My expedition has been running well, Replaced the #5 coil a few weeks ago, and a few years ago I replaced them all with some from e-bay.

Today it was coming home from town and bam...

P03051,52,53,57.
4 COP at one time?

There were also 172, and 175. But those are fuel mix, and I cleared those, assumed they were because of the above 4 cylinders.

Where do I go from here.

 

I replaced one coil, and seems it got better, I am down to just a #2 misfire. Swapped that COP with the new one on #1, and still has misfire on #2. Pulled the plug and it looks ok, but the gap was about .065 so I closed it to about .052.
Still have the misfire. only on #2.

Where do I go next?

 

First try a new spark plug. Just because it looks good doesn't mean it is. After that, you'd have to look at possibly a bad injector.

 

I went and got a new plug, and a spark testing jig thing... Anyway, I am getting no spark. The 12V is always there, but the other wire is not sending the signal to fire the COP.
So I am guessing a broken wire, but I do not know where to look, Anyone got a diagram on line? I have a book for the older Superduties/excursion. But they do not show this wiring, so I do not think the correct one would either.

 

I have now traced the wire bundle up to a plug on the firewall. ohm'd the wire and it appears that it is good.
So now where? Am I in need of a module that this plugs into? if so what is it called? everything else is working, except this one injector, as far as I know.

This began with multiple and is now down to one, and I did not really do a lot.
If this is the case, would that also cause it to be hard to start?

Should I take this to Ford? is there anything on the other side of that module which would affect only one injector?

Sorry for all the posts...

 

will a bad injector cause the PCM to cause the coil to not spark?

Any other ideas?

 

No it will only keep fuel from being sprayed into the intake port. As to your no negative pulse to the coil issue, even though the wire ohms out okay, the connector might not be making a good connection.

 

This is where I am now,
I ohm'ed the two col wires at the coil together and got 1.2ohms. The rest were open, as expected.
So I decided that the wires were shorted together somewhere, and pulled a bunch of coverings and separated the wires all the way back to the #3 coil. Still the same,
So then I unplugged the connector from the pcm, and it went open.

So then I plugged the PCM in and started it up, (new plug also) and still no fire. Pulled the cover for the connector, and took my test light to the wires at the pcm.
The power line is flashing as expected, as are the signal wires for 1,3,4. But 2 signal is steady. I know not a perfect test because of the delay in the light, but I can see it pulsing on all of them except #2.
So if I am understanding this correctly, the power comes out of the pcm and goes to all the coils, then the pcm grounds the coil to fire it. And this is not happening at #2. it always has 12V. good thoughts? leads me back to the pcm? if I am getting the 12V back to the PCM that eliminated the connection at the coil, correct?

I have an appointment at ford, but at this point I can buy a used PCM for about the same cost. What should I do next?

Thanks for helping me on this!

 

If it were me I'd try the used PCM first. If that's not the problem you can always resell it on eBay and you're out no money.

 

I think I will see if I can find one locally today. A friend of mine (in another state) works for ford and says that he has never seen a pcm cause a miss-fire, and I trust him. But there is always a first...

 

I admit that I am having trouble following your terminology, ("ohm'd two wires together"?, or "the power line is flashing"?, but that's just me, so don't take it personally.

Here's how it works. The coils recieve VPWR (aka vehicle power, or battery voltage) on the red w/green stripe wire, (which is "common" to all the coils) when the ignition key is in the ON or START position.

The PCM supplies the ground to each coils circuit (via the "uncommon" colored wire at each coil to energize the coil, providing the proper amount of coil dwell, and "ungrounds" the coil when it is time for the coil to fire the sparkplug.

So if you are using an unpowered test light and are back probing the coil connectors, the test light will light when the coil circuit is off, and the test light will turn off (or go dim) when the coil is energized.

Now if the test light stays on bright when on #2's coil circuit with the engine running, that coil circuit is not being pulled to ground by the PCM. The PCM may be bad, but if that pink w/white stripe wire is open, or shorted to VPWR some where in the vehicle's harness, or does not have a solid connection at the PCM connector it will not be pulled to ground.

Check for a spread pin or green crud (trademark ) on the pin #1 of the PCM connector. With the PCM connector unpluged and the #2 coil unpluged, ohm out that pink w/white wire from pin #1 on the PCM connector to the harness side of the #2 coil connector. Should be less than 5 ohms.

Also, with the PCM and #2 coil unpluged, use your volt meter to see if there is any voltage on that pink w/white stripe wire and ground. Should be none.

By "no fire" do you mean the sparkplug didn't fire, or the engine still shakes like a misfire. As alloro indicated, you may have a bad injector, or low compression on cylinder #2. Pull that coil off and insert a sparkplug into the coil, ground the sparkplug, and see if there is any spark occuring.

 

sorry about all of the terminology issues,
If I have the coil unplugged, there is no power on the pink/white wire. It ohm's 1.2 from the PCM to the coil. the red/green wire have 12V.

By no fire I mean there is no spark at #2. But the engine runs. When I rev it it seems like more than a single cylinder miss, but that is the only code I still get.

And that wire does not pulse when the engine is running, so It is looking more and more like the PCM. And the inside of the connectors are clean, and you can see where they contact each other when being plugged in, and unplugged.

Can I change it? From a wrecking yard? or programmed for my vehicle?
Is it integrated with the factory passive theft system? And how do I know if my car has that or not? or does it matter?


Thanks again for the help.

 

You'll need a super smart scan tool. It has to be able to off load the software in your PCM into the scan tool. Then pull your PCM, install the replacement PCM, and then dump the software from the scan tool into the replacement PCM. Might be better off finding a shop that has been there and done that.

 

If I install one like this will I still have that issue, Or will they reset it for me before they ship it? Then can I program it to the two keys I now have? or you they have to do it?

2003 Ford Expedition ECM/PCM

Thanks again..

 

Well, got confirmation from the dealer. Bad PCM. $1300.00 to fix it.... Ouch!