Bernievarian
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- Jan 15, 2017
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Hi Guys,
I thought it's about time to post a reminder as winter is coming.
Diesel engines are very demanding at start time when the weather is cold, this is (partly) due to their ignition system. The ignition is not "commanded" by a spark like in petrol engines, but by the injection off fuel in the overheated air resulting from the compression stroke.
As the engine itself and the intake air are cold (specially in winter), the compressed air MIGHT not be warm enough to ignite the injected fuel and the engine will struggle to start, but eventually after a few more compression cycles (if the battery allows...).
This is why the glow-plugs are installed on diesel engine: they pre-heat the combustion chamber (or the air-flow, depending of design) so the end of compression temperature is high enough to start burning the injected fuel. If one or more glow-plug(s) fails, the corresponding cylinder will not fire-up and the engine will "run on 3 legs", or less, or even not start at all.
The other common issue in cold weather is the battery condition.
The battery is a chemical device and as such is more "active" as heat rises, so in cold weather it almost goes to hibernate like a bear. The trick here is to gently wake it up, like a sportman it needs to get warm(ish) before doing his effort.
On a diesel car this wake-up is done by the pre-heating circuit (if ok).
On a petrol engine this could be done by draining some current from the battery before running the starter motor: get in the car, turn ignition ON, switch the main lights on for 4 - 5 seconds, switch all OFF (lights, blower,demister) and start the engine. This will have initiated the chemical reaction in the battery and allow it to provide more instantaneous power.
Of course none of those will help if the battery is worn or the charging circuit is deffective !! As a rule of tumb, a battery showing signs of weakness as winter comes is PROBABLY on its way out; time to chek / replace ...
Hopefully this will help some to understand why the damn car doesn't start and maybe start their engine the right way ;-)
BRs, Bernie
If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)
I thought it's about time to post a reminder as winter is coming.
Diesel engines are very demanding at start time when the weather is cold, this is (partly) due to their ignition system. The ignition is not "commanded" by a spark like in petrol engines, but by the injection off fuel in the overheated air resulting from the compression stroke.
As the engine itself and the intake air are cold (specially in winter), the compressed air MIGHT not be warm enough to ignite the injected fuel and the engine will struggle to start, but eventually after a few more compression cycles (if the battery allows...).
This is why the glow-plugs are installed on diesel engine: they pre-heat the combustion chamber (or the air-flow, depending of design) so the end of compression temperature is high enough to start burning the injected fuel. If one or more glow-plug(s) fails, the corresponding cylinder will not fire-up and the engine will "run on 3 legs", or less, or even not start at all.
The other common issue in cold weather is the battery condition.
The battery is a chemical device and as such is more "active" as heat rises, so in cold weather it almost goes to hibernate like a bear. The trick here is to gently wake it up, like a sportman it needs to get warm(ish) before doing his effort.
On a diesel car this wake-up is done by the pre-heating circuit (if ok).
On a petrol engine this could be done by draining some current from the battery before running the starter motor: get in the car, turn ignition ON, switch the main lights on for 4 - 5 seconds, switch all OFF (lights, blower,demister) and start the engine. This will have initiated the chemical reaction in the battery and allow it to provide more instantaneous power.
Of course none of those will help if the battery is worn or the charging circuit is deffective !! As a rule of tumb, a battery showing signs of weakness as winter comes is PROBABLY on its way out; time to chek / replace ...
Hopefully this will help some to understand why the damn car doesn't start and maybe start their engine the right way ;-)
BRs, Bernie
If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)
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