Wanted to say to everyone! I am new to the forum..I bought a 96 Blazer for my son..For the love of mankind, I need you guy's help. It will not start without pouring gas down air butterfly..It's a 4.3 with Csefi..Once it's started>>it runs like a champ..But if you let it sit longer then ten minutes, you have to re-prime it.. I have replaced the fuel pump (with new screens too)..new regulator..new fuel filter.. Put pressure guage on it and it reads 10psi with switch on...and falls..The old pump did the same thing that's why i replaced it.. While it is running, it holds 61psi and holds a steady pressure..I am stumped...!!!!! any suggestions and thanks for taking the time to respond

 

Back probe the power wire (gray) to the fuel pump and watch the voltage when you key on. It is possible that you have a poor connection at the pump, and once the voltage kicks up from a running alternator, the pump runs normally.

The other possibility is that the poppet nozzles and injectors are fouled, but that wouldn't make sense with the symptoms you are experiencing... If the nozzles/injectors were leaking, then additional fuel down the intake should only cause it to choke off even more from the overly rich condition.

I replaced the SCFI spider in my old Bravada with the updated MFI spider. When I was doing a lower intake manifold gasket change, I had pulled the poppet nozzles out of their bores and pressurized the system (after reinstalling the fuel lines). Three of my nozzles/injectors were leaking. Decided it was time to replace the spider right then and there. Mileage and power were back to what they should have been. Not saying that this is the cure for your problem, but something else to check for sure.

 

Thanks for the advice.. Think auto zone sells that complete wiring set up for like 9 bucks..so thinking i might go ahead and replace it just for s@#% and giggles and then check the voltage.. I will keep everyone posted

 

ok replaced the harness.. and put new battery in...still the same result..i check the voltage at the pump and it shows 12 volts...still with key on it shows 10 psi with initial purge..when i pour gas down the butterfly...engine starts..it goes to 65 psi...running it drops to 60 psi..according to the book that should be right.. Next question for anyone is; this truck has had the quick connect fuel lines cut by the idot that had it before me..they kept the ends that attach to the tank but use regular fuel line to attach to the metal lines that run the frame..guys at my local junk yard said that was the problem..they saidlines are design to help build pressure for the system..Is this true?? I can't find any information about the quick connect lines.. Thinking once i tighten the clamps down on the lines, that it is restricting the flow..what do you guys think??

 

Lines are lines. If they do not leak, they are not the problem. If there was a restriction, it would show up when the engine is running and at high RPM.

 

that's what i thought but wasn't sure..just running out of ideas