View Full Version : Won't start - think it's a fuel system issue
masonbhall
10-13-09, 08:27 PM
i have a 1996 4.3 liter less than 100,000 miles. I was having troubles starting it. It would turn over and after repeated tries eventually cough to life.
I replaced the fuel pump, with the help of a friend, because the shop told me that was the reason it wasn't starting.
It worked better for a week or two then I started having the same issues again. The guy at the shop is telling me that the fuel pressure was around 30. They are saying the pump i bought and just installed is bad and needs replaced. When i try to start it turns over and i am smelling fuel up by air filter.
I just don't think it is the fuel pump, but not sure what it is. Help?
Jongo88
10-13-09, 08:34 PM
What brand pump did you buy??? After market pumps last about that long.
masonbhall
10-13-09, 08:50 PM
i would have to double check the brand but it was a new pump and i got it from Autozone. Wouldn't the truck start with that amount of fuel or does it take more fuel pressure to even start?
Jongo88
10-13-09, 08:52 PM
30 is not going to get it.... I have seen new pumps not work out of the box.. Just remember. You get what you pay for...
Smelling fuel up by the air filter ??
Jongo is right... fuel pumps come bad, brand new in the box... also.. ENSURE YOU GET THE PUMP FOR A S15.. VERY IMPORTANT.. have them double check this. The fuel pumps for the bigger ones look the same, but do not put out as much volume.. (just experienced this one myself.. after arguing with parts chic at the counter twice.. :( )
Unfortunately, sounds like your spiders... which is not a cheap part to get... I just tried to find the post that shows GREAT detail on installation and everything for this. Its here somewheres and maybe someone remembers it and can post it....
Look.. its not hard to replace tho, or troubleshoot. The trucks not running at the moment, so remove the upper intake and inspect the inside. If you see pools of fuel in there, then you have a problem.
(Someone correct me if I am wrong)
If gasoline is located on the left = Fuel Pressure Regulator - The pressure regulator is the round grey thing on the LEFT hand side of the CPI. It may be 1 inch in diameter and can seperate around the seam. It has a small spring on the inside, and if you can see that spring, its definitely not good. This regulator can create a leak and not allow the correct amount of pressure (60 psi) required to start the 4.3 Vortec.
If pools of gasoline are on the right = Spider is leaking fuel - This can be from any of the 6 plastic tubes that run to each poppet. The entire assembly should be replaced.
When you replace the entire assembly, it SHOULD come with a new pressure regulator. These things are not the toughest thing in the world... they break and cause people heartache all the time. If you have the funds, I would recommend replacing the entire assembly.
How this causes you issues: When you go to start your truck, and you turn the key on, your fuel pump starts up and ensures your fuel pressure is at roughly 61-64 psi. It HAS to be 60+ in order to even start your truck. Once it gets there, and your truck starts, all it as to maintain is above 48 psi. BUT.. if your spiders or pressure regulator are slightly leaking, then the work of your fuel pump has just doubled. It trys to get up to 48 but your leak keeps it low, causing your fuel pump to run CONSTANTLY... eventually wearing it out.
I would take advantage or your warrantee for your recently purchased fuel pump, and swap it out for a new one. Then, if you see problems with your spider assembly, go get a new spider assembly and install it. This should be the only reasons you lose pressure. Believe it or not, alot of roadside mechanics do not realize the fuel requirements these 4.3 Vortec's REQUIRE. It is a very touchy thing with these engines, and can burn a hole in your pocket if not diagnosed correctly.
Check things out and get back to us. Everyone here is awesome and helps bump heads together to get what you need right the first time.. Hopefully... :)
spideyjected
10-13-09, 09:14 PM
Get either a GM or a Bosch pump, end of story. If it is not getting near 60 PSI it will not start. You may have an injector issue, but make sure it is producing 60 psi in fuel pressure first. My 93 CPI smelled like it should start too, but wuld not until the pump was replaced, twice. Airtex= crap.
994X4Blazer
10-17-09, 12:46 AM
has anybody checked the fuel filter????
masonbhall
10-17-09, 10:09 PM
[QUOTE=Craz;303534]Smelling fuel up by the air filter ??
Thanks to everyone for the ideas. I will be trying them to try and get to the root problem. Question; what did you mean by S15?
ENSURE YOU GET THE PUMP FOR A S15.. VERY IMPORTANT.. have them double check this. The fuel pumps for the bigger ones look the same, but do not put out as much volume.. inspect the inside.
S15 is the style Jimmy you may or may not have. If you have a Jimmy, then its either a BIG one (T15) or the small one (S15). Either way.. can be a difference in fuel pressure.
spideyjected
10-21-09, 07:08 AM
I thought S denoted 2 wheel drive compact and T denoted 4 wheel drive compact.
C denoted 2 wheel drive full sized, and K denoted 4 wheel drive Full size.
BigTruckDrivah
10-21-09, 08:43 AM
Engine code will help determine which fuel pump.
BigTruckDrivah
10-21-09, 08:44 AM
If it's a 96 then it's a "z" code I beleive.
Get either a GM or a Bosch pump, end of story. If it is not getting near 60 PSI it will not start. You may have an injector issue, but make sure it is producing 60 psi in fuel pressure first. My 93 CPI smelled like it should start too, but would not until the pump was replaced, twice. Airtex= crap.
What about Delphi pumps, are they any good?
masonbhall
10-23-09, 06:52 PM
S15 is the style Jimmy you may or may not have. If you have a Jimmy, then its either a BIG one (T15) or the small one (S15). Either way.. can be a difference in fuel pressure.
I am a novice at this, so bear with me. I have an Chevy S-10 extended cab pickup truck...is that also called a Jimmy?
trusconi
10-23-09, 07:50 PM
no it is a s15 or sonoma.
spideyjected
10-23-09, 08:52 PM
What about Delphi pumps, are they any good?
Isn't Delphi GM? I think anyway.
spideyjected
10-23-09, 08:53 PM
I am a novice at this, so bear with me. I have an Chevy S-10 extended cab pickup truck...is that also called a Jimmy?
No, that's just an S-10. The S10 "if it's a chevy" never got a fancy new name.
12sws27
10-23-09, 09:03 PM
I am a novice at this, so bear with me. I have an Chevy S-10 extended cab pickup truck...is that also called a Jimmy?
I think he thought you had a GMC. I think what he's saying basically is to make sure you get the right pump for your s10 and that they don't give you one for a fullsize that might look identical but not supply enough fuel.
Isn't Delphi GM? I think anyway.
Alot of factory parts on GM are Delphi. Just like Ac-Delco.
I think he thought you had a GMC. I think what he's saying basically is to make sure you get the right pump for your s10 and that they don't give you one for a fullsize that might look identical but not supply enough fuel.
Alot of factory parts on GM are Delphi. Just like Ac-Delco.
I always thought Delphi was a part or division of GM,I knew that Delphi also filed for bankruptcy here a while back,but never heard of all of the details.
I really don't care for Airtex, sell a few of these and feel pretty guilty, they ain't the best.
Seems like my S15 GMC surges,not real bad but you can slightly feel it surging.I changed fuel filter, had the throttle body redone, but it still surges.
Having a heck of time trying to figure what's up with that.All new plugs and wires, cap and rotor, but it still has that slight surge.
Maybe I should run a scan on it to see if there is anything shows up
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