Automotive What does the smoke color means in diesel car and petrol car?

[ruxy667]

Hi there, i just started to learn mechanic about few years ago and I wanted to know about car smoke color,

What does the smoke color means in disel car and petrol car, Black,Blue,Grey,White smoke color?

 

[256bits]

Have you tried 'googling' the question about exhaust smoke.
Could be some info there to flush out.

PS
Hi

 

[ruxy667]

Have you tried 'googling' the question about exhaust smoke.
Could be some info there to flush out.

PS
Hi

Yes I did but not clear

 

[Baluncore]

Welcome to PF.

Petrol Black, running rich, air filter blocked or carburettor faulty.
Petrol Blue, worn engine burning lubricating oil.
Petrol Grey, lean, insufficient fuel, or too much air, also check engine timing.
Petrol White, burning brake fluid sucked into manifold by faulty vacuum brake booster.

Diesel Black, partial combustion, blocked air filter. Too much fuel delivered to injectors, or injectors dribbling, not spraying, may be due to blocked fuel filter.
Diesel Blue, worn engine burning oil.
Diesel Grey, rare, turbo bearings maybe.
Diesel White, unburnt fuel, when failing to start in cold weather, or with poor compression.

 

[Lnewqban]

Welcome!
Consider also that right after start up, when a healthy engine is cold, visible water vapor, and even water, could emanate from the exhaust pipe.

 

[jack action]

Petrol White, burning brake fluid sucked into manifold by faulty vacuum brake booster.

Or burning coolant fluid because of a leaky head or manifold gasket, or a cracked cylinder head or engine block.

 

[berkeman]

And by strange coincidence, this popped up in my Facebook feed today:

https://www.facebook.com/MechanicalEngineering1234

 

[Baluncore]

Visible smoke indicates a problem, or a transient startup condition. Smoke colour alone cannot be relied upon, it is just another technique, used to confirm or confuse the diagnosis of a problem.

These days, new diesel engines perform more like petrol engines, while new petrol engines have injection issues, more like diesels. The problems are converging, as ICE technology struggles to improve, in a losing battle against EVs.

 

[Rive]

Even a perfectly good car will 'smoke' white - in a weather cold enough.

But in general, any smoke is just about 'trouble' these days.

 

[Baluncore]

But in general, any smoke is just about 'trouble' these days.

And, with electric vehicles, even more so.

 

[Nik_2213]

Also, what about catalytic convertors ? Until they get up to optimal temperature, they're going to be passing 'stuff'.

And, {cough} diesel engines with hacked 'engine controller', trading performance plus fumes for economy ?

Oh, and is the diesel's 'AdBlue' tank in need of re-fill ??