I've been wondering what could be the cause of this. When truck is "cold" the crank time seems longer than expected. I've attached a video of first start in the morning and another video after about 4 hours later. I've also experienced the same longer crank when its been sitting for about 8 to 9 hours. Any idea of what could be the cause?

 

How many miles on it? When was last spark plug change? Have you ever cleaned the throttle body?

 

There can be a number of differing causes for the delay in firing off.
The starter is not one because, as you hear, it the turns over quite briskly.
A. Lack of sufficient fuel pressure/flow for any reason.
B, Ignition.
C. Temperature sensing fault.
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I have been chasing this for several years on my 5 L.
The suspicion is as follows.
1. The fuel tank is not bleeding "up" to atmospheric pressure causing the fuel pump to pull against that vacuum.
2. The cause may be due to an EVAP system fault that is not setting any code.
I picked up on the fault with my Scanner reporting an out of spec range condition in Mode 6 testing and kept ignoring it until now.
3. What I see by opening the fuel fill internal second valve to be sure the tank has no vacuum, priming the fuel system serval times seem to result in shorter crank times. That may support the thought pattern.
4. Remember during cold temps the fuel has to be richened up by the PCM for cold starting.
5. The fuel pressure min spec is greater than about 60 psi before cranking begins.
After the engine fires off, the fuel pressure rises upwards anywhere for 600 to 3000 psi as the low pressure system feeds fuel to the high pressure pump and pressure builds..
The work on this is yet to be completed until I clear the EVAP system fault I see, because at this point, it doesn't cause any Code or issue otherwise.
Warm ambient is no issue as starting is normal for crank time, no issue with the engine otherwise..
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My thoughts are the fuel tank gets heated from the warm air out of the engine bay and exhaust. The tank cools to a vacuum condition after parking long term, that remains for the next cold start and causes the pump delay in pulling sufficient fuel out of the tank.
I am hoping the EVAP fault will clear this because it causes extra crank time on the Battery when cranking is really needed and puts extra aging on the Battery life and higher required recharge current and recharge interval.
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You may have a different cause, but is the way I see my issue, at the present time, for you to consider.
Good lick.

 

Truck has about 78500miles, car fax stated it was done at a ford dealership at around 60800miles.
I cleaned the throttle body this past summer, really wasn't dirty at all.

 

I'll need to try this theory again, but I believe if I opened the driver door first and you hear the pump prime, it starts normally. Will report back on this.

 

Well it does seem to turn over less if door is open prior to initiating command start.

 

You ever figure out what was causing it?