WHY DOES MY ENGINE OUT WHEN ITS COLD - 2002 Chevrolet TrailBlazer

Its probably a problem with the water temperature sensor. Also do not rev a cold engine. The engine has a "cold start sequence" which is similar to a choke. When the engine gives a cold signal, the fuel mix is made richer and the timing is changed until the engine warms.

Let the engine warm at the preset factory settings. Sometimes the O2 sensors will cancel the cold start sequence before the water is warm. Racing the engine will warm the O2 sensors too quickly.

Hi,
This sounds like you have a faulty cold start sensor which helps the engine with more fuel when it is cold...
Have this checked.
Thanks
Jason

Reason 1 - Gasoline, like any other liquid, evaporates less when it is cold.You have seen this -- if you pour water onto a hot sidewalk it will evaporate a lot faster than it will from a cooler place like a shady sidewalk. When it gets really cold, gasoline evaporates slowly so it is harder to burn it (the gasoline must be vaporized to burn). Sometimes you will see people spray ether into their engines in cold weather to help them start -- ether evaporates better than gasoline in cold weather.

Reason 2 - Oil gets a lot thicker in cold weather. You probably know that cold pancake syrup or honey from the refrigator is a lot thicker than hot syrup or honey. Oil does the same thing. So when you try to start a cold engine, the engine has to push around the cold, gooey oil and that makes it harder for the engine to spin. In really cold places people must use synthetic motor oils because these oils stay liquid in cold temperatures.

Re ason 3 - Batteries have problems in cold weather, too. A battery is a can full of chemicals that produce electrons The chemical reactions inside of batteries take place more slowly when the battery is cold, so the battery produces fewer electrons. The starter motor therefore has less energy to work with when it tries to start the engine, and this causes the engine to crank slowly.

All three of these problems can make it impossible to start an engine in really cold weather. People either keep their cars in heated garages or use "block heaters" to get around these problems. A block heater is a little electric heater that you plug into the wall to keep the engine warm.
i hope it was convince answers

I'm assuming the engine cranks with the starter but does not start and run.

check the operation of the cold start injector. This is a separate fuel injector that injects fuel into the intake manifold to help richen up the mixture for cold starts. It operates on a timer that is linked to a sensor that measures engine coolant temperature. Once warm or the timer runs out, the cold start injector is turned off. Other things to check:

Fuel pressure too high (floods engine through cold start injector), engine coolant temp sensor or intake air temp sensor is stuck at full hot (doesn't allow enough fuel for cold starts), fuel injectors are leaking (floods engine with fuel).

hello wyatt...... Is your jag.built with a carburetor or fuel injected?
Carb, your choke is not set to close when cold, and should be set. When set, it also sets a cam that keeps the engine running fast. Then when warm, you hit the pedal and the cam moves, and the engine speed goes to normal. Unless the choke is set, the engine cannot keep running, as it tries to run on cold gas and it can't run good on cold gas. It needs more gas, therefore, and the choke makes more gas go into the engine.

Fuel Injected, the computer should adjust the amount of gas your car is getting when cold. If not, the coolant sensor might be bad.
The coolant sensor senses the cold engine and tells the computer to add more gas. Once the engine is warm, the coolant sensor tells the computer to put the gas to normal.
So, if the sensor is not working, the engine will try to run normal, and if cold, it can't. Joe Thanks for choosing Fixya!

Check the CHT sensor .Could be telling the ecu that the engine is warm and not cold.
Let me know how it goes.

mcdevito75 here, Sounds like a faulty cold start valve / sensor. Have the shop check out the cold start system of your engine.

could be a cold start issue. there is a water temp sensor near the thermostat. when you start your engine first for the day it will show the engine to be cold and therefore the computer will do a 'cold start', meaning using more fuel. but this should throw a computer code. if you are not getting any codes from the computer then check for a vacuum leak. like the EGR vacuum line for starters. the egr should be closed when the engine is cold and open as the engine warms up.