Hello, I've read through tons of threads with similar issue as my trucks having but cant find an answer to my trucks problem.


It’s a 2009 F150 Lariat, 4x4 crew cab, 5.4 liter with 175,000KM's. Very recently has developed a random no start condition. It cranks every time but just wont start or run. When it is running there is no hesitation, sputtering, stalling or other problems. The crank no start problem occurs completely randomly. Sometimes it starts right up, and other times it just won’t and I often need to let it sit for while after not starting. It always cranks, never a dead key

This maybe coincidence, but the auto crank (where you just turn it and it cranks until it either starts or no start timer runs out) stops working. This only happens on the occasions it isn't going to start. Rarely it will autocrank but not start, and only after it doesn’t start does this happen, takes a longer key turn to get it running.
Today I went to grocery store, started right up. Left the store and it started right up. Drove to girlfriends house, started right up there. We got to lake where truck sat for about 2 hours, would not start. I tried for about 5 minutes, put key in, take key out, shift to neutral, back to park, etc etc. (swear under breath) tried again and finally started (including auto start key turn function)


Things I've done/checked so far;

Replaced the Crankshaft position sensor and connector, done last year as truck stalled and wouldn’t start, code said no signal and that sensor replacement worked fine (until very recently this issue began)

Fuel pressure is good, pre start and after it starts theres lots of pressure.

FPDM was just replaced (was told to try it, and it was relatively easy and cheap so it’s done)

All fuses checked, none blown.
Fuse 27 relocation kit installed (old fuse was fine though, no burning, melting etc but again, cheap and easy to rule out)

MAF cleaned (no codes)

There are NO CODES at all stored in ODB2 or when hooked up to FORSCAN using the advanced scanner.

There is no MIL or CEL ever.

The remote starter (aftermarket) was disconnected, still occurs without it wired in place.


I cannot just replicate the problem, took it to a repair shop, mechanic was confused as it started each time for them, it is completely random.

The truck runs great when driving. never stalls or bucks, it idles very smooth and gas mileage is still great, again NO CODES to say there's a problem. It seems more like no power to spark, or something like that as the fuel rail is pressurized and charged when keys on.


Hope someone can send some ideas or tests I've missed, perhaps things I should be checking and ways to check them?

Thank you

 

Perhaps check to see if there is spark?

 

Purge Valve, the happening after filling with gas and after it sits in the heat it is acting just like it is flooded. Just like I said in your other thread it might take a while for the code to come up.