It's a 2001 f250 Superduty 7.3 with 252k miles. I just bought this truck 7k miles ago up until about 250 miles ago it was perfect not a single issue. Now when I start it at ambient temperatures and the engine hasn't been warmed up it starts hard takes 10+ cranks. This morning when I went to start it took like 15 cranks and at least 3 of them were like the truck was on it's last leg right at the last couple of cranks then it started like nothing was wrong. After the engine warms up the issue goes away, but once it cools back down to ambient temperatures the issue comes back. When I bought the truck it has just had injector cup and injector o-rings changed so 7k miles ago at 247k. I also just replaced the ipr valve less than 100 miles ago. I also changed my exhaust which was stock downpipe to a 5in all the way back to a 4in downpipe and all the way back about 750 miles ago. Any idea what could be causing this? No codes, no leaks, no nothing. It runs perfectly fine once it's started but starting is the issue. Ive searched multiple other forums and posts and no one really has a similar issue to me and no one has really said a fix for it. I live in Texas and I start it in 80 to 110 degree temperatures. I got the truck in February and it was 20 degrees outside it started in like 2 or 3 cranks couldn't even tell it was cold out.

 

What brand of IPR you buy? Although that's not your problem it's better to have OEM sensor installed and keep the old ones as spares.

Your problem sounds like it could be bad injectors.

 

I bought an OEM Motorcraft IPR Valve. I read post and their reviews of aftermarket IPR Valves and instantly after reading reviews said I'm only buying Motorcraft.

I really hope it's not injectors, wouldn't that throw a code I feel like that would be something that is monitored I'm new to the 7.3 so I'm not sure just asking questions. I sure hope it's not injectors.

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Are the batteries and starter in good shape...it's rolling over quick? Can you run a buzz test on the injectors when it's not wanting to start? Is it throwing any smoke out the tailpipe when trying to start, and if so what color is it?

 

Have you checked your oil level?
Low oil, as in not reading on the dipstick will cause similiar hard start problems and if it's too low it won't start at all.

 

My first thought was battery condition or cranking speed as well.

How about battery terminals condition? In decent weather they can start on only one battery but just not be happy about it. Seen it a couple times actually.
One time I went to replace batteries and noticed one terminal wasn’t as good as it should be while performing the swap. It didn’t need batteries after all.

 

We were going out of town for a couple days and taking the wife's Ex that goes in the garage. My F350 sits in the driveway under the shade of a large oak tree. So I decided I'd just pull a battery out so the truck stays put. I thought...well, just for fun lets see how these a little over a year battery combined with the 6.7L starter will do on one battery before I yank both. To my surprise it never missed a beat, rolled over a couple times fast, and fired right up...so I yanked the other one...

 

Does your tachometer move when you try to crank it. If not it's a good sign you have a bad cam position sensor. If you're cranking and it's not moving then moves before it starts I'd check that immediately.

 

Im having a similar issue with my 2000 F350. Glow plugs are doing their job. Havent had any issues until our temps dropped. (its -12 now!). Just watched a video on the low pressure oil pump, seems to fit my symptoms perfectly. Check it out... My mileage is 291k.

 

After the truck sits a while and cools down pull the allen head plug on top of the HPO reservoir. Oil should be roughly an inch below the top. If it drains down the HPOP must refill that volume before oil is available to fire the injectors.

 

if oil pressure gauge takes a while to engage, you might have low oil, cracked pickup tube or weak LPOP or faulty drain back valve on HPOP

Mine does it once in a while if it let it sit for a month or longer. I have checked the HPOP and its always full.

 

CLASSIC symptoms of a failed glow plug system. I'm guessing the original poster figured it out and never checked back in on this one. Only two posts and they are in this thread.