1999 chevy astro wont start has spark and fuel preasure someone looked at and said they think a injector might be bad under the plentum does this sound right before i start tearing apart motor

are they electric or mechanical..auto shutoff relay may be bad..

Well the alternator won't have anything directly to do with an engine not starting. Only if the battery is dead because the alternator is not charging it.
If the engine cranks but does not start, someone will need to figure out if you are lacking fuel to the injectors, spark to the plugs, or compression to proceed with testing.

Someone will need to figure out if you are lacking spark to the plugs or fuel to the injectors to proceed with testing.

They weren't very good mechanics. Sorry

Basics are to spray a little starting fluid into the intake and try to see if it's fuel related. Do this with an extinguisher handy. If it fires just a time of two, check for plugged fuel filter. Then check for dead fuel pump.

If it didn't hit a lick, pull one spark plug wire off, stick a screw driver in the lead, holding the insulated part of the driver hold it close to the motor and have someone turn it over to see if it has spark. If it does not, the computer is bad or the key switch may be bad.

You can take a paper clip in the computer plug under the dash and turn on the key. On the dash the lights will give you any defect codes. If you you are unsure, ask someone at a local parts house to help you.

Good Luck,
dc don

bad distribuitor cap and rotor trust me on this one

make sure the points in the distributer are lined up and check the condition of the cam sensor and crank sensor

how much fuel preasure ? this van needs 54 psi to start the lowest 45psi,make sure theres enough preasure. if timing is on and theres spark and you have preasure it should start unless!! there no injector pluse, check the injectors for power and pluse.if you spray throtlebody and it starts then we know it a fuel problem start there, let me what happens.

check the timing belt, make sure it didnt break or jump, also you must make sure the feul has enough preasure, try sparying starting fluid into throtlebody see if it starts if it does then could be injector or low fuel preasure start there.

THE FUEL PUMP IS BAD.

if your losing fuel pressure after the pump runs the drain back valve in the pump has failed.

and i doubt that you are seeing enough fuel pressure to run a vortec engine.

low fuel pressure equals a non running vortec

Chk. all fuses, there is a fuse for injectors, If no spark at plugs chk ignition fuse and switch, and chk. fuse for e.c.m. Can't help with diagram. Parts dept. chevy dealer will print you one out.