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This sounds like a fuel system priming issue. When you first turn the key to the ON position (not cranking yet), you should hear a three-to-five second buzzing noise. This is the fuel pump running to pressurize the fuel system for cranking. This is controlled by the PCM and is relay activated. Once the vehicle starts and oil pressure rises, then the fuel pump is activated by the PCM via a different relay. If you can't start at first, what is probably happening is that the prime is not occurring and you have to crank it until the PCM sees oil pressure and then fires off the fuel pump. It could be PCM wiring or a bad fuel pump prime relay.
Your post is lacking any detail. However, if you are stating that the engine starts after being cranked but dies out (wont stay running) there are 2 ways the fuel pump is activated. When the key is first turned on, there is a 5 second fuel pump run (the ECM energizes the fuel pump relay). After the engine starts, the fuel pump relay will only stay energized when the oil pressure switch closes keeping the fuel pump relay on (oil pressure is above 5-7 psi). If the oil pressure switch is faulty or there is no oil pressure, the engine will stall just after starting.
The oil pressure sensor only keeps the pump running after the vehicle is started. If you turn key to on, the computer should signal to the fuel pump relay, turning the pump on for a couple of seconds to pressurize the fuel system. Then the computer signal stops. When the key is turned to start-cranking the engine- the computer again energizes the fuel pump relay, keeping the pump running until the engine starts.
If you have a voltmeter or test light, pull the relay out and check the relay terminals. One should be hot at all times-the power feed for the pump. The computer signal will be on the coil side of the relay-will have power for 2 or 3 seconds after key is turned to on. Or it will have a constant signal when the engine is cranking. If you can find both hot terminals at the relay, then start looking for a bad wire from relay to pump, or a bad ground for the pump, or a bad ground for the relay's coil side. Post back if unclear or other questions. When you pull the relay out, the diagram for it will be on the side of the relay-telling you which is the power feed and the terminal to the pump, and the coil side of relay, both the coil power side and the coil ground terminal.
My first question would be is the injector spraying when you crank it ? The way its supposed to work, the fuel line to the tank should have about 10psi of pressure before you crank the engine. When you turn the key on the pump gets power for 3 seconds to boost the pressure. The pump stops working until the engine has oil pressure which takes a few seconds. If the base fuel pressure leaks back to the tank, or the pump relay is not powering the pump, you won't have any fuel pressure or spray until you get oil pressure.
Could be the fuel pump relay, or a faulty pump, or pressure regulator. The fuel system is supposed to hold pressure after you turn the engine off. A faulty pump or pressure regulator could allow fuel to drain back into the tank overnight. You would need to crank the engine for several seconds to build pressure back up. The relay could be faulty and not giving the fuel pump power until the oil pressure comes up.
The pump relay is grounded by the computer, for 3 seconds when you crank the engine, and after the computer sees oil pressure or RPM. If the engine will not start the relay stops providing power after the first 3 seconds. You would check for the ground signal from the computer - most people either jumper the relay terminals or use another relay as a test.
Are you sure it's running when cranking? It should have come on when key turned on. This is for camrys up to year '91. It may apply in your '95, also. Check the 7.5 amp ignition fuse and the 15 amp EFI fuse and the EFI main relay, all located in the fuse box next to your battery. There is also the circuit opening relay tied in to fuel pump operation. It is usually found under center of dash. It is usually not the problem, but it is part of the checks for fuel pump operation. If your car has a " check connector" or "service connector" (also called a fuel pump check connector) under hood on driver's side near the firewall (a little 1 inch cube with a cap on it), then bridge terminals +B and Fp with a jumper wire. Turn key to on (don't start car). The pump should come on. Listen for fuel return noise from the fuel pressure regulator, and verify pressure in hose from the fuel filter. If nothing, check those fuses above. Here is how power runs to pump: Battery to 40 amp main fusible link-to 15 amp EFI fuse-to EFI main relay-to circuit opening relay-to fuel pump-to ground. Ignition switch and the computer (ECU) work the relays to pass power to pump. Hope this helps some, Randy. Good luck.
Fuel Pump Electrical Circuit OPERATION When the key is turned ON with out the engine running, the control module turns a fuel pump relay ON for two seconds. This builds up fuel pressure quickly. If the engine is not started within two seconds, the control module shuts the fuel pump OFF and waits until the engine starts. As soon as the engine is cranked, the control module turns the relay ON and runs the fuel pump. When the engine is cranking or running, the control module receives the Crankshaft Position (CKP) sensor reference pulses which in turn energize the fuel injectors. As a back-up system to the fuel pump relay, the fuel pump can also be turned ON by a fuel pump oil pressure switch. When the engine reaches about 28 kPa (4 psi), and the fuel pump relay does not complete the circuit, the fuel pump oil pressure switch will close to complete the circuit to run the fuel pump.
An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump oil pressure switch will turn ON the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi).
You can test to see if the relay it's self is bad by swapping it temporarily with another relay. If your truck has AC then that one should be compatible. Just compare the two to see if they're the same and if so, try using the AC's relay.
You need a new fuel pump relay. The engine fires up and runs off the oil pressure switch untill the oil pressure PSI is reached at normal operating conditions. When the oil pressure reaches its operating PSI the PCM or engines computer will shut off that circuit and turns on the fuel pump relay to run the fuel pump untill you shut the engine off
Generally when this happens all the time the fuel pump relay has gone bad. Upon starting any GM car up the fuel pump operates off the third wire on the oil pressure switch. When the oil pressure reaches operating pressure which happens in a few seconds the computer shuts off the current from the oil pressure sending unit and opens the circiut flow to the fuel pump relay. The relay will run ythe fuel pump until you shut the engine off. Replace the fuel pump relay and you shall have a good running car again