GEN 2 Engine starts and stops right away

[GordoJay]

The truck says my average MPG is around 13.

Gen 1? I'm getting 18.1 combined.

 

[CoronaRaptor]

My take on this, and I freely admit my take is nothing but a guess. To me it sounds like you were down to less than 10 gallons in the truck when you parked it. It saying you had 98 miles DTE on parking, what is your average MPG? For me 98 miles DTE would be in on the order of 7 or 8 gallons left under average conditions, maybe as low as 6 gallons left, generally not as much as 10 left. And you parked it on a hill facing down.

Both of the Raptor tanks, the 26 G and the 36 G, are long, narrow, tanks. The 36 gallon tank is over 6 feet long and only about 20 inches wide. The fuel pickups for both sized gas tanks are behind the center point, i.e. closer to the back than the front. Both tanks have a shallow well or depression in the area under and around the fuel pump and pickup. This well should keep fuel centered around the pump with the vehicle in motion and sloshing, even with a nose up or nose down attitude.

None of the below images are mine, I grabbed them off the web. I did add the lines and the angles.

These are the two tanks, the 36 gallon tank is the one in the back. The left side of the image is vehicle forward, the right side is vehicle back. The white'ish round section on top of each tank is the top of the fuel pump / gauge / pickup.


Below is the tank with a notional fuel level in it, call it a bit less than a quarter tank. You can see that the fuel pump is the lowest part in the system, with the bottom everywhere else sloping towards it.


Now I have rotated the fuel tanks 6 degrees vehicle nose down, leaving the red lines alone. The fuel pump well is no longer the lowest part of the system. The "nose" of the tank is significantly lower than the fuel pump, and the fuel has all shifted towards the front, away from the pump


To me it looks like the system is biased towards the rear. I mean if the fuel shifts rear wards the system continues to pick the fuel up well and the shape of the tanks minimize bunching to the rear. This makes sense to me. Under acceleration or going up a hill is the worst possible time for fuel starvation so you design to reduce that risk.

Ideally, of course, you would cover all bases and have no "bad" conditions, but real world engineering is managing those risk with realistic solutions that fit the mechanical requirements of the system. You fit it where you can and make it work the best you can in that location.

I see the same issue, but reversed, filling the tank as draining it. I have noted that I can put a little more fuel in the tank if the vehicle is slightly nose down than I can if the vehicle is slightly nose up.

T!

Awesome presentation 10/10 , great information

 

[OriginalToken]

Gen 1? I'm getting 18.1 combined.

It is all in how you drive it and under what conditions. I have gotten 18+ combined for several extended periods. On road trips with mostly highway miles I have gotten high 19's, even the occasional 20+ for a tank. However, when I drive it like I enjoy I get more like 14 or so, and have gotten something like just under 11 for an entire tank combined. Let alone off road, then seeing extended periods of 5 or 6 is easy.

Right now my Trip 2, which was last reset at the last oil change 2000+ miles ago, is showing 13.9 MPG. But I do like the feeling of the truck wide open a lot

T!

 

[GordoJay]

You need to buy something fast.

 

[CoronaRaptor]

Gen 1? I'm getting 18.1 combined.

I can get 20mpg in my gen1 on the hwy if i drive 50 mph on a flat surface

 

[mbRAPTOR57]

Pulled out of my driveway.. drove half way down the street and OUT. Started it back up and OUT again and again. Engine would stall immediately after starting. Pushed my 2018 w/ 40K miles back in front of my house.. did some googling and found this thread. Thanks to "Performance Blue" tried pulling the auto stop/start connector and there ya go.. bob's yer uncle. Worked!!

 

[grim_dep]

THANK YOU FOR THIS THREAD!!! I showed 74 miles until empty (1/4 tank), parked nose down showing 10 degrees. Truck would start and immediately die. Coasted her down to flat ground and she started right up! THANK YOU AGAIN!!!

 

[Old-Raptor-guy]

Most trucks fuel systems are designed this way.

Per the picture presentation a page back (excellent by the way)

In my mind there is a reason the pump is biased towards the rear.

As some have said, we go to far off places with no fuel stations in sight. I can coast down hil and/or it takes very little fuel to keep the engine running.

But going up hill, that is when fuel pressure/volume needs to be maintained. The pump being to the rear and the fuel flowing to the rear climbing a hill (especially when low on fuel) seems like the best option available.