Re: I have 1989 f-150 4.9l 6 cly engine. The fuel pump...
Check the emergency fuel shut off switch it may be half set it is on the firewall by the clutch pedal reset it if that does not work it is a relay or a short in the pump it is not pushing enough pressure to keep it running
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
You have not mentioned whether you do a OBD fault code test on this, if not do that and post the results. Also jumper the fuel pump relay socket under the hood so it stays on all the time, you could have a defective starter switch, in this scenario the fuel pump is powered up as long as the engine is cranking, but as soon as the key is released to run position it shuts off.
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.
Find the fuel pump relay, connect across the contacts from B+ to the fuel pump. This will make the pump run continuously. see if the engine stays running. It may be a bad relay or a relay feed circuit which is also run the the auto shut down switch. Lee
You will need a new fuel pump relay to keep the engine running. The prime switch for the fuel pump operates fine for it starts the engine and once the oil pressure is up to snuff the computer shuts the prime switch off and turns on the fuel pump relay till you shut the engine off
Turn the key to the ON position without starting the engine. You should hear the fuel pump running for 5 seconds if working. This primes the gas to the injectors when doing this. If not heard running check the oil pressure switch for the 12 volts needed to run the fuel pump starts there on that harness. When the engine starts and the oil pressure reaches the normal pressure the computer shuts off that circuit and turns on the fuel pump relay to run the pump. The relay stays on till you shut the engine off
The fuel pump operates off two items upon starting the car. When you first turn the key to the ON position you can hear the fuel pump faintly running inside the fuel tank. If you can not hear it it seems it is working for you stated the engine starts then cuts off. That tells me the engines oil pressure switch is working the fuel pump. On the oil pressure switch this switch has a third wire which is directed to the fuel pump. When the engine reaches full oil pressure the computer shuts off the signal from the oil pressure switch and then the computer turns on the fuel pump relay which stays on until you shut the engine off. I do beleive the fuel pump relay is what you need for it is not working no longer. This will have many relays with the same part number on it. You can easily swap any relay that looks the same with the same numbers on it and try it once to see if the engine stays running.