WHY ENGINE DOES NOT FIRE?

  • Tiny
  • Stokes
  • 1999 Ford F-150
  • 205,000 miles

Initially the vehicle began not to start. So I changed the crank sensor and there were no problems for approximately 3 wks. Then the problem began again. So I changed the crank sensor again with no results. I then pulled a spark wire, no fire going from the coil pack. Checked the connector leading into the coil pack again no fire.

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Saturday, April 28th, 2012 AT 1:52 PM

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  • Tiny
  • ASEMaster6371
  • Expert
  • 25,556 posts

Did youcheck for fuel pressure?

Roy

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Saturday, April 28th, 2012 AT 1:56 PM
  • Tiny
  • Stokes
  • Member

Yes. There is little or no fuel pressure but there is no fire going to the fuel pump>>>There is just no fire. I have disconnected clean/sprayed the main harness on the firewall with no positive results.

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Saturday, April 28th, 2012 AT 5:15 PM
  • Tiny
  • ASEMaster6371
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  • 25,556 posts

When you turn the key on, it will activate the pump for only 2 seconds. After that, it will turn on when the motor starts.

Check the interia switch behind the right lower kick panel especially if had it towed.

Roy

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Saturday, April 28th, 2012 AT 5:18 PM
  • Tiny
  • Stokes
  • Member

Thanks>>>Have not been towed>>>But would the fuel pump being inoperable prevent getting fire at the coil and spark wires?

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Saturday, April 28th, 2012 AT 5:24 PM
  • Tiny
  • ASEMaster6371
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Which motor do you have?

Did you crank it long enough with a good ground on the plug to check it?

Roy

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Saturday, April 28th, 2012 AT 5:27 PM
  • Tiny
  • Stokes
  • Member

The vehicle has a 4.6 engine and yes to the length of cranks.

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Saturday, April 28th, 2012 AT 5:37 PM
  • Tiny
  • ASEMaster6371
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It is rare for a no spark condition on the 4.6/5.4 series.

I would verify fuel pressure first with a gauge.

Roy

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Saturday, April 28th, 2012 AT 5:46 PM
  • Tiny
  • Stokes
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But there is NO spark, so what else? Could it be the cam sensor?

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Saturday, April 28th, 2012 AT 10:04 PM
  • Tiny
  • ASEMaster6371
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Yes, it could but it would throw a code if it was. Is there any codes? If not, I am still going to refer back to fuel pressure as it is the first check in a diag after compression test.

Roy

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Saturday, April 28th, 2012 AT 10:10 PM
  • Tiny
  • Stokes
  • Member

Nothing is showing up on the codemachine. However I did put a live wire from a battery directly to the fuel pump wire leading to the fuel pump and did not hear the pump engage. If the pump is working would that generate fire/spark?
But my unlining question is why isnt there's fire from the coil and leading into the coil? Even if there is fuel would the vehicle start w/o spark? I am very thankful in your help>>>>Semper FI

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Saturday, April 28th, 2012 AT 10:21 PM

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