No Power To Fuel Pump.
I am puzzled-- Recently had the electric fuel pump replaced ( in the tank type). Drove it home, no problems. Parked in the yard and three weeks later went to start it and it would no fire. I tried sta...
Forum Discussion
When I had a problem with my 454 starving out under load or high speed(over 50) and everyone was saying that it had nothing to do with the fuel system that it was electrical, they were right. The fuel pump relay, an electrical devise, was bad. Thanks to the guys here I found the relay and finally found out how it was supposed to work. The aspirated engines need the in tank pump to supply fuel to the carb's fuel bowl for easier starting. After a few seconds, some say 3.5, some say 5 others 10 seconds, it doesn't really matter. After the prime is finished, and the engine starts, oil pressure closes a pressure switch and applies constant power to the in tank pump using the wire that the prime function uses.
TBI systems need higher fuel pressure but that is an easy thing to check and adjust. Because it appears your in tank pump isn't running, there isn't enough pressure to keep the engine running. In an aspirated engine the on block pump will keep the engine running but if the engine is running under heavy load it will starve out.
I believe that when the oil switch closes, a ground is applied to the relay coil and the armature closes. The 12v power for the pump is connected to the moving contact and when the relay activates the power then flows to the pump.
Because I usually have to work on stuff like that by myself, I use a piezo alarm instead of my DMM. I don't have to look at the alarm I can hear when power is applied to the alarm. Additionally I installed a "T" in the fuel line between the pressure regulator and the engine and ran a gas line up to the cabin so I could watch the fuel pressure. The big thing for me was using the alarm so I had my hands free to start the engine instead of trying to hold probes to the wires and the sockets. Often the fuel pump relays are faulty at least for my engine and the odds are that is your problem.
You know that the wire going back to the pump is good because the engine will start during the priming phase so you just need to check the oil pressure switch and the output of the relay after the prime phase and the oil pressure switch operates.
I think that I just kept googling different things until I got an answer. There are a lot of forums other than RV.Net and many of them are about engines and the 454 is a popular engine.
Good Luck
TBI systems need higher fuel pressure but that is an easy thing to check and adjust. Because it appears your in tank pump isn't running, there isn't enough pressure to keep the engine running. In an aspirated engine the on block pump will keep the engine running but if the engine is running under heavy load it will starve out.
I believe that when the oil switch closes, a ground is applied to the relay coil and the armature closes. The 12v power for the pump is connected to the moving contact and when the relay activates the power then flows to the pump.
Because I usually have to work on stuff like that by myself, I use a piezo alarm instead of my DMM. I don't have to look at the alarm I can hear when power is applied to the alarm. Additionally I installed a "T" in the fuel line between the pressure regulator and the engine and ran a gas line up to the cabin so I could watch the fuel pressure. The big thing for me was using the alarm so I had my hands free to start the engine instead of trying to hold probes to the wires and the sockets. Often the fuel pump relays are faulty at least for my engine and the odds are that is your problem.
You know that the wire going back to the pump is good because the engine will start during the priming phase so you just need to check the oil pressure switch and the output of the relay after the prime phase and the oil pressure switch operates.
I think that I just kept googling different things until I got an answer. There are a lot of forums other than RV.Net and many of them are about engines and the 454 is a popular engine.
Good Luck
