2000 Chevy Express won't start, help!

Hi I have a 2000 Chevy Express van with 22,500 miles on it that
won't start. The engine is a 5.7L "R" Vortec which was running fine
until Friday after lunch. I pulled the doghouse and checked the cap
and rotor, replacing those since there was a little buildup on both.
There is plenty of spark off of the coil, and the fuel pump runs when
I turn the key to 'run', with pressure at the fuel rail. I removed the
intake snorkel from the throttle body and the van runs on carb cleaner
fine, but of course dies out. One buddy said to change the Crank
sensor which I did to no avail saying this fires the injectors.
Obviuosly its not getting fuel, any ideas?

Thanks,

Bush

The Vortec requires alot of pressure to open its poppet valves at each
cylinder. Vortecs work differently than normal engines where electric
injectors that are placed right near each cylinder. In your engine,
there is a bank of 8 fuel solenoids on the center of the intake
manifold under the plenum. Each solenoid dispenses fuel through
individual plastic pipes to a poppet valve at each cylinder. Fuel
pressure needs to be about 55 to 63 psi to force these poppets open.
Sometimes they stick and normal pressure won't open them either. It
would be fairly unusual that most/all of yours stuck (though it
sometimes happens in GM world), so I would look at exact fuel pressure
and suspect a weak pump or bad regulator.

You can tap into the big harnass going "into the intake" with the help
of a wiring diagram to see if the injectors are being operated. There
are eight different colored wires, one for each solenoid, that apply
ground from the PCM to the solenoids in aprox. 5 millisecond bursts. A
led style testlight can be used here to look for flashing activity, or
a noid style piercing test light will flash really bright. Regular
noid lights have injector harnass terminals on them and would require
removal of the upper plenum, so they would be the wrong tool to use
here, unless you modified one to pierce/backprobe into the big harnass.

Toyota MDT in MO

On 14 Feb 2005 15:56:07 -0800, "Comboverfish" >
wrote:

>The Vortec requires alot of pressure to open its poppet valves at each
>cylinder. Vortecs work differently than normal engines where electric
>injectors that are placed right near each cylinder. In your engine,
>there is a bank of 8 fuel solenoids on the center of the intake
>manifold under the plenum. Each solenoid dispenses fuel through
>individual plastic pipes to a poppet valve at each cylinder. Fuel
>pressure needs to be about 55 to 63 psi to force these poppets open.
>Sometimes they stick and normal pressure won't open them either. It
>would be fairly unusual that most/all of yours stuck (though it
>sometimes happens in GM world), so I would look at exact fuel pressure
>and suspect a weak pump or bad regulator.
>
>You can tap into the big harnass going "into the intake" with the help
>of a wiring diagram to see if the injectors are being operated. There
>are eight different colored wires, one for each solenoid, that apply
>ground from the PCM to the solenoids in aprox. 5 millisecond bursts. A
>led style testlight can be used here to look for flashing activity

I saw one of these at the auto parts store, and it seems like a good
idea to get a quick and dirty reading on a hi voltage line. Problem
with it is, even though the signal may be present, does -not- mean
that the injector is working ;0 Only way I _know_ of verifying
injector is working, is to listen to it with a stethoscope to HEAR the
mechanical clicking of the valve. Sure you can have a perfect signal
on the injector line, but that doesn't mean the jet isn't clogged, or
something isn't amiss with the pintile valve. Or even that the
injector is doing anything at all.

>, or
>a noid style piercing test light will flash really bright. Regular
>noid lights have injector harnass terminals on them and would require
>removal of the upper plenum, so they would be the wrong tool to use
>here, unless you modified one to pierce/backprobe into the big harnass.
>
>Toyota MDT in MO

Bushleague wrote:
> Hi I have a 2000 Chevy Express van with 22,500 miles on it that
> won't start. The engine is a 5.7L "R" Vortec which was running fine
> until Friday after lunch. I pulled the doghouse and checked the cap
> and rotor, replacing those since there was a little buildup on both.
> There is plenty of spark off of the coil, and the fuel pump runs when
> I turn the key to 'run', with pressure at the fuel rail. I removed the
> intake snorkel from the throttle body and the van runs on carb cleaner
> fine, but of course dies out. One buddy said to change the Crank
> sensor which I did to no avail saying this fires the injectors.
> Obviuosly its not getting fuel, any ideas?
>
> Thanks,
>
> Bush
Does the pressure in the fuel rail hold? At least for 10 minutes at 40
or 60 psi. It may also be the fuel press. regulator attached to the side
of the injector assembly that is under the intake plenum. Look thru the
throttle plate to see if half the internal part of the intake is
unusually clean. Or fuel washed. This is a sign of fuel leakage from
the assembly.