I've had some long crank time of about 3-5 seconds since this cooler weather has started. I'm in Alabama and the coldest its been is 37. I've plugged it up a couple of nights and the next morning it fires right up! When I don't plug it up is when I get the longer crank times, but if I let the glow plugs cycle twice the truck fires up great! I have a SB intake and turbo back straight pipe exhaust so I know its getting tons on air. Could this be a back pressure issue or something else?

 

I doubt it's backpressure. Every one has always told me the turbo makes all the back pressure you need, not sure if that's true though. But my truck is straightpiped and I have a banks intake with hardly any backpressure and no problems. Sounds like maybe injectors or glow plugs to me. But I'm no expert by any means so don't hold me to that

 

I don't think it's going to be injectors, the truck runs to smooth. I've always found that injectors cause a rough idle. Was the motor is warm it's a turn of the key to crank! I'm thinking it could be the glow plugs or the FICM could possibly be getting weak!

 

What oil are you running? If its really cold it could be thick, but when you plug it in it warms up and flows a little easier. These injectors are really sensitive. I would try running Rotella 5-40 synthetic. Mine starts down to -2 with that and one rev x per oil change and not plugged in. Not cheap but its a $40,000 truck that I need to start consistently! Cheap fix and easy if it solves your problem! If not its no loss but a few $$ . .

 

I'm running Rotella 15w40. It gets no where near that cold here, it may reach 25 a couple times a year! But it's definitely something to try! It stomps me The truck runs like a million bucks as soon as it spins over!!

 

You use motor craft oil filter? With factory cap? I understand sometimes they drain back to crankcase if not sealing drain in filter housing. . .

 

Yeah I use Motor craft filters and it's the factory cap. How would I check if it's sealed correctly? Take the cap off and see what's in the housing?

 

Popping the cap opens the seal to drain bowl to replace filter. . . My truck cranks a little but it also has 200,000 miles . .

 

That could be the case! I've heard from a couple YouTube videos that the oil draining down can cause a delay in start up!

 

Your ford dealer has been having seminars for techs for a few years, I was lucky enough to get invited. The filters in oil and fuel system are critical and the coolant has to be the same every time you add some. Generic coolant can become a problem as the passages in the oil and egr coolers are really small and sensitive to overheating. Generic coolant gels a little too and coolant flows at 75 gallons a minute. . .gel doesn't flow. .