Starting issues

Sounds like a fuel management problem. The first thing to do would be to check the fuel pressure. The fuel pump may be failing.
The problem with electro-mechanical failures is that they slowly degrade or fail intermitantly.

Then if you have pressure, You might have failed or clogged fuel injectors. You may have a failed main relay which also acts as the fuel pump relay. Generally this can be found under the dash. I do not have schematics on its exact location. This is a good reason to get a service manual. Fuel delivery is most likely the issue. Does holding the throttle open without spraying starting fluid help at all?

Also look for any rotten or cracked vacuum lines around the fuel system.

To find the source of the problem, you will have to go through a process of elimination. Get the specification for the fuel pressure, which is probably 55 PSI, and test it. If you are going to test it yourself, a fuel pressure gauge can be purchased or borrowed from a parts store. You might try getting a service manual as it will help you locate the test port which will probably be on the fuell raill which is the part that the injectors are seated at one end and the other end of the injector seats in the engine block. Look for a small plug which should have an allen wrench reccess to remove it. Be very careful with removing it as the fuel pressure will be high if you have been cranking the engine over. Wait several hours before attempting this to allow pressure to drop. Still take caution.
Also, service mauals you get from parts stores are not like factory service mauals, which are very expensive, but are a good source for specifications, such as fuel pressure, and locations of parts, such as the pump relay and test port.
You can probably find even more information on diagnosis and instructions on how to perform tests on this site. There is a great deal of helpful information as far as that goes, but specifications for things like fuel pressure are not easy to find as they are propietary and you have to pay rights to use or publish them.
Let me know how it goes.

At least you know the relay is probably doing its' job if you can hear it. If you have a multi-meter, check for 12 volts or more at the leads that connect to the fuel pump.
The short period of buzzing is the pump priming the fuel system to start the Van. Normal.
I have had in tank pumps fail on me and something about putting electrical leads in a gas tank goes against my instinct. But, I have never had a problem. Spray a ton of WD40 or PB Blaster on the fuel tank straps as you will have to drop the tank.
Let me know how it goes.

I think you should check the fuel pressure. If you can hear fuel gurgling, the pump is probably trying to prime, but may not have adequate pressure.
First, try to go to a repair facility and get an OBD code reading to see if any error codes come up.
If not, performa a manual pressure test with a fuel pressure test gauge. Most Advance or chain auto stores have ones you can borrow with a deposit. There is a test port that I beleive is on the fuel rail. Also, double check th econnection of the fuel pulsator. This should be located where the fuel injector lines culminate.
Also, the oil pressure switch acts as a back up circuit and will cause problems. It can be tested by disconnecting the fuel pump relay and trying to start the van. If it starts it is okay, if not it needs replacement.
To test the fuel pump relay, do the opposite and connect the oil pressure switch and disconnect the pump realy. The engine will not even get that gurgling sound as it will not even try to prime the system. It can still be failing and not be providing 12 volts to the pump. To test his there is a red wire coming out of the pump relay. Apply battery voltage with jump wires. The hot wire or positive is the gren and white wire coming out of the relay and the ground is black and white. Check for continuity with an ohmeter. If the resitance is infinate, not continutiy, the pump realy is bad.
The fuel pump test connector is next to the fuel pump relay on the drivers side of the firewall.
The fuel pressure with the key in the on position should be, 60-66psi.
There is an in-line fuel filter. I am trying to find the location. That could be clogged.

See how this goes and get back to me.

That is fantastic. You swapped it out in 1.5 hours. That is really fast.
Isn't it a great feeling to turn that key and it runs! Nothing like working on your own stuff.
I am glad it worked out and rather quickly too.
More than that, I am glad to hear that you are very happy with the outcome.
Come back anytime and it is always a great feeling to help a customer get their vehicle running, so thank you for letting me know how it turned out because a lot of people don't bother to get back once its fixed.

Take care

Dr. C