It started with the engine stumbling during cold wheather conditions (40 to 50 degF) and once the engine warms up the stumbling stops. Now, if I do not start the truck once a day, I will have to turn the engine over 8 to 12 times before I will start. I lift the hood and I can smell fuel. This is no fuel leak. There is some dieselling that occurs once I let the key out of the start position. This is a chevy 1500 2 wd with a vortex 350 engine.
The vortec engine is fuel injected whether you have MPI or SFI or even TBI depending on the year sounds like you may have a faulty coolant temperature sensor. It should be located toward the front of the intake near the themostat houseing. It sends a signal to the computer to richen fuel mixture and also control the idle air control valve to idle the engine up some. If these parts malfunction, you will have the stumbling problem.
The diesling comes from carbon deposits that build up on the valves. The carbon glows red hot while the engine is running and when you shut the engine off the red hot deposits act like glow plugs in a diesel engine and ignite unburned fuel in the combustion chamber which is why the engine is still running when you shut it off. A bottle of fuel injection cleaner once a month should start to fix this problem if not the heads will need to be pulled off and a valve job done.
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Re: Engine turns over but wil not start
Sounds like a fuel pressure regulator or possible fuel pump next time it wont start on the first try turn the key on and off a few times and then try it. Also locate the fuel pressure regulator and remove the vacuum hose have some one turn the key on if it leaks out fuel the regulator is bad becarefull when doing this the system is under high pressure and can possibly soary gas in youre face.Also check the tune up most of these engines have lots of problems with distributor caps and rotors
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because the combustion inside the engine is going wrong the quantity of air getting inside is not the needed quantity maybe less than or more in cold will cause such problem once the engine warm up than the engine temperature is up you will not find this problem because the point of firing will be near
It's diesel. Diesel engines do not like cold, but that is normal. I am going to assume this engine has a start delay in cold weather to allow for Glow Plugs to warm up the cylinders before actually turning over the engine. I don't know about TDI's specifically, but I think a TDI Mech at your local Volkswagen dealer could confirm my assumption. They may call the parts something different, but the function will be the same. Sounds like normal operation for a diesel engine in cold weather...obviously, this would be why the engine always turns over immediately in warm weather...no need for the Glow Plugs to warm the cylinders. Best of luck resolving this problem.
a bad engine coolant temperature sensor will cause cold no start conditions.your coolant sensor main sensor during cold start condition because when engine coolant cold PCM will cause rich fuel mixture for cold start up when engine coolant and oxygen sensor warms up cause engine goo in close loop lean mixture.but coolant sensor is the main information sensor if bad it will cause many problems.
You will need a multipoint check on the engine.
start with the fuel, fuel filter, fuel pump, fuel injectors and the fuel lines. Fuel problems are heat dependant and wil show up in cold or warm condition. check calibration of pump.
Now check the ignition circuit of the engine. start with the plugs- now being new- check the HT wires, the HT coils, the triggers to the coils- the ignition system.
Also check the fault condition of the ECU.
Symptoms of a bad EGR valve are usually stumbling idle or the engine stalling when the car is warm (normal operating temperature). Find the EGR valve and locate the vacuum line attached to it. Start the engine cold and wait for it to warm up. When the engine starts to stumble, pull off the vacuum line. If the EGR is bad, the engine idle will stabilize and no longer stumble.
Is the car idling faster than it has in the past when cold? The car is designed to idle a little faster than normal during warm up, to warm the engine quicker, and to keep it running. The fuel/air mix richens, (more fuel in the mix than normal), during start up conditions, and then as the engine warms, it should idle down to normal. Have you allowed it to continue its fast idle to see if it idles back down? Your post indicates that you turn it off and re-start to prompt the car to idle down. You have electronic fuel injection. The system adjusts to the prevalaint conditions to give you the perfect mix regardless of the condition it is presented with. It gathers input from a series of sensors that detect engine temp, outside temp, humidity and air pressure, to deliver the mix it needs. Often, when the mix is off, it is a result of a faulty sensor. This can be detected by running a fault code diagnostic check. You can have this performed for free at most national parts chains such as advance or auto zone. Other factors can cause an improper mix, such as dirty or clogged injectors, and/or a dirty air filter. Good Luck! I hope that you find this to be very helpful!
Sounds like a cold start valve (which is actually an additional injector in the intake to assist in cold starting) If you can get it to your local prts store while the light is on they will read the codes for free and tell you what the car thinks is amiss.