Help with no starting issue
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Junior User
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Help with no starting issue
Have a 97 f150 5.4. Car died on me a few times. tested the fuel pressure it was at the low number for the ok range. Always drove rough. Replaced the fuel pump with a junk yard one and the truck runs much better, But still has one issue. sometime after the truck has been running and the turned off (short trip to the store) when i go to started it again it will just crank and crank then start, or not start at all. After it stills for a little while it will start right up no problem. If people have any other questions ask away. Any help would be great.
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Junior User
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So i have fooled around with this truck a little more. Now the truck no longer starts. It just cranks and cranks, but never actually runs. Fuel pump never kicks on. tested the leads at the fuel pump replay and from what i can tell the leads that tell the replay to close and turn the fuel pump on don't have 12V across them. The wires that go to the fuel pump appear to. I took a short piece of wire and jumped the fuel pump relay and could hear the fuel pump running. had the fuel pressure tester on and it was at 40lbs. tried to start the truck with the jumper in place and nothing. I could use all the help i could get right now. is there a way to see if the COP are firing when trying to start?
Lead Driver
Joined: Sep 2006
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You need a little basic understanding of how the overall system works or you will flounder around.
Upon ignition turn-on, the fuel pump is supposed to run for about 1 to 2 seconds. Does this happen?
As cranking begins, the crank sensor sends rotation data to the computer that begins the fire order timing and restarts the fuel pump..
The cam position sensor signals the computer the correct time to inject fuel.
So a no start needs to look at these items.
Plugups, fuse, relay failure etc.
Good luck.
Upon ignition turn-on, the fuel pump is supposed to run for about 1 to 2 seconds. Does this happen?
As cranking begins, the crank sensor sends rotation data to the computer that begins the fire order timing and restarts the fuel pump..
The cam position sensor signals the computer the correct time to inject fuel.
So a no start needs to look at these items.
Plugups, fuse, relay failure etc.
Good luck.
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no fuel pump prime. It does nothing. From looking at my haynes manual it seems that with the key in the ON/RUN position if i remove the cam position sensor plug that it should have 12 volts to it. I took it off and there was no volts. I tried to test it on my other working truck, but the coil packs are in the way. I honestly think it has a bad PCM. when i try to read codes it can't connect.
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Lead Driver
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Check fuses under the dash first then in the engine bay power dist box.
Scanner is supplied 12 volts from a pin in the test connector. There is a seperate fuse for it and it is shared with some other functions that could blow it.
A user manuel should tell you what locations all are at.
The cam sensor has power applied but pulses a signal to the PCM according to cam rotation spot on the front of the cam drive gear.
It only provides injector timing in relation to valve opening.
If there is no main power, nothing gets power and nothing happens.
Good luck.
Scanner is supplied 12 volts from a pin in the test connector. There is a seperate fuse for it and it is shared with some other functions that could blow it.
A user manuel should tell you what locations all are at.
The cam sensor has power applied but pulses a signal to the PCM according to cam rotation spot on the front of the cam drive gear.
It only provides injector timing in relation to valve opening.
If there is no main power, nothing gets power and nothing happens.
Good luck.
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