Replaced fuel rail sensor, won't start.

[ellev8or]

2005 Mountaineer
136000 miles
4.0 FlexFuel
AWD

Greetings to all!

Engine threw a P0193 code, fuel rail sensor. Carefully replaced the sensor and put everything back together. Now it won't start. What can be the issue?

Thank you.

[shorod]

You didn't happen to pull the fuel pump fuse or disable the inertia switch to de-pressurize the system prior to replacing the pressure sensor, did you? If so, did you reinstall the fuse or reset the inertia switch?

Have you confirmed whether or not you have fuel pressure now?

-Rod

[ellev8or]

Shorod

Thank you so much sir for responding.

I figured out what you've replied with. I did remove the fuel pump relay for the reasons you stated. After putting everything back together and it would crank but wouldn't start. I'd never heard of an inertia switch, hell, I thought it was the reset button for when you change the oil. But I got it started with pressing the switch.

After a couple of days driving, today it stalled out. I went to start it after a few errands and it crank up, started, but immediately died. What can be wrong now?

Thanks again.

[shorod]

Did it start fine after the stall? Did you replace the fuel filter after you replaced the fuel pressure sensor? I guess I'm not positive that your 2005 has a user-replaceable fuel filter without changing the fuel pump though...

I'd also suspect possibly a weak battery (they cause strange behavior when they are old, usually around 3 years old). If the battery is brand new and known to be good, then you might consider a crankshaft position sensor. There are all sorts of things that we could recommend, but of most help will be to determine if you have correct fuel pressure and whether or not you have spark when the vehicle fails to start.

-Rod