venomhp

iTrader: (13)

On my 02 z-71 5.3, sometimes when you go to start it, it will just sit there and start cranking and wont start up, but always on the second try it starts up instantly...when you turn the key to on, you can hear the fuel pump turn on, its never a constant thing, like when the engine is cold, or warm, its just sporadic and really annoying. More embaressing than anything when you see a jacked up truck not wanting to start... anyway i dont like putting the extra "mileage" on my starter that I dont have to... any Ideas?

SparkyJJO

iTrader: (11)

Does it sound similar to this?


That is my car, a V6 and recorded on my cell so you might not hear it too well That was minor btw, it tends to be harder and longer than that. Seems that when it is really cold outside it does better than when it is a bit warmer.

I was told it could be the check valve in the fuel pump going bad so the fuel runs backwards back into the tank when it sits, or a bad fuel pressure regulator, a weepy/seeping injector, or an intake vacuum leak (causing it to lose fuel pressure somehow, not sure exactly). I haven't checked around much on mine, I just deal with it for now. I don't want to find out it is the check valve in the fuel pump since I don't have a few hundred to dump on a new pump

venomhp

iTrader: (13)

Kinda... it will just sit there and crank normally, but theres no combustion. Its like its not getting fuel. but the second time you do it it barely cranks and it fires right up, it doesnt try to stall out or anything its just weird. i was thinking that it could be one of these possibilities...fuel regulator like you said, maybe pump but I hear it turning on, ignition module, or maybe somethin else. I changed out the fuel filters about once a year and its still the same, right now my truck is in storage but i gotta drive cross country in it in two months so I was going to see what you guys thought-Thanks-Mike

fuseone

ok try this cycle the key a few times on the on postion but not to where it cranks do it like 3 times and then try starting it and see if it starts right up. but dont just cycle it real quick do it where each cylce takes about 2 or 3 seconds. and come back and let me know because it kind of sounds like the fuel pump

venomhp

iTrader: (13)

Called my buddy to and he did that and for the first 10-12 times it didnt have a problem, on the 13th or 14th time it did the same thing, everytime you can hear the fuel pump turn on, i dont have a fuel pressure guage otherwise Id be able to make sure the fuel pump was pushin fuel everytime...really dont feel like replacing the fuel pump unless I have to, its got 130k so its comin up but its got a full tank of gas in it right now...(truck is back home in TX in storage for the next two months til I get orders)

fuseone

yea to me it seems like its a bad check valve on the fuel pump.

venomhp

iTrader: (13)

what exactly does that do?

sixvi6-camaro

iTrader: (9)

the check valve keeps the fuel in the lines and fuel rail from draining back into the tank when you shut the car off.

So.. Normally when you shut off the car the valve holds fuel in the lines and rail so the next time you start it there is fuel right at the injectors and the car starts right up as soon as it cranks and the pump turns on.

If the check valve goes bad.. when you shut off the engine all the fuel drains back into the tank.. the rail and lines empty out so the next time you go to start the car the car has to crank until the pump refills the lines and and fuel rail and the car starts.

the major problem is the time running the pump with no fuel will heat it up and could burn it out real quick and all the cranking can do the same to the starter.

venomhp

iTrader: (13)

well if thats true then wouldnt the truck start up if I left it cranking long enough? because It will just sit there and crank, like its not getting fuel at all...then when you do it again it fires right up like its brand new

fuseone

well venom to me that sounds like a bad check valve thats all i can say. i know its not a fun job but if i was you id replace the fuel pump

venomhp

iTrader: (13)

alright Ill replace it when I get back home after a couple weeks before I gotta drive cross country...better safe than sorry I guess...Ill update the thread in a couple months when I get it replaced

venomhp

iTrader: (13)

*update*
alright, the check valve was replaced and its still doing the same thing...so im going to be replacing the entire fuel pump/sender and seeing if this fixes it. Also the fuel guage on the dash has been bouncing around for the last 10k miles or so and ive heard thats a precursor to the fuel pump taking a huge crap right when its most convienant for you (in the middle of nowhere)

joshp14

iTrader: (5)

Pull the vacuum line off the fuel pressure regulator and spin it so the nipple is pointing down. If you get fuel drips out of the nipple, replace the regulator.

I assume you meant the fuel pump was replaced when you said "the check valve was replaced"...as the check valve is internal to the pump on most applications.

venomhp

iTrader: (13)

gm replaced it while it was under warranty at about 60k miles, trying to figure out the same problem and then it would never do the same thing in front of them so they looked at me like I was a retard... so to look like a retard again..the fuel pressure regulator is located on the back of the fuel rail correct?

venomhp

iTrader: (13)

EDIT* called my buddy (previous owner) and said that gm replaced the fuel regulator, not the check valve, so im still on track with replacing the fuel pump-thanks

joshp14

iTrader: (5)

The regulator on that truck is on the drivers side of the fuel rail with the vacuum line coming out the top of it.

venomhp

iTrader: (13)

^^^ preciate it!!