Uncontrollable coil spark
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Joined: Apr 2017
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Uncontrollable coil spark
With key on engine off my coil with start sending spark to plugs like crazy for a minute and then turn fuel pump and injectors on then it would stop after a minute What Would be a good place to start, the pip sensor, TFI Module, coil. Iv did some test and I get spark from turning the distributor manually to see but it won’t start. How does this ignition system work in the 93 f150. It’s hard to diagnose something without throwing parts at it thank you for the help I appreciate it
Fleet Owner
Joined: Oct 2005
Posts: 20,786
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From: Kentucky
I assume this means the fuel pump is running for a minute then shuts off?
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
Given the symptoms I would lean towards a bad computer (PCM). While the typical failure mode is the fuel pump energizing whenever the key is in the Run position, there are many others. Remove the PCM then open it up to look for signs of leaking capacitors
Another quick troubleshooting step is remove the connector from the PCM then turn the key to the Run position. If the continuous sparking remains you could have a bad PIP or TFI. At least now you have eliminated the PCM as the cause.Regardless of the testing outcome continue on to removing the computer for an inspection as a preventive measure.
In the above testing scenario remove the negative battery cable before removing or installing the PCM connector. Once the connector is removed you can temporarily re-install the battery cable.
Another quick troubleshooting step is remove the connector from the PCM then turn the key to the Run position. If the continuous sparking remains you could have a bad PIP or TFI. At least now you have eliminated the PCM as the cause.Regardless of the testing outcome continue on to removing the computer for an inspection as a preventive measure.
In the above testing scenario remove the negative battery cable before removing or installing the PCM connector. Once the connector is removed you can temporarily re-install the battery cable.
Thread Starter
|
New User
Joined: Apr 2017
Posts: 14
Likes: 0
Given the symptoms I would lean towards a bad computer (PCM). While the typical failure mode is the fuel pump energizing whenever the key is in the Run position, there are many others. Remove the PCM then open it up to look for signs of leaking capacitors
Another quick troubleshooting step is remove the connector from the PCM then turn the key to the Run position. If the continuous sparking remains you could have a bad PIP or TFI. At least now you have eliminated the PCM as the cause.Regardless of the testing outcome continue on to removing the computer for an inspection as a preventive measure.
In the above testing scenario remove the negative battery cable before removing or installing the PCM connector. Once the connector is removed you can temporarily re-install the battery cable.
Another quick troubleshooting step is remove the connector from the PCM then turn the key to the Run position. If the continuous sparking remains you could have a bad PIP or TFI. At least now you have eliminated the PCM as the cause.Regardless of the testing outcome continue on to removing the computer for an inspection as a preventive measure.
In the above testing scenario remove the negative battery cable before removing or installing the PCM connector. Once the connector is removed you can temporarily re-install the battery cable.
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