jdracing

i found an 84 5.0. ho 5-speed that had been sitting for 5 years with no carb.
first day i got it home i put carb on and hooked up new battery.
after about 5 minutes of priming it fired right up.
it will only run about 8 or so seconds before it spits back thru carb. and cuts off.
pump gas and goes thru same process all over.

do the 84 cars have the same dreaded fuel pump problem as later models?
could fuel pump be bad as reason not staying running?

is there a trick to checking for that,or other possible reasons?
i know the car needs oil change and tune-up.
but if it cranks at all,it should stay running without tune up??

engine sounds really strong,and can't hear any knocks,etc.

i did put new distributor cap,rotor button,and wires.
could it need new plugs as well to get it to stay running long enuff to dial
in timing,etc?
not a mechanic,but know a little bout motors,etc.

any and all suggestions are greatly appreciated.

thanks,
jd
[img]84 z28 5.0 ho 5-speed2.jpg.JPG[img]

8t2 z-chev

car should also have an engine mounted mechanical
pump-the electric pump is a low power boost pump
meant to reduce the chance of vapor lock with the
L69 and later LG4 cars that have electric fan. earlier
L69 cars(until sometime in 1984)did not have the boost
pump.The pump is a turbine type with no check valve,
so fuel can easily pull through it if it is not operating.

jdracing

so,are you saying they all should run even if tank pump is bad?
or is it just 84 back,or just l69,etc?
are you calling the car an l69?
if so,are they diffrent than standard 305 cars?
jd

8t2 z-chev

if mechanical pump is working they will run with the
boost pump inop.
"L69" is code for the mid 1983-early '86 "5.0 H.O."
engine,that engine has several differences over the
standard"LG4"305;one point higher compression
ratio,slightly larger exhaust manifolds,larger exhaust
pipes,corvette catalytic converter,350 CFI corvette
cam,electronic spark control,'84 vette electric fan,
dual inlet air cleaner to produce a rated hp of 190
(200 with premium gas)vs 145-155 hp of the LG4.
Problem definately sounds fuel flow related-
if by "pumping the gas"you mean pumping the pedal,
that kinda indicates a carb problem-dirty,gummed up
or if it was "kitted"that may have been done wrong

jdracing

carb was not on car when bought.
i got carb on trade and was said to be good.
now that isn't always the case when someone says
one thing that may be another.
it does run good for few seconds then spits back thru
carb as if it is slightly off time,or have seen bad
condenser do same.
not even sure if it would have that type condenser?
till now,i have only worked on 60s-70s small blocks
without hei,etc.
this is all new to me...i am confident motor is good,so
guess i'll just keep fooling till i get it right.
think i will put new plugs in tomorrow though i don't
think that is gonna solve the problem of engine not
running as it should at idle.
i wish i knew more about these things because i can't
afford to get a real mechanic under hood.lol.
i did notice it only has electric fan.
is that all it came with?
no fan on front of cam pulley?
jd