Johnny-O

89 T/A 5.7 tpi,

Started running like crap and backfiring thru tailpipe. Throwing flames out of the tailpipe (straight pipe). i figured it was time to go over everything.found faulty fuel pressure regulator. which was hemorrhaging gas directly into the intake. so i did all my maintenance at once. New fuel pres reg,plugs,wires,cap,rotor, accel coil , as well as new upper and lower intake gaskets.


Now it wont start at all. it attempts to start at WOT. No backfiring

No codes, injectors tested good, firing order correct, vacuum hoses connected, checked tps/maf/map. fuel pressure OK and i even combed over all the wiring harnesses

please help. this thing is killing me!

Tuned Performance

iTrader: (92)

Sounds like leaking injectors, how fast does fuel pressure drop ?
Have you primed the fuel system and pinched off the return line to see if it bleeds off fast.
It should hold pressure for 5-8min. if not start pulling plugs and looking for excessivly wet ones. If the injectors are a greenish body they are multecs and are very problematic.
Contact south bay fuel injectors and get a set of bosch 3s 22#hr.

Johnny-O

I cleaned the injectors and verified that they are functioning. doesnt mean anything i guess. everything was fine and then over the course of a few days it got worse and worse. injector resistance is 14-15ohms across the board.

Tuned Performance

iTrader: (92)

http://www.southbayfuelinjectors.com...rvette-c4-l98/

Johnny-O

so it seems like i have a fuel pump problem. psi seems awfully low but the pump sounds heathy. i am also losing almost all fuel pressure within a minute or two. do these have a check valve in the fuel line or pump that could be faulty? if the pump was weak would it still cause it to try and start at WOT?

bigal55

iTrader: (1)

How low is the pressure? There is a short hose connected to the fuel pump pressure side that goes to a pulsator which is part of the fuel pump/sending unit. If this hose is ruptured you will not build pressure or volume. In any case, you will need to drop the tank to remove the pump assembly. HTH!

Johnny-O

fuel pressure is about 28psi. fuel pump resistance is 2.78ohms but there is a check valve on the sending unit is split wide open.

Tuned Performance

iTrader: (92)

The peace on the pump is a pulsator, junk it and install a hose with clamps in it's place.
Sounds like you found where you pressure loss is .

Johnny-O

sorry for the delay. yall know how much fun those tanks are to remove. i replaced the entire sending unit. it was in overall rough shape and also had a non responsive float. injectors didn't leak but i will replace anyway. REPLACING SENDING UNIT HAS RESOLVE WHATEVER ATTITUDE PROBLEM IT HAD!

THANK YOU FOR ALL THE HELP!!!!