What happens to the RPM after a cold start?
But cars nowadays have a “cold start device” that will raise the rpm after a cold start until the engine is warm. This will offset the “naturally lowered” cold start rpm and can range from not completely compensating the lowered rpm to overcompensating depending on the type of cold start device and on the programming of the cold start electronics.
Why does an engine run slower in a cold start?
To keep the engine running while cold, the ECU adds in extra fuel. On carburetor engines, they used a choke. The rich mixture requires ignition timing to be restarted. This causes the engine to make less power. The higher idle allows the engine to run while the air fuel mixture and timing are less than optimal.
Is it bad to warm up the engine at 600 rpm?
Warming up by idling (the 600 rpm idling) is not only bad for the environment, but also for the engine. It is generally recommended to warm up the engine at moderate rpm and power, i.e. by driving in a civilized fashion.
Why do idle RPMs go up and down?
The higher idle allows the engine to run while the air fuel mixture and timing are less than optimal. On the car with the idle that was going up and down, the ECU was likely trying to calibrate the inputs and output to get the idle where it needs to be.
Why does the starting RPM drop when it’s cold?
It is normal that the starting rpm is dropping when it’s cold. The battery is struggling a bit to deliver power needed to turn the starter. When it’s cold the engine shrinks a little and makes is harder to start. I will recommend you to start the engine and then let it run for a couple of minutes.
Warming up by idling (the 600 rpm idling) is not only bad for the environment, but also for the engine. It is generally recommended to warm up the engine at moderate rpm and power, i.e. by driving in a civilized fashion.
Can a car start when the engine is cold?
From a mechanical point of view, if the engine would be at the same settings as when warm, the cold engine would have lower rpm (and stall/not start), so: yes. But cars nowadays have a “cold start device” that will raise the rpm after a cold start until the engine is warm.
What happens when engine gets up to temp?
Truck runs great cold when it gets up to temp the power decreases greatly. new fuel pump, new fuel filter, new air filter has been hooked up to two different computers and it’s showing no codes at all. New muffler and dual pipes,the old ones were bad. im at a loss and so are my mechanics