Why do carburated engines need to be "warmed up" and fuel injected engines do not?

Answer 1

Actually, some do. The answer lies in how much distance is between the fuel delivery system and the cylinder. Gas sticks to the cold metal intake manifold when it's cold. Port fuelies don't have all that metal between the injector and the cylinder whereas throttle body and carburettered engines have long intake passageways for the fuel to have to negotiate. When the metal gets warm, the gas vaporizes and goes all the way to the cylinders without sticking to the intake passages. Hope this helps.

Answer 2

Because cold engines need an enriched fuel to air ratio. Carbs' have a choke to manually take care of this. Onboard computer(s) assume the responsiblity of the fuel mixture. The injected engine idles faster when first started while cold. On the same note, carburated engines run faster ( idle at faster rpms ) when the choke is active. An 'automatic' choke has no manual control as opposed to the older autos with a 'choke' control inside the car and it has to be used unless the engine is still very warm to hot when starting. But like some of the other answers 'here', I think ALL engines should be warmed up before driving. The reason being is the engine will use more gas until the computer controlled devices start adjusting your fuel to air ratio, or a carb with an automatic choke preforms the same task.

Answer 3

If the carb and choke are adjusted right, there is no need to "warm up" the engine before driving. Today, most people don't know how to set a carb and choke. It's getting to be a lost art. Any car engine will get to normal operating temperature faster when driving than when sitting and idling.

Answer 4

all engines should be warmed up a little bit... just to help the oil circulate before you drive.

But i believe what your referring to is because the older carberated engines had a choke, (either manual or an automatic choke) where they would run rather undesireably until the engine warmed up sufficiently enough to relaese the choke. newer fuel injected vehicles have a more improved means of regulating the air flow to make it less noticable, although they do essentially the same thing

Answer 5

carbs have chokes
on fuel injection cars the computer richins the fuel mixture till the coolant warms up they both work the same
if your carburated car runs poor until its warm have the choke adjusted

Answer 6

Carbonated engines need warmed up in order to obtain proper operation of the components which are often made of dis-similar metals, and "warming up" allows even expansion. You should still warm up a FI engine, too.

Answer 7

It's the choke in the older cars. The engine must heat up. There is a coil on the manifold that opens up when it gets hot and cxloses when it gets cold. On the newer one the computer tells the computer when to open and when to close.

Answer 8

the modern fuel injected engines are regulated by an on board computer.most carbonated engines are not

Answer 9

Because they are based on contraction and expansion of gaseous hydrocarbons. Warming by heaters expands the gas in a limited space so it can be converted to motive power.