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Cylinder 1 misfire, On start up or <1000 rpm

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#22 ·
Ford service manual. Must be the exact car, they move those pinouts all over the place. Wrong power into one and kiss PCM goodbye. In fact, it's bad practice to send ANY power into PCM, it gets broken out to check so no damage.
 
Discussion starter · #23 ·
I Have been searching for the last few days, no luck. Is there any archives through this forum? Someone has to know where these diagrams are on here I would imagine. My other theory is that there could be some kind of inline backup fuse after the power diode somewhere in the car? This could be wrong I was just wondering.

Any leads on the PCM and ECU diagrams would be awesome!
 
#26 ·
Might be more useful:
Image


Off the negative battery post, black, black/orange, black/blue wires should all be checked for cleanliness/tightness/integrity.
If you pm me, I can send more complete diagrams if these aren't enough.
 
Discussion starter · #27 ·
Thanks to BC_ZX3 and some luck, I was actually able to get all three of those ground lines to the PCM continuity tested straight to the ground terminal of the battery. I just ran my meter straight to it, can't say I was expecting it to work but it did.

What other situations would cause the odometer dashes?
 
#28 ·
Suppose you're back to the power side of it, responded that you had power at the diode before and that the diode was working correctly - next step is to see if it gets to the PCM connector.

Still no start no run, correct?

Have you checked for key on power at the coil connectors?
 
Discussion starter · #29 ·
I did try and measure to see if I get key on power at the pcm, but I didn't have a good way of getting the probe in the connector hole. I have not checked for key on coil power, I will!

And yes still a no crank situation
 
#30 ·
One possibility I can't confirm offhand is communication with the Instrument cluster, that's next on the list for the dashes situation assuming the PCM powers up.

At some point they went to using that as well for the PATS memory, not sure of the change over time. MkII or some time in the Mk1.5 version (yours is year 1 Mk1.5, with some differences from the '06-'07).
 
Discussion starter · #31 ·
Okay so I just unplugged a coil and checked for voltage from both pins to ground of the battery because I didn't know which pin was which, but I found that one pin shows battery voltage with the key off and then it drops to about 11.6 volts with the key in the on position.
 
#32 ·
Voltage will always drop with key on, getting power to the coils proves the fuse for engine power is good (not blown by an RF capacitor wire to ground).
 
Discussion starter · #33 ·
This isn't looking good, what are the chances its a real problem with the pcm? Another theory I had, considering it happened once before is that I guess what is basically a clutch pedal position sensor went bad. Same thing happened, no crank no start and dashes on the odometer. I pulled the sensor today and it tested continuous when I plugged it in, but there was another button on the back that I didn't know what its function was. Is there a better way to test this sensor?
 
#34 ·
Which sensor?

There's a position sensor for fully depressed that's just a two wire for starting safety switch, and one at the top to cut the cruise control when pedal is depressed any and report to the PCM as well.

Don't give up yet, since you mentioned time to play with it. Paying someone to do the same things, or toss expensive parts at it THEN do the same things if that doesn't fix it can get pricey.
 
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