no start.
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Freshman User
Joined: Jun 2014
Posts: 32
Likes: 0
From: Stationed in ND
ok so that sends a signal to the pcm? so if the pickup was bad than it would be tricking the pcm to think that it needed fuel when it actually doesn't? is there anyway to rule out the pickup sensor? what we were going to do if it had a crankshaft sensor was just disconnect it and see what the results were. im leaning towards pcm BUT dont want to jump to that conclusion.
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Freshman User
Joined: Jun 2014
Posts: 32
Likes: 0
From: Stationed in ND
we tested the TFI module, we tested the coil pack and also changed it with a good one just because i had one laying around. tomorrow im going to inspect the ignition. one of the last few times we tried to crank it the fuel pump stayed on for about 10 sec with the key completely removed from the ignition. so were going to look into that, if that shows no results than on to the PCM. hopefully thats not it though...got some results so happy for now...
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
The fuel pump relay is energized by the PCM (aka EEC). It supplies a ground when the PCM logic is satisfied. The supply voltage comes from the PCM (aka EEC) power relay. That is energized by the key/ignition switch.
For reference:
Page 1
Page 2
In order for the fuel pump relay to stay energized with the key out is a stuck PCM (aka EEC) relay, a faulty ignition actuator, or a short to a power source AND the fuel pump relay receiving a ground.
Perhaps two issues are going on here. Those relay sockets are known to corrode so it may be worth a shot to also inspect those too. That would not explain why the injectors are always on, that is either a faulty PCM (very weird failure mode) or perhaps more wire integrity issues.
For reference:
Page 1
Page 2
In order for the fuel pump relay to stay energized with the key out is a stuck PCM (aka EEC) relay, a faulty ignition actuator, or a short to a power source AND the fuel pump relay receiving a ground.
Perhaps two issues are going on here. Those relay sockets are known to corrode so it may be worth a shot to also inspect those too. That would not explain why the injectors are always on, that is either a faulty PCM (very weird failure mode) or perhaps more wire integrity issues.
Thread Starter
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Freshman User
Joined: Jun 2014
Posts: 32
Likes: 0
From: Stationed in ND
Rla:
We inspected the relay sockets because I know they are known to corrode. The only reason I'm leaning for the ignition system is the fact that the fuel pump kept running with the key out. I'm trying to search the interwebs and see what's all behind there as far as switches go. I don't think it's as easy as it being the ignition tumbler. My truck does have tilt steering wheel and I've read that sometimes the tilt wheel messing up the wires/switch. Just an FYI we have switched relays for the EEC and cleaned those connectors. Were going to dig into the ignition actuator today. Last night when we were turning the key to run (but not starting) we had several times where the injectors would not continue to fire...(what we want) this was of course after giggling the ignition switch and messing with the tilt wheel. Well be digging into it here after a bit. At work right now.
Thanks again guys for all by our input!! I'm getting closer, finally!!! after messing with it for months
Rick
We inspected the relay sockets because I know they are known to corrode. The only reason I'm leaning for the ignition system is the fact that the fuel pump kept running with the key out. I'm trying to search the interwebs and see what's all behind there as far as switches go. I don't think it's as easy as it being the ignition tumbler. My truck does have tilt steering wheel and I've read that sometimes the tilt wheel messing up the wires/switch. Just an FYI we have switched relays for the EEC and cleaned those connectors. Were going to dig into the ignition actuator today. Last night when we were turning the key to run (but not starting) we had several times where the injectors would not continue to fire...(what we want) this was of course after giggling the ignition switch and messing with the tilt wheel. Well be digging into it here after a bit. At work right now.
Thanks again guys for all by our input!! I'm getting closer, finally!!! after messing with it for months
Rick
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Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
It kinda also sounds like the PCM Computer maybe reinitializing.
You can google for Ford Computer reinitializing and there is some information on it.
This can be caused by a power wire shorting to a sensor wire.
Very hard to find the problem if this is the case.
I fought one of these a long time before I found the short in the starter harness going to the O2 sensor.
You can google for Ford Computer reinitializing and there is some information on it.
This can be caused by a power wire shorting to a sensor wire.
Very hard to find the problem if this is the case.
I fought one of these a long time before I found the short in the starter harness going to the O2 sensor.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
It kinda also sounds like the PCM Computer maybe reinitializing.
You can google for Ford Computer reinitializing and there is some information on it.
This can be caused by a power wire shorting to a sensor wire.
Very hard to find the problem if this is the case.
I fought one of these a long time before I found the short in the starter harness going to the O2 sensor.
You can google for Ford Computer reinitializing and there is some information on it.
This can be caused by a power wire shorting to a sensor wire.
Very hard to find the problem if this is the case.
I fought one of these a long time before I found the short in the starter harness going to the O2 sensor.
