My dads 1996 s10 will not start after sitting only 5 mins. If you put some gas in the throtle body or spray it with starter fluid it starts right away. We checked the fuel pressure and it was like 45 psi and the manual said its suposed to be between 55 to 61 psi. When i start it with starter fliud it goes up to 58 psi and it runs fine after you get it to start with starter fluid. I have changed fuel filter all spark plugs and wires all the relays seem to kick on fine. I just dont know does 45 psi really make a differnce from 55 just curious. It dosent really seem like its spraying any fuel when trying to start. Is it fuel pump, fuel pressure regulator or fuel injectors plz help if you have any ideas. thanks

 

i forgot to say its the 4.3L v6 CSEFI injection which pretty much means the 6 injectors are all in the middle of the manifold

 

theres a couple relays that controll some of the injector pulse and fuel pump priming. if i remember right they are located on the left side inner fender. near the brake master. check them to see how well they work. it is having extended crank problems. pump doesnt run till it sees oil pressure.

 

the oil pressure gauge goes up when i crank it, but i will check to see if there are relays over there thanks any more ideas

 

PUMP......easy, replace it, it's fixed......have a nice day....

 

Don't listen to the guy above. If your pump is putting out the right amount after it starts then it's not the pump at all. Key the truck up a couple times. You should here the pump kick on for a couple of seconds. Check fuel pressure. If it fires right up when the pressure is high, then you should just replace the regulator.

Randy

 

I've heard those injectors need the pressure to pop open, and are not too reliable below recommended pressure. (not fact, just what i heard).

Install a fuel gauge on fuel line, cycle the key to on (don't start it) and watch what the pressure does after the pump stops priming, see if it holds that 45 or bleeds back down slowly.

Find the rubber section of fuel line for the return line behind the block and crimp it off (pinch it with some vise-grips). Cycle the key to on again and watch the pressure. If it goes higher than before (like to the proper pressure) and holds better, then your fuel pressure regulator is leaking.

Hope this helps,

 

i did let the fuel pump prime then turned the ignition off waited awhile turned it on heard it prime again i did that a couple of times but it never went higher then 45psi. But i am going to wait awhile and see if the pressure drops. Because once you get the car running and let it warm up if you shut it off you can fire it back up but if you wait longer then like 5 mins it dosent get any fuel and wont start until you use gas or starter fluid. I am starting to think it is the fuel pressure regulator. I just have to take the throtle body off and the cover and its toward the firewall, so i wanted to make sure im fixing the right problem first. So thank you for the help so far i will take any more ideas if anyone has any.

 

This is a dumb argument, yes the pump can mantain enough pressure to run the truck, but if the presure isnt enough to prime and start the truck YOU NEED A PUMP!.....

 

Yes the pump fails more than the other components, but it isn't the only cause for low pressure. The pump supplies fuel to the feed line. The regulator closes off the return to create backpressure. If any components like fuel lines, regulator, or injectors are allowing that pressure to leak or bleed off elsewhere, then the pump could be fine and you still will have low pressure. Better to properly diagnose the problem rather than throw parts at it. Especially parts that you need to drop the tank to put on.