Issues after misfuelling 1.5 diesel

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Percy247
Posts: 144
Joined: Sun Nov 10, 2019 4:08 pm

Post by Percy247 »

1st regen since oil change after 210 miles. Car was doing 70mph on motorway and instant consumption fell from 60-70mpg to 30-35mpg for 10 minutes. Car felt very sluggish during the regen. From this am I correct in thinking the engine only does active regens and does not perform passive ones?

From looking on this forum and Mazda 3 forums the common problem seems to be faulty injectors causing over fueling. Can I check/recalibrate the injectors with forscan and a simple usb dongle?
Has anyone done this with any success or otherwise?
2016 Mazda 2 Sport Nav 1.5 Skyactiv Diesel.

Percy247
Posts: 144
Joined: Sun Nov 10, 2019 4:08 pm

Post by Percy247 »

Just an update for the one person who still has a diesel on this site.

Took the car out yesterday for a 60 mile run and the car was really struggling up hills on a part throttle for the first half of the journey. It felt well down on power, so I detached the MAF sensor to test it. This made no difference and threw up three warning lights, so I replaced it.

On the way back at 65 - 75mph on the motorway the car felt more responsive.

Today I cleared the fault codes and recalibrated the injectors with Forscan. I then took it out for a quick Italian tune up and ran really well with no signs of power loss under load. Hopefully, the fuel additive is starting to work.
2016 Mazda 2 Sport Nav 1.5 Skyactiv Diesel.
Bodger
Posts: 1
Joined: Sat Nov 19, 2022 9:16 am

Post by Bodger »

Hi just found this thread and wondering how you are getting on, any major improvements or any parts failing?
The reason I ask is my wife has just added 20 litres of petrol to her CX3 1.5 Diesel, it had 1/2 tank of diesel already so about 50/50 mix.
Didn’t realise until 10 miles later when it Kangeroo’d to a halt.
Our local garage towed it back, drained it & flushed it but there are some scary stories & advice about changing the whole fuel system. £2k to £5k!!!

Please let me know how you got on.

Many thanks
Percy247
Posts: 144
Joined: Sun Nov 10, 2019 4:08 pm

Post by Percy247 »

We still have the car but in the last 3 weeks fuel consumption, dpf regen frequency and duration have all increased. I don’t think this is related to misfuelling (but it could be) as the car has been fine for a year with no problems. I suspect I now have a DPF issue and think it might be a faulty differential pressure sensor, carbon build up in the EGR or intake manifold or soot accumulation in the dpf brick.

Anyone else had similar issues? Any thoughts or suggestions (clean MAP/MAF or reset PCM) and can anyone recommend a DPF specialist in North Yorkshire or the North East?

The guy who drained our tank was pretty confident there would be no long term damage but you never know! I believe one Wayne Rooney misfuelled his Overfinch Range Rover Sport and the bill for flushing the fuel system was £5,000. Basically, I need to get ours fixed and sold.
2016 Mazda 2 Sport Nav 1.5 Skyactiv Diesel.
Percy247
Posts: 144
Joined: Sun Nov 10, 2019 4:08 pm

Post by Percy247 »

I have done a bit of digging and it appears that there are two issues with the 2.2 and 1.5 skyactive Diesel engines but there is a lack of a consensus between the actual cause and symptoms.

Firstly, these engines rely heavily on the EGR system to reduce NItrogen oxides. The emissions fix software update of 2017/2018 basically increased the amount of time and rev range that the valve is open for. This means more soot is being recirculated around the engine and emissions system. Over time it will build up and ultimately get so bad that it causes restrictions and blockages which throw a DTC error code. The extra soot also causes the DPF to fill up sooner and regeneration intervals to be reduced. This cycle continues until again a DTC appears when the regen intervals are down to about every 30-40 miles or so.

Secondly, there is known problem with some of the Denso injectors that are used in these engines that both Mazda and Denso refuse to acknowledge. Any goodwill payments from Mazda are dependant on you surrendering your old injectors to stop you having them independently tested. The injectors suffer from cavitation which causes irregular spray patterns and poor combustion. This further increases the soot emissions and exacerbates the problems of soot build up in the intake manifold and emissions system.

What is not clear is whether it is the bad injectors that are the cause or that it is the soot build up that raises engine temperatures and causes the injector failure. The cost of replacing all four injectors and coding them is over £2000 and any goodwill from Mazda will depend on the age of your car, service history and ultimately how much the Service Manager at your Mazda dealer will fight for you. Emissions and intake systems might also need cleaning and/or replacing!

