direct into the cylinders.

Unfortunately, the recirculated exhaust and oily blow by from the crankcase vent cause carbon to build up in the intake and on the intake valves and with nothing to clean it, you start getting a problem.

Older cars tended to have a different injection system, so fuel passed through the inlet and inlet valves and would have a certain cleaning effect.

It's normal for direct injection engines to suffer some build up but certain Mazda engines are notorious for carbon build up on the inlet and inlet valves and require stripping and cleaning.

I'm not quite sure why these Mazda engines suffer, maybe it's due to the EGR system design or how it's programmed to operate but it's a common problem and will documented. 32,000 miles does seem quite low for this, but I have read of them requiring attention as low as 15,000 miles.

Gaz012012

Thanks for that info, its £600 for the labour. Ive called 5 so far and none seem wanting to quote so may just have to suck it up and pay main dealer price. Ill try a few others first

westv

I thought Mazda engines were bullet proof but I have seen on YT mention of carbon build up on DI.

Is seeing it on a 6 year old car unusual?

Goudy

https://forums.moneysavingexpert.com/discussion/comment/82124132#Comment_82124132

I think there's a bit of a giveaway. 32,000 in 6 years. I'm guessing that's a lot of short tripping which is never good for a motor. Engines never fully warming up properly and low rpms around town could well likely add to the issue.

I have a similar aged DI engine from a different brand which isn't noted for it, but you never know. It's just a characteristic of these types of engines, some designs are more prone to certain conditions I guess.

Mazda tend to be very progressive with their engineering. They tend to stick with something then constantly improve (kaizen). I've read they have improved things on their later engines to combat the issue, like changing the PCV system and rerouting the EGR system to introduce less carbon. I even think they've changed the combustion and valve arrangement to allow the valves to run much hotter to help with carbon sticking.

facade

Unfortunately Mazda have moved to direct injection petrol engines, which are always Trouble.

Since no-one else will touch it, most likely you have the Skyactiv-X variant, which is unnecessarily complicated. (But super powerful and economical for the length of the warranty) Dealer labour rates are very high.

Direct injection engines are often needing to have injectors and inlet valves cleaned at ridiculously low mileages I'm afraid.

forgotmyname

Some of those Skyactiv engines are not upto their usual standards. Some are good but in the bid to get the
emissions lower and lower they had to tweak the engines and killed the reliability.

Piston rings with low pressure/friction on the cylinder bores allows more oil past the rings which then enters the
inlet system and the coimbustion chamber.

These have been covered by several youtubers on which ones to buy and which ones to avoid.

Gaz012012

I have now got the diagnostic report (doeant mean a lot to be fair to me but have looked at the codes and appears to correspomd). Managed to find an alternative garage so will see what they say