I have a 2012 FX4 with a 5.0 L V8 today after spending some time at the lake I went to start it the engine cranks for about three seconds and then stops cranking cycle the key it cranks for three more seconds stop cranking the engine won’t fire I know about the fuse 27 issues and will be checking that in the morning but the fuse does not look burnt or blown to me just wondering if there are any other ideas of things I can check I cannot hear the fuel pump run

 

#8 relay under the hood is for the fuel pump and back near the spare tire on top of the left side of the crossmember is the Fuel Pump Driver.

 

Checked and swapped relay #8. Discounected teh fuel line at the rail, turned key on and got a real good stream of fuel.
Pulled one of the spark plug leads, adn dont seem to be getting any spark.
Im thinking it may be the crank sensor

 

Any update on this?

 

I have fuel pressure to the rail, but apparently no spark. My friends brother(mechanic) recommended the rank sensor. I have ordered one as no body had it in stock. Should be here Friday. I have also ordered a Forscan tool and downloaded the software, that will be here Friday as well.

The funny thing, this truck is not not throwing any codes according to my neighbors code reader. Except U00422- Which is a body module code, that I have read should have no effect on the engine running, I cleared that code.

 

So I down loaded and hooked up ForScan today. Ran the DTC function several codes
U0422
P1639
A bunch of others that seem to be related to the PCM not sending a communication signal

 

I had a similar issue. I was using a OBDlink WiFi OBD reader (one that I use for forscan) just to monitor some parameters in the Obdlink App. I noticed it was making the truck run rough and after turning it off it would crank but not fire. There was a bunch of error codes with the PCM and HVAC system, I had no HVAC button lights or function. I think I disconnected the battery for a while after clearing the codes to get it to start again. I may have uploaded the factory as built data to the BCM as well. Gave me a mini heart attack, thought I fried my modules.

It doesn't sound like you had anything plugged into the OBDII at the time but I would try an extended battery disconnect first.

 

Sounds like you should check your PCM wires, there's lots, and plug/unplug them several times. I think I'd do that with the battery unhooked.

 

crank position sensor replaced and she started right up

 

Im in the same boat right now. NO codes but all of sudden crank but no start nor want to start. I may need to look into this crank sensor?!

so again you didnt get a code for crank sensor...you just whittled it down to this?!

Thank you sir