New utilitec pump cuts on and off, won't hold pressure

Have you done a new fuel pump.

Just to confirm that the pressure tank was pre-charged with the tank emptied of water. If water comes out of the air valve, then the bladder is ruptured, and the tank needs to be replaced.

As the pressure TANK only holds the liquid under pressure, you now have two good tanks.

Did you adjust the pressure switch or check it for operation?

Either adjust it or change it with a known good one.

Check your Safety Valve. It is on the back of the tank sometimes on one of the pressure switch ports or on the air manifold. It has a ring on it to pull to relieve pressure from the tank. The spring in these can get overheated so they don't hold air unless the tank gets over 165 psi. When the motor is running hold the center pin in to see if you have the same results. If the valve holds air until you let it go, replace it.

Think the oil pressure switch keeps the fuel pump running once started. Suggest replacing Oil pressure switch. And no it won't effect oil pressure reading when it goes bad. The switch is a safety device. When you roll it over and the oil pressure drops the switch cuts off the fuel pump. Neat huh? Need some good feedback Thanks!

There are several causes for this to occur.
1. If it is a 20-40 switch right out of the box it may not be set correctly. I have had this happen. If it builds to 30psi and shuts right off without straining to build to 40psi adjust the Cut-Out pressure up to 40psi. There are two different adjustments on a well switch. One for Cut In / Cut Out psi and one for Cut Out psi.
2. Lack of head pressure being built by the pump can be the cause. This can be attributed to the wrong Jetting in the pump. IE: A shallow well jet/venturi on a deep well.
3. The pump may have a bad impeller, but the pump will generally really strain to build pressure and a bad impeller will be loud, like grinding at times.
4. Double check the pre-set pressure in bladder tank also.
RJ

sounds like its not working properly, the fuel pump pumps or it does't, then goes to regulator this is where pressure is adjusted. check fuel pressure with gauge, sometimes even new fuel pumps don't pump enough fuel. most fuel injected cars have over 50 pounds pressure.

There are two valves in play here. There is a relief valve that opens when the motor kicks off to release the pressure in the compressor itself. That is normal, and is required so that the motor can restart next time without having to overcome that pressure. The other valve is the problem. It is a reed valve between the compressor and the tank. This valve's job is to prevent the air in the tank from returning to the compressor. Think of it as a ratchet for the air. It is this reed valve that has failed.

I would check the holding tank pressure, if you have one with a bladder. Turn electric off to the pump, and drain all water from the tank. Take a tire pressure gauge and check the tank pressure at the air valve on top of the tank. That pressure should be two lbs less than your cut-on pressure. If the cut-on pressure is 20 lbs, then the tank pressure should be at 18 lbs. If there's too much pressure in the tank, it wont let the pressure switch work correctly. If you get water from that air valve, then the bladder is ruptured, and a new tank is needed.
I hope this works for you!