Ticking sound and white smoke

[Yullia]

My Mazda 2016 CX-3 1.5L Diesel has several problems: Knocking (a ticking sound) when pressing the accelerator and brief white smoke from the exhaust during startup. Injector adaptation temporarily helps, but the issues return after about 30 km.

The DPF and EGR systems were recently removed. The injectors and the entire fuel system have been thoroughly checked and confirmed to be in good condition. Despite all this, the problems persist.

Has anyone else experienced similar issues?

 

[Carlos T]

Hello.
I have the exact same noise. It happens between 1000rpm and 1500rpm by pressing the accelerator lightly and white smoke from the exhaust during cold startup .

It started to happen sometimes and would disappear for a while but now is always there. Just like you, DPF and EGR were removed, injectors and the entire fuel system have been thoroughly checked and the problems persists.

One thing i've noticed is that i-stop is not working (sometimes it works out of nothing) and that leads me to believe that the knocking sound has something to do with the reprogramming of the ECU (car computer) after DPF delete and is messing with fuel injection timing or performing ghost regeneration of the DPF thinking is still there.
Either that or something with injectors (despite test machine says otherwise) or carbon build up somewhere.

Did you get to find out what was causing that knocking sound?

Thanks

 

[kingvanisle]

I know when I had something similar noise wise on my 2016 CX-3 at around 125k Km, it was a 3rd cylinder spark plug issue. The plug was mostly good but had a hairline crack in the ceramic that was the source (noticed with OBD readout).

But since you know injectors and fuel system are good my next guess with that amount of white smoke could be a blown head gasket or even cylinder head issues?

 

[Carlos T]

I may be wrong but I don’t think the 1.5 diesel has spark plugs. As to the head gasket wouldn’t I noticed milky oil or constant smoke? The smoke I have is only for a few seconds at cold start and not as bad as yullia’s video.
Regarding cylinder head… don’t know but car runs fine with no power loss.

 

[N7turbo]

That could be a symptom of a valve stem seal letting a little oil seep into a cylinder. Enough collects to burn off noticeably when you start it, otherwise, if it's a very slow leak the smoke may not be visible. Same goes for a piston ring.

Keep an eye on your oil level.

For the sound—does the car shake when that happens? I hear some vibrations. Did that start before or after the emissions removal?

 

[Carlos T]

I have thought about valve steam seals before but the oil consumption is not so bad. Around 50ml-75ml per 1000km.

And if it was valves wouldn’t the noise be present at idle or other range of rpm?

The car does not shake and I can’t confirm if the noise started after the dpf delete cause I bought the car with the dpf off already and the noise is present since, although in the beginning it would appear for 2 weeks and it would disappear for another 2.

The car always have run fine (and still is) but the noise always happened in the 1100-1500rpm and it appears more easily uphill or if I press the gas pedal more abruptly (not lightly like I said before).

By lightly i mean maintain the gas pedal pressed in the same rpm (mainly uphill) when the noise happens

If I press it abruptly (uphill and flat) the noise appears for a brief moment and goes away as the rpm rises.

I have heard in other forums that the I-stop goes crazy if a wrong reprogramming is done after dpf delete but this kind of knocking sound could be anything and is driving me crazy.

 

[N7turbo]

But in your video, it comes across as a vibration coming from dash panels.

 

[Carlos T]

It is not but I can see how you heard it. Audio in video can be misleading.