94 F150 turns over but doesnt start
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Junior Member
Joined: Jul 2021
Posts: 2
94 F150 turns over but doesnt start
About a week ago my battery died and needed replacing so i replaced it. A few days later my battery light was coming on and my lights were getting real dim and then everything died on truck but i was still able to drive it home.I figured it was the alternator. I got it tested and it was bad so I replaced the alternator and now my truck wont start at all. I checked the fuel pump and its working fine. So i checked fuel line aft of the fuel regulator and no fuel came out when i depressed needle. So i replaced fuel regulator and it still doesnt start. also my battery is reading on the lower half.
Senior Member
Joined: Jun 2010
Posts: 16,615
Hi arcos10,
Maybe a little FYI might help here.
When you first turn the key on the ECM energized the EEC relay that provides the power to the fuel pump relay.contacts. The ECM ALSO provides a 2-3 second ground to energize the fuel pump relay. Before you even go to start the engine you usually can hear the fuel pump in the tank run for that 2-3 seconds. Can you check if you can at least hear that?
The fuel pressure regulator only maintains the correct pressure in the fuel rail IF,,,,,,,,the fuel pump is providing fuel under pressure.
It is important to know if the fuel pump is working at all.
Can we ask , how did you verify the fuel pump is working?
Maybe a little FYI might help here.
When you first turn the key on the ECM energized the EEC relay that provides the power to the fuel pump relay.contacts. The ECM ALSO provides a 2-3 second ground to energize the fuel pump relay. Before you even go to start the engine you usually can hear the fuel pump in the tank run for that 2-3 seconds. Can you check if you can at least hear that?
The fuel pressure regulator only maintains the correct pressure in the fuel rail IF,,,,,,,,the fuel pump is providing fuel under pressure.
It is important to know if the fuel pump is working at all.
Can we ask , how did you verify the fuel pump is working?
Last edited by hanky; Jul 8, 2021 at 03:59 PM.
Senior Member
Joined: Apr 2019
Posts: 1,236
You really need spark, compression, fuel and air in the proper proportions for the engine to run. The regulator is not going to cause a no pressure situation. You need to connect an actual fuel pressure gauge on the fuel rail. Pushing in the schrader valve or listing to the pump won't cut it.You need around 30-45 psi of pressure.10 psi will squirt out the schrader valve but won't run an engine. You could try squirting starting fluid in the throttle body and see if the engine tries to start. If the engine doesn't attempt to start, I would also check for spark.You also need a good battery to supply sufficient power to run all those systems. Charge it, test it, replace it and do whatever is required.
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