Engine starts but then sputters and shuts off after 5 minutes (vehicle, spark plug)

[GarageLogic]

Originally Posted by Mighty_Pelican

Very interesting responses, thanks. I have half a tank of fuel.

I didn't include this in the original post but shortly before the engine stops running, the fuel gauge goes from half to zero. Every time.

That's probably just because the engine shuts off.

[NJGOAT]

Originally Posted by GarageLogic

That's probably just because the engine shuts off.

Well, he said shortly before. That part is what's leading me to an issue with the fuel pump itself and the associated electronics.

[TurcoLoco]

Originally Posted by GarageLogic

That's probably just because the engine shuts off.

I'd agree if it was dropping to zero shortly after the engine was shutting off, not before.

Originally Posted by NJGOAT

It would help if we knew the year, make and model of the vehicle. It can all be related and caused by the condensation freezing. It could also be an electronic issue related to the relays in the fuel pump assembly. The fact that it keeps starting and runs for a bit leads me to think it may not be the frozen issue, but that is certainly still on the list. It could just be that the fuel pump or ignition switch is going bad.

Those two, especially the fuel pump failing possibility was what I thought of first. Especially if the fuel gauge sensor is a part of the fuel pump assembly.

So doing what NJ goat mentioned, turning the ignition on, waiting couple of seconds then turning the ignition off a few times should presumably prime the fuel pump and build some pressure. Perhaps, checking the fuel line pressure is in order (it is very easy and you can rent the kit from Autozone, etc.)

Another thing I'd definitely do is to pop the hood up and watch/listen and observe what is happening when the engine dies.

[GarageLogic]

Gentlemen, I'm still holding out for moisture in the fuel system. That's my story, and I'm sticking to it!

I hope Mighty Pelican will soon return, and let us know exactly what he/she found.

[TurcoLoco]

Originally Posted by GarageLogic

Gentlemen, I'm still holding out for moisture in the fuel system. That's my story, and I'm sticking to it!

I hope Mighty Pelican will soon return, and let us know exactly what he/she found.

Believe me, I think you and NJGoat nailed it!

I mean even if fuel pump failed, some sort of a fuel contamination was likely the cause of it, especially since he mentioned:

I just got back from a trip that lasted about 50 days, my car was parked outside in the heart of the polar vortex.

So, quite possibly, he has multiple issues to deal with.

[Guitarmaan]

I had a similar problem recently and changing the spark plugs solved it.

The car would start ok and then shortly after the engine would quit. I wouldn't have suspected spark plugs because the engine started initially. But I took it to a garage and they changed the spark plugs.... no more engine stops.

[GarageLogic]

Originally Posted by TurcoLoco

Believe me, I think you and NJGoat nailed it!

I mean even if fuel pump failed, some sort of a fuel contamination was likely the cause of it, especially since he mentioned:

So, quite possibly, he has multiple issues to deal with.

Actually - seriously - I wouldn't be surprised if there is some condensation gathering on that little screen that is on the bottom of the fuel pump, right along the bottom of the tank. As enough moisture moves through it, it freezes, and starves out the pump.

And I truly hope that's what it is, because the fix is cheap and simple!

[RayinAK]

Originally Posted by GarageLogic

By the way, if you're using gasoline that contains 10% ethanol/alcohol, you basically have HEET in the fuel system. It should never freeze up.

Ethanol freezes, and that's why it's not used in Alaska. But Isoheet (the red color Heet) works better than the yellow-color bottle. Something else that freezes or jells is #2 diesel fuel at the pump, so during the winter months what is sold at the pump is $1 diesel (a #2 that has been blended to resist freezing).

[RayinAK]

Originally Posted by RayinAK

Ethanol freezes, and that's why it's not used in Alaska. But Isoheet (the red color Heet) works better than the yellow-color bottle. Something else that freezes or jells is #2 diesel fuel at the pump, so during the winter months what is sold at the pump is $1 diesel (a #2 that has been blended to resist freezing).

I apologize to garageLogic. He was correct about the very high freezing point of ethanol. But the reason why it's not used in Alaska is because the gasoline/ethanol blends create engine start problems, something to do with vaporization (don't know the technical stuff). Anyway, while the ethanol/gasoline blend may not readily freeze, moisture from air getting in the tank as the level of gasoline in the tank drops, does freeze. See…moisture does not mix with the gasoline/ethanol mix past the amount of ethanol present in the blend, although some of the mixture will be absorbed by the ethanol depending on temperature. Moisture past that point flow toward the bottom of the tank, and eventually freeze in the fuel line and other components.

But the ethanol and other liquids (Heet, Isoheet, etc.) probably is pure enough to absorb more of the mixture in the tank, and that's why Heet products are so widely used in Alaska.

[RayinAK]

I meant to say, " absorb more of the moisture remaining in the tank."