tomlbby

I have a 97 s10 zr2 with auto tranny and the 4.3 with central sequential injection.i just bought from a guy that said he was doing a tune up and couldnt get to start.so far this is what ive done
replaced distributer
replaced fuel pressure regulator
did fuel pump test and keys up to 65 psi then slowly bleeds down to 40 after about 5 minutes.
I have the plenum remove now and fuel lines hooked back up along with fuel test gauge inline.i pulled all the popetts out so i could see if they were leaking buy during key up and they werent.
no leakage visiable in plenum area.
i pulled the fuel pump out some to inspect and all looks good there.
with fuel pump lines and connectors plugged back in like normal but with assembly up out of tank some so i could watch if anything wrong there during key up,No fuel leaks or anything i could see un normal.the wasnt any fuel coming back from return but im not sure if it returns ant fuel when just keying up?
the timing is dead nuts,cleaned throttle body and all sensor,cleaned map sensor,egr,new plugs,new wires,new cap,new rotor,new fuel pressure regulator,new coil,.also checked cat converter for cloging but its allready been gutted out.Im running out of pateince and ideas,PLEASE HELP

cleveland63b

do you have spark?

tomlbby

yes sir,great spark

tomlbby

its the fuel pressure leak down test that bothers me.?

tomlbby

anyone???

cleveland63b

if it has full pressure with the key on and running the bleed off wouldn't worry me, I'd have to look up spec to be sure but that's not really that bad of a bleed down. Extended cranking time would be the result not a no start.


Don't stray from the basics...spark fuel air and compression...is your fuel volume good? Did it start before he tried to do the tuneup? I had a 4.3 in this week for a no start the guy did a good full tuneup but didn't do wires....the wire on the coil was arcing to the coil body.

tomlbby

when turning key to start and fuel pump kicks on it goes quickly to 65 psi then starts bleeding down right away but slows up at around 40 psi now,not sure why its getn alittle less bleed off.i did pull the fuel sending unit out of tank to check it but didnt see anything noticeably wrong so i just set it back in tank but not clamped back down to do more leak down tests with.is there some tye of check valve or foot valve on the bottom or inside the fuel pump that may be leaking back?or any over pressure relief in fuel pump its self.??

tomlbby

it wont run so i couldnt tell you what the pressure does while running

cleveland63b

Well in theory if its full at key on and cranking then it will be running.

tomlbby

whats your thoughts on the pass lock security?may be my no start condition.no security light illuminating in dash but who knows ,maybe bulb is pulled out or blown.