Looks like cold weather is back. All last winter, I had trouble starting my Explorer whenever the temp dropped below 40-deg. All summer long, everything was fine. Now that it's cold again, it takes several cranks before the truck starts. Last year, I had the battery replaced, the fuel pump replaced, and swapped out multiple relays. This cost hundreds of dollars and it didn't fix the problem. There is no water in the lines, there is no ice the gas tank. I can't find any service bulletins addressing the problem. I see people have been experiencing this problem for years and it seems to occur between 50K and 75K miles on the vehicle. Once the vehicle starts, it is fine. Let the engine go cold again, and it's hard to start again. The colder the weather, the longer it takes for the engine to start, but it eventually does....everytime. Can anyone tell me if they have experienced this problem and know what fixed it? Let me repeat....it's not the battery or the fuel pump.
Thanks in advance.

 

Before determining that the fuel pump is not the issue, you would need to take fuel pressure readings at the fuel rail. Do you know if the fuel filter was replaced at the same time as the pump?

Does the fuel economy get worse in the cold weather too? Do you have a scan tool that you can use to monitor the intake air temperature reading and the Engine Coolant Temperature sensor reading? Once the engine starts does it idle fine, or is the idle unstable or rough?

-Rod

 

Yes, sorry, the fuel filter was replaced when the fuel pump was replaced.
The fuel economy stays about the same all the time. Approx 18 MPG.
I do not have a scan tool. Afraid I'm not advanced enough to know what that is, but always willing to learn.
Once the engine starts, everything is fine. It never idles rough or stalls. It simply takes several cranks to get it to turn over. The colder the outside temp, the more cranks. Above about 40 deg, starts fine everytime.
I'm just baffled and tired of laying out money. I've read plenty of threads about this same problem but no one seems to have posted whether they solved it and what it was. I will post the fix if we can figure it out.

 

I'm leaning toward either the Intake Air Temperature (IAT) sensor or the Engine Coolant Temperature (ECT) sensor. I would expect the fuel economy to be effected if either of these were the issue. A scan tool with datastream mode would help identify if either of these were the likely issue.

One other consideration is the age of the condition of the spark plugs and the age of the battery. Spark plugs with a large gap can certainly impact starting. Also, an old battery, even if it load tests fine, can cause the PCM to do some odd things on newer vehicles.

-Rod

 

Take it to Auto Zone or such and get a free scan for codes. I also suspect the sensors mentioned. When working properly they set the fuel injection richness similar to how a choke works on carbed engines. No choke, no start....in cold weather.

 

I thought about taking it there, but once the vehicle starts, everything is fine. If I pull into Auto Zone after driving it there, it will start right up. Will the scan still produce failure codes on a normal start? Do you see my dilemma? Almost seems like I need to have the scan tool at my house to use on a cold start. Maybe I'll need to wait for a cold day, drive it to Auto Zone, and then wait a couple of hours for the engine to go cold again. Thoughts?

 

If there are hard codes or pending codes they will be available with a scan tool, even if the vehicle is starting and running fine. In fact, the engine doesn't even need to be running to access the codes.

But if you want to see how sensors are behaving and what readings they have when the engine is cold you would need to have the scan tool connected and in datastream mode when starting the engine.

-Rod