My 2500 hd has problems cranking sometimes it always cranks but sometimes spits and sputters, I've replaced starter, alternator, and has a brand new battery, any ideas what could be going on? Thanks

 

Need to help us with your terminology please. "Trouble cranking" suggests to me starter does not turn motor over at normal speed. "Spits & sputters" to me means it's turning over fine (cranks well) but is having trouble starting. Please clarify and give more details.

 

The truck cranks it's just sometimes it takes 5-10 seconds to actually fire up and I don't know what it could be

 

Thank you, & BTW welcome to a great Chevy source of information!
Disclaimer - I'm a veterinarian, not a mechanic. I'll bet others will say you have a fuel delivery problem - try keying on & off 5-10 times before hitting the starter to prime the fuel system.If it fires right up you need to address a check valve failure in the fuel lilne.

 

Does it do the same thing when you turn it off and restart it very soon after? Does it only do this after sitting for a while?

 

It'll do it occasionally while it's still hot but mostly when it sits for awhile sometimes it may go a week or two without doing it

 

I agree with Rednucleus that it is the check valve in the fuel pump assembly. You could change the fuel pump or add an inline check valve in the fuel line near the gas tank.

 

#1 don't throw parts.

A good mechanic (ie isn't fired and makes money) ALWAYS does this.

Exclude what you know isn't bad. Test whatever you don't know is bad: bench test. Make SURE it's bad before you replace it.

You'll save both time and money doing that. That's why good mechanics do it. Simply, "it's just what you want to do".

 

It could be many things.

Try this: crank it 2 revolutions shut it off. Wait 5 seconds. Turn on the key/lights for 5 seconds. Now crank it. If it fires right up then you miight have a fuel pressure issue. BUT IT MIGHT BE NORMAL.

MINE IS PERMANENTLY LIKE THAT - due to some "issues". IDK. I'm never fixing it. I have a way to start it 100% of the time.

Mine's a 2001. 2001 and earlier trucks didn't yet have "quick start technology". Don't expect them to start first turn when they get older.

Now on my bike - carbeurator - having sat for a week - NEVER EVER starts without cranking a few times.

HERE'S A TIP FROM THE 1980'S: do not over-crank you'll burn out your starter. Crank only 5 revs at most and let it sit a little. cars back then frequently got "into modes" where sometimes they wouldn't start

back to 2001. if you went into a store came back out too quickly - any 90's or early 2000 truck would have issues starting. "first crank start" ELECTRONICS was a feature that only came out in the 2000's

-----------------------------------------------
if you have a "pre-first crank start electronics", and you follow the procedure above and it ends up 2 cranks, keyoff, then 2 cranks starts: i'd say: IF IT'S NOT BROKEN DON'T FIX IT. nothing wrong with that