Start up engine cranking long

My truck takes like 5 seconds of cranking until it starts. What should I look for/how do I diagnose the problem.

 

I’d start checking codes. Then cleaning TB and MAF. Disconnect battery negative x a few minutes. If spark plugs more than 100K or 10 yrs change those.

 

And check your engine air filter.

How old is your battery???

 

Fastest way to test?

Get a can of starter fluid (ether). Before your next cold start, pop off your intake tube from the throttle body, hold open the throttle plate, and spray a 1-2 second shot into the back of the throttle body. Put the intake tube back on. Start the truck.

If it fires immediately, you have a fuel delivery problem. If it doesn't, you probably have an ignition (spark delivery) problem, or other electrical issue.

There are some cases where fuel delivery problem can be an electrical problem. Some that come to mind:

• You have a V8, and during last timing belt change, someone did something fucking stupid, like misrouting the crank position sensor wire, and it's gotten eaten thru by a belt. Proper routing info is linked is in the megathread sticky. The ECU won't allow the fuel pump to stay on if it's not receiving running-state input from the crank position sensor (for safety - in case of crash, engine not running, you don't want fuel pump to be pumping fuel everywhere).
• Your fuel resistor is going out, and not allowing the pump to run in low-flow mode.
• Your fuel pump is dying; try leaving the key in ON position for 10 seconds before you flip it forward to crank; does it fire faster? (Note: I'm not implying the fuel pump begins running in the ON position; it doesn't, it starts running when you turn the key to START, then continues running when the ECU receives confirmation from the crank position sensor saying "I'm running!")
• Fuel pump relay is bad, and not tripping the fuel pump power circuit between low-flow (i.e. pushing pump power through the pump resistor) mode, and high-flow (i.e. pushing direct full power to the pump).
• You've got a burnt EFI fuse or other similar fuse up under the hood.
• You've got corrosion in your wires, a bad ground, a shorted cable (i.e. cable bundle pinched between frame and body or similar), rodent damage, or ECU failure

I think more often than not, we see people who have long starts when hot. And I rarely see those issues ever getting solved.

You could throw parts at this all day long. But what I recommend to you is, grab a copy of the FSM for your specific model and use the diagnostics section. It'll give you 75% of the workflow to test this stuff, essentially revealing many of the diagnostic steps the tech at stealerships will use. See the megathread sticky to uncover where to grab your copy for 1st gen trucks.