Mazda 6 2.5 - Cranks But Does Not Start Up

[Arrods]

Happened few years ago and RAC man floored throttle and engine fired. Happened this morning (have had car new since 2009) and restarted successfully by flooring throttle. As before car now running OK. I seem to recall RAC man saying this can sometimes happen if you start and switch off engine momentarily (which I'd done).

Any ideas what might have caused this?

[bhg481]

If you only run a cold engine for a short time the coolant will not have circulated due to the thermostat being closed. This means that the cylinder head will be hot, compared to the rest of the engine, and the sensors which control the fuel/air mixture may be confused and make starting difficult.
Just a suggestion and happy to be corrected by anyone more knowledgeable than me.

[10ClarionSt]

Flooring the throttle will clear any excess fuel on the spark plugs. You have to hold the accelerator fully down for about 10 - 20 seconds to allow air to flow in, instead of fuel. This allows any excess fuel to evaporate and should allow the engine to fire up.

[Arrods]

Thanks both for your suggestions. The odd thing was that I ran and restarted the engine for a short time, put the car in the garage and it was only the next morning that it wouldn't start. It could be a sensor thing as I read something yesterday about these affecting starting, though, as I've said, this has only happened twice in 10 years. At least I know now how to resolve the issue if it happens again! Thanks again.

[10ClarionSt]

Just another thing. If you do have to hold the throttle down, as above, keep it all the way down when firing the engine up, until it starts up, then ease off once it's started. This will definitely burn away any excess fuel. This is for petrol engines only. Not diesel.