Pirate 4x4 banner
1 - 9 of 9 Posts

·
Registered
Joined
·
222 Posts
Discussion Starter · #1 ·
97 K1500, 4.3 Vortec, 5 spd
On the first try, it will crank and crank. But no start. Then stop, and try agian and it fires right up. Is there a faulty check valve?
Thanks,
Scott
 

·
Registered
Joined
·
543 Posts
fuel pump is going bad, my s10 does the same thing every morning, do yourself a favor and only replace it with a gm unit...kris
 

·
Registered
Joined
·
1,723 Posts
sounds like a typical no start problem....

+1 on the fuel pump.
 

·
Registered
Joined
·
3,307 Posts
what happens is the fuel pump does not put out enough pressure to open the injectors. its the pump. we have done a couple dozen of them this year. :D
 

·
Registered
Joined
·
509 Posts
hummm ive noticed the same thing since i swaped out my carb. before witht he old dirty bad gasket carb, it would start no problem, then i buy a rebuilt one from some guy and now i cant ever do a cold start on the first shot. hummmmmm.
 

·
Registered
Joined
·
697 Posts
get a fuel pressure tester and test your fuel pressure after priming it once with the keys.
 

·
Registered
Joined
·
1,014 Posts
what happens is the fuel pump does not put out enough pressure to open the injectors. its the pump. we have done a couple dozen of them this year. :D
That makes no sense at all. The injectors don't need a bit of fuel pressure to open. It is opened electrically. Anyways, that is a very common problem with that motor. Most of the time the check valve in the fuel pump module goes bad and lets the fuel bleed back into the tank after the vehicle is turned off. So when you jump in and crank it, the lines must be filled again, and since those motors are very picky, and won't start without the exact fuel pressure you get the extended crank. One thing to try to verify the problem is to cycle the key on and off a few times before you try to crank it. It will probably fire up alot easier that way. You will need the whole fuel pump module, you can't service the parts separately.
 

·
Registered
Joined
·
462 Posts
on a 4.3 the injectors are centally mounted and there is individual poppet nozzles at the end of each plastic hose for every cylinder, . put a fuel pressure gauge on it. the injectors will fire but the poppets will NOT pop open with any thing under 55 psi of fuel pressure. if less pressure replace the pump.
 

·
Registered
Joined
·
35 Posts
Not tryin to be a dick, but it's 45 PSI but thats still astronomically high. thats the problem with the stock poppet vavles is that if the pump doesn't put out enough pressure, the engine dies. if the poppet vavles get clogged up a little bit they don't squirt.

I have replaced the fuel pump on my 4.3 about 4-5 times now (i don't like to remember) and it isn't fun. just unbolt the 6 bolts holding the bed on and get some help lifting it off. than just switch out the pumps. the hardest part is forking up the sick amount of cash they ask for the piece of junk plastic.
 
1 - 9 of 9 Posts
Top