P0307 fault
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P0307 fault
I have a 2001 King Ranch F150, which has a 2004 Lincoln Navigator 5.4 DOHC Intech engine installed. The engine was installed in 2005 and had less that 100 miles on it. The engine now has approximately 95000 miles and I have recently got the P0307 fault-miss fire on # 7 cylinder. I have installed a new spark plug, COP, and fuel injector. The fault has returned. Has anyone have any clues to the cause of my problem?
Lead Driver
Joined: Sep 2006
Posts: 7,907
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The 307 is specific to those parts you replaced for cylinder 7.
Could be a faulty coil.
Check for a heater hose leak over the top of that cylinder
There is no guarantee any part won't fail at any time.
I would change the coil again and be sure grease is used on the boot tip and inside the tip to be sure the boot slips onto the plug when stalled.
Good luck.
Could be a faulty coil.
Check for a heater hose leak over the top of that cylinder
There is no guarantee any part won't fail at any time.
I would change the coil again and be sure grease is used on the boot tip and inside the tip to be sure the boot slips onto the plug when stalled.
Good luck.
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Joined: May 2013
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P0307 error
Thanks for the spread, but I have checked the cylinder compression and it is good. The cylinder was dry and spark plug clean and showed no signs of fouling. Going to use a noid light to determine if there is voltage at the injector plug.
Lead Driver
Joined: Sep 2006
Posts: 7,907
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Well no, the injector gets a ground from the PCM to operate the injector to inject fuel while the intake valve is open.
The coil gets a ground from the PCM to magnetically saturate the coil then opens the circuit to fire the coil spark at the right number if degrees before top center on compression stroke.
If the injector 'circuit' has a fault you should see either a code 207 or a code 279.
Since you see a code 307 it seem it would be a faulty coil on it's 'secondary' side or loss of fuel in some manner such as a plugged injector or low compression.
.
Voltage is common to all injectors and coils from the 'same' fused source.
As you can see they don't all work at the same time. One at a time and offset in time single file.
How the PCM knows it is in this area is it measures crank rotation time from the front crank sensor for each cylinder in the fire order every time and keeps a record.
The camshaft sensor reference times the fuel injection.
When any cylinder rotation time falls below the 'running' average for all cylinders the code is set for that cylinder.
Pretty clever achievement from software and sensor inputs..
.
I don't know what you will find eventually but this will help you understand how the operation works.
Good luck.
The coil gets a ground from the PCM to magnetically saturate the coil then opens the circuit to fire the coil spark at the right number if degrees before top center on compression stroke.
If the injector 'circuit' has a fault you should see either a code 207 or a code 279.
Since you see a code 307 it seem it would be a faulty coil on it's 'secondary' side or loss of fuel in some manner such as a plugged injector or low compression.
.
Voltage is common to all injectors and coils from the 'same' fused source.
As you can see they don't all work at the same time. One at a time and offset in time single file.
How the PCM knows it is in this area is it measures crank rotation time from the front crank sensor for each cylinder in the fire order every time and keeps a record.
The camshaft sensor reference times the fuel injection.
When any cylinder rotation time falls below the 'running' average for all cylinders the code is set for that cylinder.
Pretty clever achievement from software and sensor inputs..
.
I don't know what you will find eventually but this will help you understand how the operation works.
Good luck.
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