Mechanics

WHY ENGINE DOES NOT FIRE?

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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Stokes
April 28, 2012.



Did youcheck for fuel pressure?

Roy

ASEMaster6371
Apr 28, 2012.
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.

Tiny
Stokes
Apr 28, 2012.
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

ASEMaster6371
Apr 28, 2012.
Thanks>>>Have not been towed>>>But would the fuel pump being inoperable prevent getting fire at the coil and spark wires?

Tiny
Stokes
Apr 28, 2012.
Which motor do you have?

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

Roy

ASEMaster6371
Apr 28, 2012.
The vehicle has a 4.6 engine and yes to the length of cranks.

Tiny
Stokes
Apr 28, 2012.
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

ASEMaster6371
Apr 28, 2012.
But there is NO spark, so what else? Could it be the cam sensor?

Tiny
Stokes
Apr 28, 2012.
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

ASEMaster6371
Apr 28, 2012.
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

Tiny
Stokes
Apr 28, 2012.
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