Will not start unless primed?

Yep, you should hear the fuel pump in the tank when the key is turned on. here is how you can replace the fuel pump in the diagrams below. This is a generic guide below to show you what you are in for when doing the job. Also, have you run the codes?

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

and

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

Check out the diagrams (below). Please let us know what happens.

I installed the fuel pump, and I can hear it running when I turn the key on and stops. I then crank it and tries to start for a moment. Then it keeps cranking without start. I primed it twice and ran for a few seconds. What do you advise?

The problem with the engine not starting happened after I replaced the intake manifold gasket because of a vacuum leak. I had to remove several pieces of hardware from the intake manifold and I wonder if I didn't connect something correctly or damaged something.

Yep, that is what it sounds like there are ground wires that you need to make sure are connected to the engine. Were there any codes? We should check for spark as well.

This video will show you how:

https://youtu.be/baq_aEWNQ0Y

Let me know what happens.

Ground cables are okay. Strange that even when the car was running recently, I could not get any codes even when I pulled some sensor cables off on purpose. The engine still wants to start after some rest. Could the ECM be bad?

That was my next suggestion, here is the location and how to change it out. Disconnect the battery first.

After I installed the new fuel pump I could hear it priming each time I turned the key on. But since yesterday I can't hear it. I took the pump out and reinstalled. I still can't hear it priming. I ordered another pump which I will get tomorrow. If it turns out that the ECM is bad I will donate the car because it is too old to invest that kind of money in it.

Okay, you might be able to find a used ECM on Ebay. Also, I would change out the fuel pump relay again, it could be overloads from the bad pump. Here is how you can change the PCM out in the diagrams below. The ECM is plug and play.

I ordered a used ECM from eBay. Will update you after I install it.

sounds good.

I can't figure out how to access the ECM (how to remove dash parts).

This dash diagram should help. Check out the diagrams (below). Please let us know if you need anything else to get the problem fixed.

Just installed the ECM from eBay it cranks but doesn't start like before. I primed it a few times and it acts like it want to start but nothing.

I checked the new ECM before cranking and it had no codes. I tested it after a received no codes as well. Does it need to run for the ECM to show codes?

When the engine is cranking over does it sound normal? The engine does not need to run to show codes. Can you please shoot a quick video with your phone so I can hear the engine cranking it may have jumped time.

Video of engine cranking attached. It sounds normal. The engine does not show codes even if I disconnect some sensors. Could the new ECM be bad? How about a poorly installed crankcase position sensor?

Thanks for the video, did the engine do the same thing with the old ECM? it sounds like the ignition timing is way off. If the engine condition is the same lets install a new crankshaft position sensor. When you prime it and it starts does it run normally? Here is the location of the sensor. let me know please.

I installed a new crank case positions sensor and I wonder if I didn't do it right? The engine tries to start by priming, but it doesn't start. The cranking is the same as with the old ECM.

Let's remove the spark plugs to see what they look like please upload a picture of the plugs once removed.

https://www.2carpros.com/articles/how-to-change-spark-plugs

Please run down this guide and report back.

The spark plugs were installed with correct gap after the trouble getting the engine started. Like I said before the spark plug cables, coil, injectors, fuel pressure regulator, fuel and air filters, fuel pump, are new and were replaced after the engine would not start. The car has 150,000 miles and when it was running it started right away, no smoke and at high RPMs the engine didn't miss or backfire.

Since the spark plugs are out let's do a compression test.

https://www.2carpros.com/articles/how-to-test-engine-compression

Let me know.

Before I read your last post I checked the fuel pressure. This fuel rail doesn't have a banjo bolt to connect the gage so I used a T adapter that came with the gage. I connected one end to the fuel pressure gage and the other to the hose from the fuel filter. I connected the gage to the T. I had someone turn the key on several times to let the pump prime, but the gage registered 0. We cranked the engine and the gage read 45 lbs. for a few seconds then abruptly dropped to 15 Lbs. So it seems that the fuel pump is not working since I have a new fuel filter. Also, I noticed that the fuel gage shows almost empty when I have over one half tank. I checked all the fuses and found the one marked CIGAR was burned out. I replaced the fuse, but it didn't afect the fuel gage reading. I asume my next step is to work on the fuel pump and check the pressure again. I will deal with the compression test later. Your opinion?

I checked compression and thesew are the results:
#1 121 PSI
#2 120 PSI
#3 119 PSI
#4 122 PSI

I installed a new fuel pump and these are the results:
No start
I cannot hear the fuel pump run when priming
Fuel pressure 0
Tank has 3/4 of fuel
Fuel gage now doesn't move from empty with key on.
New relay checks OK
I cannot find a fuel pump fuse in the fuse boxes or in the schematics. Unless it has a different name. Is there one?

Next:
I will resinstall new pump and check connections. Also check power with meter and key on and resistance in floater.

Info: The problem started 4 years ago with high vibration. I changed all motor mounts and didn't help much. I took it to Pep Boys. 2 mechanics who worked on it said they couldn't fix it and after charging me $350 they said to take it to the dealiership. I decided to do it myself and so here I am at age 81 and retired corporate executive. I am in Phoenix and have been working in my garage with temps up to 112 degrees inside.

It's hot outside for sure, and you said it has a new fuel pump, but no fuel pressure and you can't hear it run. Can I ask the brand of the pump?

Sorry for the delay: After I ran a wire from the relay to the pump positive the pump works. How do I test the power and the negative cables from pump to relay?
The new ECM shows two codes: 1. P0340 Position sensor A circuit Bank 1 or single sensor. 2. P0102 Mass air volume air flow A circuit low?

I installed a new Camshaft position sensor, but I got no power. How do I trace the cables from the sensor to the ECM?

You mentioned checking the grounds, but I can't find a chart showing the grounds. I hope you guys can help me.