Shouldn't there be fuel pressure after engine is shut off?
 

I am curious about the fuel pressure on a TBI system.
Shouldn't there be pressure once you turn the key on with the engine off?
I am getting 0 until the engine is running,then I get 12 psi.
I installed a new pump from Auto Zone and now am wondering.

Suggest you double check..
I never saw an FI system that the pump didnt run at key-on, granted the last time I checked was on a 350 TBI
So if you have to crank few seconds to start, and you have to crank many seconds after fresh oil filter, your relay may be shot, because only the oil pressure switch is running it.
Look up the diagram for your pre-95 ECM test socket, there's a way to energize the relay by shorting pins in it.

usually. the fewtimes i have checked with a gauge it should stay or go down really slow. if it drops within a second or two theres a problem

This is on the W engine I rebuilt and installed the throttle body.
The reason I am asking is because of the hesitation trouble I have been having about 1600 rpms.Sometimes backfiring.
When I checked the fuel I open the line up about the front of the valve cover and installed the new gauge.I watched while I turned the key on and there was no pressure.
I could hear the pump run for maybe 2-5 seconds then shut off.
Started the engine and it went up to 12 psi.
Shut it down and 0 pressure...the pump runs for about 20-30 seconds after shut down.
The older Haynes books doesn't say anything about pressure other than while engine is running.The newer one 94-2004 says 9-13 engine not running.
I have been hearing bad things about autozones pumps after this and wanted some others input.
Thanks.

Good evening guy's.
Thought I'd check in with some results.
I retested the fuel system this afternoon.I hate and am glad to tell you I may have been mistaken.
Seems that harbor freight's Chinese junk fuel gauge tester is leaking off.
I tried to seal it and wound up bending the inside so it won't even move anymore.
Before I killed it I was able to get the needle to go up to about 10 then dropped off to 0.This was with the ignition on but not the engine.
So maybe it has been good all along,just the junk gauge was wrong.
So they got my money.I'll have to find another good one,preferably one made in the USA!!!

I consider Harbor Freight tools to be disposable at best. Get a decent fuel pressure tester. It's one of the best and most useful tools I've ever bought. I bought it originally for my '94 Jimmy and have used it several times over the past four years. It's definitely something everyone with an S/T series truck should own.

A month ago I noticed Lowes had had a 0-100 gauge for about ten bucks. If the rest of the kit works check it out and see if it has same threads, probably will. And it should last a while.. it's for well pumps.
- It's not so much where it's made, it's how much the wholesaler is willing to pay the mfr and their quality specs.

We wouldnt be in this trade mess if US mfrs hadnt been making junk. Dont forget I lived through this since almost everything made in Japan was crap.

Autozone pumps are crap, but that doesn't seem to be your issue. The pump itself is pumping fuel (verified by your reading at 12psi when running). The issue is that the fuel is leaking after you shut the truck off. The fuel could be leaking from one of the lines, you could have a stuck injector, your gauge could be leaking, could be many things. Either way, it appears you are not holding the pressure after you shut off... nothing to do with the pump.

Verify that you can eliminate any leaks in the gauge and connections, then run the test again. If you still can't hold pressure after turning the truck off you need to see where that fuel is going.

Hello all.
I agree with you and pettyfog 100%.The gauge was leaking around the thread and out the bottom of the gauge.
I have all new lines,injectors and rebuilt the throttle body.
I ordered a new Actron professional fuel pressure testing system from Summit Racing.It looks like it is a good quality product made in the USA.
A little pricey but the compression tester and vacuum gauge I bought years ago has held up pretty good.It should be here in a day or two.
After thinking about it I guess I shouldn't hit on harbor freight so much.I have bought a few welding items that hasn't died yet from them.Though I hardly use those ones.
I just expect more from my dollar like you all and would love to see this great country back on it's feet.
Any rate I will check the pressure once the new gauge gets here.
I have been collecting all the parts to switch back to CPFI if this continues to fail.
If nothing else I have several of these engines that need a vehicle to reside in.
Thanks and if you have any more suggestions...I am glad to hear them.

Update:
I received the new actron gauge.Did some test's and boy did did things go screwy.
This gauge was registering around 10 psi but dropping like a rock.
Decided to use the T connector.Had to rig a plug at one end to test the fuel line alone.
Then I was getting 0.What the heck?
I had installed new lines all the way.When coming up through the frame I left some extra line and installed a compression fitting then the factory fuel line.
I thought that the compression fitting made be bad,couldn't find any leaks but why chance it?
I cut the fitting out then hooked up straight rubber fuel line to the tester.
Again ZERO psi.I was about to give up for the night when I thought about the gas gauge reading 1/4 of a tank.Wait...these things are notorious for running out of fuel at this point.
Guess what...I was out of gas.Thank GOD I was in the driveway.
Added fuel then primed it.Pressure went to 12 1/2 and stayed without dropping for about 5 minutes or more.Decided to move on.
The neat thing about this gauge is that it comes with a banjo fitting that screws into the back of the throttle body then you have to twist the fuel line around and screw it into the fitting.Now just hook up the rubber line and gauge.
10 psi then 0 now.
Gotta be the regulator even though I replaced it.
Took it apart...all good.
I finally installed one from a 350 v-8.
SAME as before.
I don't understand this.