If you are curious and want to check the state of your EGR and intake manifold then it really easy. All you need to do is remove the 4 bolts holding the 8 inch shiny metal pipe at the front of the engine (watch out for the metal gasket on the EGR side). Remove the pipe and inspect both ends for soot accumulation and clean. Now shine a torch down the hole on the left into the inlet manifold and see how much soot you can see. Mine looked pretty bad!

I then checked my MAP sensor which was very clean. I think this is due to it being not directly in the airflow. I very briefly ran the engine from cold and the valve on the EGR opened partially and fluttered open and closed repeatedly. I was expecting it to open fully from cold. Does this mean the EGR is working properly or not? I also checked Forscan and the most recent regeneration started after 127 miles which is not as bad as I thought.

My conclusion is that these engines are a ticking time bomb and sooner or later they will hit you with a wallet destroying bill.
2016 Mazda 2 Sport Nav 1.5 Skyactiv Diesel.
Graeme67
Posts: 107
Joined: Wed Apr 14, 2021 8:37 am
Location: Sunderland UK

Post by Graeme67 »

I checked the EGR pipe on mine a few months ago, and it was the same, thick black oily soot deposits. I cleaned what i could see with some brake cleaner.. Don't think these problems are unique to Mazda, All modern diesels are like this due to strict emissions and to be fair petrol engines suffer from a lot of carbon build up too, Especially with this new E10 petrol. I know VW had a lot of problems with their diesel engines with the introduction of DPF's. Injector failure, Overheating. EGR valves used to clog up and fail, The list was endless.. Modern diesels contain all this soot, where older diesels would vent some of it out the exhaust.. The main problem with diesels is the EGR system, Basically the engine is breathing bad oily sooty air back through the combustion process..... I think the EGR valve is closed during a cold engine but opens when the correct temp is reached, It also fluctuates during acceleration... I've started to use a diesel additive (Millers diesel power ecomax) every time i fill up. Don't know if it helps but willing to try anything to keep the engine internals clean.. I only use the car for short journeys which doesn't help but every couple of weeks i give it a run down the A1 to hopefully clean it out..
2017 CX 3 1.5 Diesel Sport Nav
Percy247
Posts: 144
Joined: Sun Nov 10, 2019 4:08 pm

Post by Percy247 »

I think the analogy “sniffing your own farts” perfectly describes the workings of the EGR. I have been using diesel additive for about a year now and don’t know whether it is doing any good. I am tempted to remove the EGR valve and give it a clean.
2016 Mazda 2 Sport Nav 1.5 Skyactiv Diesel.
Graeme67
Posts: 107
Joined: Wed Apr 14, 2021 8:37 am
Location: Sunderland UK

Post by Graeme67 »

I was going to use that phrase but thought it a bit iffy ha ha... Yep i was thinking the same about the EGR valve, Can't hurt to give it a good clean, going to try and keep it clean as it might prevent problems in the future.
2017 CX 3 1.5 Diesel Sport Nav
Percy247
Posts: 144
Joined: Sun Nov 10, 2019 4:08 pm

Post by Percy247 »

My main problem is that most of our journeys are either less than 5 or between 15-20 minutes which makes a regen difficult to complete.

With a regen pending, I warmed the car up for a few minutes today before setting off about 2 hours later. The car got up to temp within 1 minute and the regen started. I made a conscious effort to keep the revs above 2K and the regen completed in 13mins 35 seconds. Is this the best way to drive during a regen? I presume had I driven in a higher gear and at lower revs, the regen would have taken longer (and I would have arrived before it finished!).

Now I have just noticed a knocking sound from the suspension! I have just had both bumpers resprayed, new discs and pads and 2 new tyres. It looks like the bills will keep on coming!
2016 Mazda 2 Sport Nav 1.5 Skyactiv Diesel.
Graeme67
Posts: 107
Joined: Wed Apr 14, 2021 8:37 am
Location: Sunderland UK

Post by Graeme67 »

I think keeping revs up during a regen creates more heat in the exhaust/DPF helping to burn off any particulates. Mine takes roughly a similar amount of time to complete but i've noticed since using the diesel additive, It seems to take a little longer, might be wrong but just seems that way... My suspension knocks when turning either right or left on rough roads. Sounds like vibration through the springs.
2017 CX 3 1.5 Diesel Sport Nav
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