Chevrolet Repair: 91 Jimmy wont start after sitting a few days, vacuum leaks, cmfi

Question
thanks Van for your advice.  Well I got around to checking it out and this is where i am at.  First of all my mistake it is a 93 jimmy.  Checked all things you mentioned and everyting seems okay so i splurged on the new fuel regulator with the new injector.  Installed it and before covering it up tested for spray out the end of the the tube that drops gas into the cylinder and nothing.  however gas did leak from everywhere it shouldn't have!  Where the six tubes come from the distribution housing.  I checked and o-rings seem okay so i assume a faulty part and having it swapped out.  My question is what should the fuel pressure be 13lbs or 40lbs?  I would have thought that fuel would have at least sprayed out the tube going into the cylinders?  i took it off and tried blowing through it and couldn't so i assume it needs high pressure.
thanks again!
Tim

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Followup To
Question -
Hi,
I have a 91 jimmy 4.3 litre that if it sits for a few days or a week won't start, cranks but not turning over.  When it is driven daily it starts fine.  I have changed plugs, rotor, cap.  There is a spark.  Fuel pump quit and is why it sat for a month, now that i have time and installed a new one it won't start.  There is gas reaching the engine. I can keep trying to crank it over and eventually would like start but I may have to install a new starter ;-) If you could please give some advice on what to check like fuel regulator, fuel pressure, egr, control module?
thanks,
Tim
Answer -
Hi Tim,
Check the temperature sensor for one thing.

http://www.chevytalk.org/threads/showthreaded.php?Cat=0&Number=1366279

I would also check the fuel pressure. If it is throttle body, there should be a full 13 PSI at the throttle body all the time the key is in run.

Make sure the egr valve isn't stuck open, or that there are no other vacuum leaks, including the brake booster.

Van


Answer
Hello Tim,
Yours will more than likely be CMFI, which is Central Multi Port Injection.
The pressure for it will be much more than a throttle body unit.
CMFI , with the ignition on, and the engine not running, should show between 54 and 64 PSI.
With the engine running, about 52 PSI is sprayed when the poppet nozzle opens, due to the injector solenoid opening.

But the fuel pump needs to supply that pressure.

Van