High RPM on cold start

I bought a second hand 2018 Mazda CX-5 2.2 diesel skyactiv AWD in August 2022. It has now 78.000 km.

Since I bought it, it always revved up the engine automatically to 1800 rpm on cold start for around 10 seconds and then slowly goes down to idle. I thought this was because the engine was cold. The thing is, lately it randomly does it or not. I can't find a pattern. I just find it weird that with the low winter temperatures it sometimes doesn't rev up.

Is this expected?

Thanks!
 
I bought a second hand 2018 Mazda CX-5 2.2 diesel skyactiv AWD in August 2022. It has now 78.000 km.

Since I bought it, it always revved up the engine automatically to 1800 rpm on cold start for around 10 seconds and then slowly goes down to idle. I thought this was because the engine was cold. The thing is, lately it randomly does it or not. I can't find a pattern. I just find it weird that with the low winter temperatures it sometimes doesn't rev up.

Is this expected?

Thanks!
I don't believe that is normal. I have a 2019 (North American) 2.2 diesel and mine does not behave in your described manner. On a cold or warm start mine will hit maybe 1100 rpm but be back at normal idle within a second or two.

If the car for some reason is trying to enter an "active" regeneration it will rev to 2000 rpm and hold it there for about 10 minutes to burn off the DPF. Most of the time it can accomplish a DPF regeneration in the "passive" mode which you won't even know is going on.

I assume since you didn't mention any error messages or warning symbols illuminated there are none?

I use the phone app "forscan" with a bluetooth dongle plugged into the OBDii port to tell me everything I need to know what is going on inside my car. Pressures, temperatures, levels, etc. Great tool for $6 !
Yes. It is written in the user manual.
dunda may be speaking about the gasoline engines. I have not seen that in the user manual for the diesel.
 
I have a diesel version (2.2, 175, 2016).
In Slovenian user manual: "Po zagonu hladnega motorja število vrtljajev motorja naraste in iz motornega prostora se zasliši cvileč zvok. To se zgodi zaradi dodatnega čiščenja izpušnih plinov in ni okvara."
Google Translate: "After starting a cold engine, the engine speed increases and a whining sound is heard from the engine compartment. This happens due to additional exhaust gas cleaning and is not a malfunction.".

It is not happening at every start but is definitely noticeable.

UPDATE: I found it also here.
 
I wonder if the difference in our engines (North American vs Europe) is the Diesel Exhaust Fluid (DEF) system. I think you guys call it "AdBlue" . Does your cx5 use "AdBlue"?
 
I wonder if the difference in our engines (North American vs Europe) is the Diesel Exhaust Fluid (DEF) system. I think you guys call it "AdBlue" . Does your cx5 use "AdBlue"?
Hello, my cx5 does not use adblue. I actually found a thread on another forum that explains the reason for this apparently random behaviour. It has to do with the outside temperature. If the outside temperature is above a certain threshold then the engine revs up. If it's below it goes straight to idle.

Here it is, it's in German, but Google translate helps Beitrag im Thema 'Hohe Drehzahl beim Kaltstart (gelöst: das ist kein Mangel!)' Hohe Drehzahl beim Kaltstart (gelöst: das ist kein Mangel!)
 
I wonder if the difference in our engines (North American vs Europe) is the Diesel Exhaust Fluid (DEF) system. I think you guys call it "AdBlue" . Does your cx5 use "AdBlue"?
So your US CX-5 2.2L diesel doesn’t use AdBlue DEF? At least Anchorman’s 2019 CX-5 2.2L diesel in UK uses AdBlue.

Gas cap door observation

See post #18 for his comments.
 
Hello, my cx5 does not use adblue. I actually found a thread on another forum that explains the reason for this apparently random behaviour. It has to do with the outside temperature. If the outside temperature is above a certain threshold then the engine revs up. If it's below it goes straight to idle.

Here it is, it's in German, but Google translate helps Beitrag im Thema 'Hohe Drehzahl beim Kaltstart (gelöst: das ist kein Mangel!)' Hohe Drehzahl beim Kaltstart (gelöst: das ist kein Mangel!)
If you read the post #18 in that thread by Anchorman, he did mention the sometimes fast idle, 1550 rpm from his picture shown, on his 2019 2.2L diesel. It’s due to the use of new multi phase injectors for power increase. “Because the special injectors can get condensation inside them if the engine is started for short periods, it will go into a self flushing mode where it purges the fuel in the injectors with a fast idle. It is completely cancelled when a gear is selected so it doesn*t pull at the car but it does get questioned when owners see the message “Fast idle due to dirsel injector cleaning”.”
 
Nah, other way around. My USA model does have the DEF and seems like the older euro models do not.
According to Anchorman his 2018 CX-5 diesel doesn’t use AdBlue but his 2019 CX-5 diesel with some power increase does. Other than the added DEF cap next to the diesel cap, the exhaust tip has reduced to one to accommodate the DEF tank at the left-rear. Do you have only one exhaust tip to the right too?
 
Not the same thing, but my petrol fueled CX-5 does just that. If the outside temp is 10-15C-ish It starts and revs to 1800 RPM. But, if the temp is 0C-ish, or below, it starts and runs at 1000 to 1100 RPM. Your engine is likely normal
 
Back