Engine swing but refuses to start

Question edited for clarity.
Question moved to model category.

Check for Diagnostic Trouble Codes.
Reset Security and Engine Immobilizer.

https://www.google.com/search?q=Daewoo+Lanos+reset+security

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i tried to decode this
"and doesn't start it's not the fuel because I checked and even put in carb it should take when swinging (cranking)
"
I guess he meant sprayed test fuel to carb air horn, fails?
the cam belt is bad,(slipped) and fully expected.
and your adding fuel test is ON THE MARK, proves
engine or spark dead.(mostly)

What year is you Polo? If you are in any doubt about the fuel filter change it anyway! They are usually cheap to buy.
When was the vehicle last given a full service? Oil, Air and fuel filters can cause bigger problems that you would expect. Old spark plug can do the same.
I'll need a bit more information to help. When you drive it what exactly does it do? Is it low on power? Does it struggle when you accelerate hard? Does it stall at junctions? Does it idle unevenly? Use the comment button below and I'll try to help you more.
Fuel pumps generally last a long time and only fail on very high mileage engines. The only times they fail sooner is if it have not been used properly. Running a vehicle constantly with a nearly empty fuel tank causes the pump to overheat and wear out faster.
Most 4 cylinder engines use the firing order 1,3,4,2. Number 1 cylinder is the one nearest the belts and pulleys on the end of the engine.

check the basics first. Fuel pressure - there is a shrader (sp?) valve on the fuel rail on the engine where you can check that. Check if there is spark - pull on of the coils and put in a spark plug and crank. It can also be the ignition switch but check the two things above and then you will know where to look for the problem

Please define "fire power". Is this just the power from the battery swinging the engine, or did you check if there is a healthy spark on the plug wires? If an engine dies without warning, the chances are very good it is the crank angle sensor in which case there will not be any spark on the wires even though the starter will swing the engine quite lustily without starting.

well could be no fuel pressure or pump in tank stuck,try rapping on bottom of tank with a mallet while someone cranks it over if it starts get ready to change pump out in tank
one other thing to check look around and see if someone might have bumped into your car overnight,you may need to reset your inertia switch on inside of truck check your manuel for location

That is the engine oil cooler. There is a 'O' ring between it and the oil filter mount. They harden and crack.

Ask your dealer for the large Oil Cooler 'O' Ring.

Remove oil filter. Remove exposed pipe nut holding oil cooler to housing. If nessacary, drain coolant so you can disconnect coolant hoses from cooler or catch coolant as hoses disconnected. Swing oil cooler away and remove old 'O' ring.

Place new 'O' ring with grease on oil cooler it to hold it in place and reassemble. Tighten oil filter pipe nut to around 18 ft lbs .

Refit oil filter. Refit coolant hoses and top of oil and coolant.
Run engine to check for leaks and allow to cool. Top of coolant to COLD level if required.

You will need hose clamp pliers and wrench for oil cooler pipe nut. Pliers can be obtained from most parts stores.

Make sure all the air is bled out of the cooling system they are bad about air being traped.There should be a bleed around the thermastat housing crack it open let engine run until normal temp and steady flow of coolant then tighten up and top off with coolant.

Check for a leak in the air intake. The reason why I said this is because a leaking air intake causes a low idle condition if its after the MAF sensor. If the leak is bad enough the car wont even start. Some cars equiped with MAP sensor that has malfunctioned can also cause a no start condition.

It is your timing belt. Will set you back about $350.