Not the first complaint about this condition ...
2.7L towing and stalls.

I wonder if it's fuel evap related? What we'd all previously thought of as "vapor lock".

I don't own one of these, so I don't have the ability to easily look over the fuel line route.

I would recommend tracing the fuel lines from stem to stern and really look closely. Perhaps after towing (high heat from a very power-dense engine package) the heat in some situations is enough to vaporize the fuel temporarily in the line somewhere?

 

That is a very good point.

 

I think you are on to something... The engine was working very hard, the fuel level low (fuel pump cooled by the gas in the tank). Going from 75MPH with a load to idling at the gas station would surely set up an abnormal condition.

I don't buy that it was out of gas, close but not out!

That was the only glitch in the 20,000 miles on the truck. I am still amazed at how such a tiny engine could have so much power!

 

The conditions described by the OP here and the other recent thread have me thinking it's a form of vapor lock.


- Low fuel level contributes to less cooling of the fuel; less heat dissipation, because essentially the tank is the cooling area and less fuel means less mass to throw absorb heat energy. ( more gas is a greater thermal mass to alter temp; like the difference between hot water in a cup versus hot water in a bath tub).
- High towing loads contributes to higher "near-the-engine" heat from an already power-dense engine package. Any fuel line that is close to heat sources like the turbos and heads will get an extra helping of heat in high-power-demand use. And it is entirely possible that heat is taking a unique path in regard to airflow; the fuel line may not have to be "near" the turbo, but even the exhaust manifold or down pipe? Anywhere the fuel line travels needs to be assessed for heat sources nearby.
- low vehicle speeds means less cooling airflow in the general engine bay overall; the entire system now has a more difficult time rejecting heat to the atmosphere, because the thermal cooling rate is diminished with lower air-flow transfer

All these may be contributing to a form of vapor lock. It may be that all three must be present to contribute to the stall? Any one or two may not be enough?


My 2006 Dmax has an OEM fuel cooler for the diesel return line; it is quite literally a small radiator that cools the fuel just before it returns to the tank. I wonder if something like this would be helpful on the 2.7L trucks? Actually, I would say put it on the supply side; cool the fuel after the pump but before the engine. However, that may or may not be enough heat dissipation to matter. I also suggest this concern may be a reason to add some insulation wrap around the fuel lines in the tight areas near the engine. Again - I don't own one of these trucks, so I cannot comment as to where it might be prudent to do so.

 

I haven't pushed the fuel tank on my new f150, but I can attest that any modern vehicle/ford will not run out of fuel. On my previous truck, If my fuel level was any where near 5gal or less, the truck would immediately enter limp mode. What that meant was that the vehicle would go no faster than 20mph, the info display warnings that ones fuel level is low. It just won't let you run out of gas. Now maybe my old 2006 F250 6.0 was different, but I would bet that technology exists today. Low fuel should not cause the vehicle to stall, only reduced power.

JMHO

 

Was there a solution to the issue? I have a 2018 2.7 and it's doing the same thing. Towed our trailer to Florida last week and it would stall coming off of a exit. Sometimes it would do it after putting fuel in it too. Never below a quarter tank. It's going to the dealership Friday just wondering if there was a fix.

 

There's a lot of us with this problem. Ford won't admit it. Yet anyway. Happened numerous times with my 2016 2.7 pulling 5000# at 65 mph. No codes. NO fix, says Ford.