Ihave a 1998 Blazer 4x4 with 4.3 vortec v6 and it turns over but does not crank. my friend tested the fuel pump and its got pressure soI replaced the fuel filter and that wasnt it. I replaced the dist cap and fuel pump relay and still not it. thenI was told it was the mass air flow sensor so I replaced that as well and its still sitting in the yard. not sure if its got something to do with the fuel or firing.i did get it canked once and drove it around the block and it acted fine andgot back to the house and switched it off and on a few times and it startedright up but after leaving it sit for a while it did the same thing again and now it wont start at all.any ideas??? thanks

 

Sounds like classic fuel pump (almost) failure. You need 60 psi fuel pressure to start the vehicle. Just because you have fuel pressure doesn't automatically mean you can get the car started. You MAY have other problems, but your symptoms are screaming weak fuel pump. My '96 did the exact same thing, cranked and cranked but would not start. I'm in the process of replacing the fuel pump right now.

 

Does sound like fuel pump, dont, I repeat dont buy cheap, you only want to replace the pump once, try to get it in the air so you have plenty of room, dont have hardly any fuel in tank, BE CAREFULL OF THE VENT TUBE FORWARD OF THE TANK!, if you bust it off your hurting, disconect battery too, anyway, do some research on it, get a helper, and take your time, buying a new sealing ring is wise as well, be sure to really clean the area of tank where pump fits in, you will be glad you did, hope this helps.

 

Yeah it sounds like a failing pump to me, but you should install a fuel pressure test gauge to verify it...should be 60 PSI like someone said earlier when you key it up. And just for future reference "turns over" and "cranks" are the same thing...you meant to say "cranks and won't run".