Since this issue confuses me, I know the ford dealer has no chance, but the forums always seems to have an answer. So here's the issue. 2016 F150 5.0L XLT SCrew.

Truck has an extended crank of almost 5 seconds and will keep cranking when letting off the key until engine starts (sometimes barely starting), but this issue only occurs in a very specific timeframe, if the truck has been driven between 2 to 5 hours before.

Normal first start fires up fine with a second or to of cranking and fine if it's been sitting for a few days or over 5+ hours. Also, if I drive to the store, take like an hour and go to leave, starts just fine. Only happens between 2-5 hours after being previously driven. No unburnt gas smell and no leaks of any kind. Any assistance would be greatly appreciated.

Thanks.

 

Same thing happened to me. I drove myself crazy thinking the starter was going out. It's crazy to me that I'd be on a 2 hour drive, stop to get gas and the truck wouldn't start. I'd have to let it sit and cool off before it would start. After sitting all night, no problem it would start right up!

Turns out the battery was dying. The complete opposite of every other battery that's died in a car before. I even had the battery tested and it tested good.

I replaced the battery and it's been good since.

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I will second I27's call of a dying battery. Sounds very much like how my truck behaved when the original battery was on its way out.

 

I had the exact same, but only happened on hot days. Cycling the key for a few seconds first in the hot condition would make it start the same as cold crank.

Replaced fuel pump, never done it again. 2016 5.0 for me.

 

I've noticed this also. My truck can sit for 3 days and fire right up. Zero issues. I've noticed it having a long crank if I go out mid day when it's hot outside. I figured it was something to do with a pressure release system. I've got almost 90k and maintenance on point. Just did the spark plugs a month ago and tossed in a new battery. This was happening before that. I plan on taking it in and having them look it over one day. No trouble codes or anything. I'm leaning towards a fuel pump, but I've been told if it was a fuel pump I would have other issues not just a random long crank. I would see possible stalling issues, mpg issues etc and I have none of those.

 

I had zero other symptoms, never checked any codes, never had any lights and it was the fuel pump. Reason I thought that was the heat of sitting and fuel rails would push fuel past whatever check valve was in the pump so it had to prime before it started. I figured that’s why cycling the key (letting fuel pump run) would make it not happen in similar hot conditions. At the tail end I had one long crank in cold weather and swapped the pump.

 

Well, funny thing is I have a brand new fuel pump I never installed from another f150. ill have it looked at, if they can't confirm what it is 100% I'll just have it tossed in and see what happens.

 

Keep us posted! Hope that solves it!

 

I replaced my fuel pump unit and module above spare tire due to a faulty sending unit and pump failure to energize. That’s when I noticed the extended start when hot issue. After its hot, I have to turn key to energize the pump for a few moments before attempting to start. Behaves like its vapor locked.
Not a diesel so prime shouldn’t be an issue? Footnote: First aftermarket pump assy was miswired at the connector…made in…you guessed it…China.

update: since the stating issues didn’t occur until after I changed the fuelpump, I’ll install another new pump and check all the fittings (in reverse order). BTW… I found the best way to access the pump is to remove the bed bolts and rear bumper pcs and simply slide it back onto the rear tire with bed tilted upward. Way easier than dropping the tank in the driveway.

 

I had this. Mine's an 18 5.0. Replaced the battery and it ran better for some time. Then had issues cranking again, found it was my starter. Bad grounding strap that's on the starter. It was corroded, green, and brittle to the touch. Not saying it may be the same for all of you, but it's something to look at. Maybe it will help someone.