10thGenScab

If you had to smack the dash, could there be an issue with PATS? Might be a broken solder trace or two back there in the cluster.

white89gt

I did not see that. It looks like maybe it was added after I replied.... but you are absolutely correct 10th Gen. It could very well be some bad solder joints.

10thGenScab

I concur with your in-depth thread forensics.

FordmanUGA

Nope, just drove it on the road. No potholes or bad bumps. The only thing I can think of was when I smacked the dash the other day to get the odometer to come on, but I don't know of anything behind the dash that would cause it to not get spark when I crank it. I'm wonder if the ECM just died. I've gone as far as I can with it I guess, I'll probably get it towed to a mechanic in the next month or so.

FordmanUGA

I'll get someone to check it. I'm done working on it, lol. All electrical issues do is raise my blood pressure.

I had to work on electronics in the Marine Corps and I hated it.

One thing I didn't think of though, if the PATS was malfunctioning wouldn't the light be blinking really fast? It's burning steady when I turn the key to auxiliary.

FordmanUGA

Well, I said I'm done but I went ahead and checked the PATS. If I'm correct the PATS is checking out as I have a steady burning Theft light that goes out after it checks out my key. From what I've seen and read on the PATS if there was a malfunction in the PATS the light would blink very quickly and not stop. I'm stumped.

River1

From the diagnostics manual: With the key on, engine off (KOEO) check the voltage between pin 13 on the data link connector and the battery negative post. Ensure battery is fully charged. Is the voltage greater than 9 volts? If yes, you have a short to power. If not, check PCM driver to coils. Use incandescent test lamp between B+ and each coil driver at the circuit connector. Crank Engine. Does the light blink consistently and brightly for each revolution? Next depends on the answer.
EDIT, B+ is at the power relay harness connector. You will probably need the wiring diagrams for this.

FordmanUGA

Thanks, I'll probably just take it in to my mech. I have no way of checking all of that, lol. I worked on electronics on comm gear, once I got out I've had zero interest in it.

Jbrew

Winner! Well it's the next step for the OP anyway, should of been done already...regardless ,-

Yes, PCM coil signal ground needs verifying. For the DoItYourselfer it's quite easy. For coils, you use a test light that will activate at 6V vs 12V. That said, most 12V lamps will indeed pick-up a 6V signal. However, the lamp will blink weak. Weak is okay as long as it will blink visibly at 6V's. FYI, - every noid light I've used in the past will indeed pick up 6V signal, the noid is my go-to for coils.

Precaution going in: - You have to be careful with Ford connectors(terminal end). Meaning DO NOT jam/force ill fitting probes into them...you can bend the terminal ends inside the connector very easily. That's a time consuming fix no one wants to deal with (w/o further explanation). So yea, special attention here, - Don't do that! In other words, just be careful probing the connector. Using the correct size probe is best. You can also probe from behind the connector through the silicon seal OR use a pin clamp on the wires. Pin clamps work very well for this procedure since a very fine pin will suffice. Another very good reason to use that type of clamp is because the insulation will self seal negating the possibility of future corrosion issues. A little long on the explano here, but it should help.

Testing, test goes much quicker with auxiliary starter gun (they are cheap in price) connected up to the starter relay on the firewall. This isn't critical if you can position the noid or TL so that you can see it from the drivers seat. From there it's just a matter of connection up the each coil pigtail and cranking the ignition. PCM coil signal will illuminate promptly as long as the solid state switches within the PCM's PCB are not fried. If there is no action from the noid or TL, check connections and move onto the next.

In most cases when you have signal ground issues, 4 coils will be affected, not just one or two. It's usually 4 or all 8. While checking coil signal, I will usually confirm injector signal as well. Tow birds with but one stone thing. FYI, -Injector signals are higher in voltage. The noid/TL will illuminate brighter vs coil signal. No big deal.

No 1 reason for blown coil signal from the PCM, = Failing to disconnect the battery before working under the hood. (Accidental battery short can take the PCM switches out. This is due to the multiple grounds in the vehicle that rout directly and indirectly to the PCM. Always disconnect the battery)

No 2 reason, = Welding on a vehicle without a PCM hard disconnect first.

Good luck, it's easier to test this out than it sounds. No experience required, it's all in the post.

BTW- If you take it in, tell them you have not verified signal ground yet. It will help a little.

FordmanUGA

Thanks JBrew and River1. I haven't done any work on it, just drove it shut it off and then it wouldn't start. The last work done on this truck was a year ago when Ford out the new block in. It just randomly won't crank. All I've done so far is verify that the fuel delivery isn't the issue and swapped out the crankshaft position sensor, and yes the batt was disconnected when I changed out the sensor. I'll let the mechanic know I haven't verified the ground.