I'm new on the site and this is my first time ever posting on a forum so bear with me lol.


I'll try my best to organize all the info on what I've done to the truck so far and all of my findings.


About 3 months ago i was driving down the highway when i suddenly had a significant loss in engine power, I'd hit the accelerator and the truck would hardly move, and the engine started vibrating really bad. I got the truck towed home and checked for codes and got p0351 p0352 p0353 p0357. Over the last 3 months I've been messing with it here and there when i can but no luck. The truck was running great before all of this took place, i had no real issues. This truck isn't my daily driver. Me and my wife just use it for trash and moving stuff. It's been in my family since 04 and has always been taken care of.

The truck will start and idle roughly but it's hardly drivable.

I replaced all 8 of the COPs and spark plugs with just some midrange COPs and motorcraft spark plugs.


I replaced all fuses, relays and diodes related to pcm, coils, and injectors.


I checked the entire engine wire harness and found no damage of any kind. No breaks, no rubbing, and no melting. I checked the wiring that leads to the pcm and the main engine wire harness connectors and the wiring between the coil/injector and the COP connectors and found nothing.

Pcm connector to coil/injector engine harness connectors wire continuity and resistance results:

pin 26 cyl 1 lg/wht - Continuity 0 / Resistance 00.6

Pin 52 cyl 3 wht/pink - Continuity 0 / Resistance 00.6

Pin 78 cyl 7 pink/lb - Continuity 0 / Resistance 00.6

Pin 104 cyl 2 pink/wht - Continuity 0 / Resistance 00.6

Coil/injector harness connectors to COP connectors wire Continuity and resistance results:

Pin 26 cyl 1 lg/wht - Continuity 0 / Resistance 00.9

Pin 52 cyl 3 wht/pink - Continuity 0 / Resistance 00.7

Pin 78 cyl 7 pink/lb - Continuity 00.1 / Resistance 1

Pin 104 cyl 2 pink/wht - Continuity 0 / Resistance 00.5


i checked the red/green power wire for the coils and traced it all the way back to the fuse box and one of the 3 block connectors right behind the fuse box at the firewall and still found no damage.

Coils 1, 2, 3, 7 are all receiving the 12v while the ignition is on and they are all receiving the 14v while the truck is running.


I did a Resistance test on the injectors and all of them are getting right around 15ohms.

I also did a noid light test on the injectors

Noid light results:

#1- faint flashing every few seconds

#2- faint flashing every few seconds

#3- not as bright slight rapid flashing

#4- bright rapid flashing

#5- bright rapid flashing

#6- bright rapid flashing

#7- not as bright slight rapid flashing

#8- bright rapid flashing


I did a balance test where you disconnect the coils and the injectors while the truck is running and when i pulled coils/injectors 1 2 3 7 nothing happens. The idle stays the same.


I checked grounds and even cleaned where the grounds make contact.


i checked for continuity and resistance on the pins for the pcm and all 8 of the pins for the coils read 0 Continuity and 00.4 Resistance.


A few months ago i sent in my pcm to get repaired hoping they could tell me if it was bad or not. They told me my pcm was fine and that they couldn't find any problems associated to the codes i was getting, but then the dude tried to sell me a remanufactured one. That didn't sit well with me because it seemed sketchy to try to sell me a new one if mine is okay. My thinking is that they tried to play me as an idiot and try to sell me a pcm even though I didn't need one or they didn't even bother to test my pcm bc they are lazy and wanted to get me to just buy a new so they can make a quick easy buck off of me. Idk maybe I'm crazy


I also found a good sized hole in the passenger side plastic wheel well cover and if you look through the hole you can see the pcm and its connector. Idk how long that hole has been there. I haven't been down there to do a brake change or anything for like 2 years so I'm assuming it happened within that 2 year period. So a bunch of water, mud, dirt and whatever else has made contact with the pcm connector. Could that be what's causing this whole problem?


I cleaned the pcm connector, coil/injector engine harness connectors, and those 3 block connectors behind the fuse box with electronics cleaner and a soft brush. I blew air into them with my compressor as well.


I've also read that replacing the crank position sensor and cam position sensor can solve my problem??? I don't know how though. I was at a junkyard not too long ago and got them why i was there for cheap. I haven't put them in yet.

Off the top of my head the only things left to do is to recheck the fuel injector wiring, replace the COP connectors, or my pcm is in fact bad. And i guess I'll replace the crank position and cam position sensors and maybe by some miracle that'll work for me somehow like it did for 3 other ppl i found online but i highly doubt it lol. I'll try anything at this point.

Im kinda lost at the moment so any help would be greatly appreciated. I'm not mechanically inclined so this is all a bit over my head.

 

Put two bottles of Techron or Gumout with PEA in the gas and run it through to see if that helps if you haven't done that already. Could be plugged injectors. How many miles on this engine? Have you checked the fuel pressure?

 

I haven't tried to use Techron or Gumout to clean out the injectors but i think i got fuel injector cleaner in the garage so I'll try it out. The truck has 250k on it and i haven't checked fuel pressure. I want to swap an injector from a working cylinder to a bad cylinder and see what happens.

 

Technically the 'CODES' you list are not _MISFIRE_ codes. That blazing fast and smart computer on your firewall does one hell of a lot more than we casually imagine.

It actually monitors (and detects) the small acceleration bump in crankshaft rotational speed immediately after it commands a spark to a COP. If it doesn't see that expected speed acceleration - it reports a P030x ('x' representing the cylinder).

On the other hand P035x indicates the PCM has determined that it is "ELECTRICALLY" unable to cause a 'spark' across the plug tip. ie: Open Circuit in the Primary of the coil or wiring between PCM and COP, - or an open circuit in the Secondary of the coil. The PCM must see positive voltage (~ +12V) on the COP control wire. When it pulls the control wire to ground, it must draw current (~ 4 to 6 Amps) if the primary coil and wiring is in tact and not high resistance (by poor/corroded connection). When the PCM releases the control wire, the collapsing magnetic field in the coil induces high voltage in the secondary windings. If the the PLUG sparks - current is consumed in the secondary windings collapsing the magnetic field and causes a very large voltage spike, much greater than 12 volts in the primary. (You can see this clearly on an oscilliscope). If the PCM fails to see the 'reverse emf spike' - it knows the secondary of the COP did NOT successfully create a spark and therefore could not possibly produce combustion.

Diagnostically - this is a VERY different condition than a P030x.

If you are getting P0351, 0352, 0353 and 0357 (that is odd), but focus on electrical connections and plug gap(s). You can pull a COP and insert a spare Spark Plug, Ground the spark plug base to engine or frame metal and OBSERVE whether it is sparking or not. If it is and you still get P035x - it would be a problem with the PCM.

 

Thank you for the reply. You did a better job explaining the P035X codes than any website, YouTube video or other forum I've visited. I've only been able to find one person who got the p0351, 352, 353 and 357 codes all at the same time and that was on 02 f150 4.6l i believe. The guy was able to just simply pull out the pcm and reconnect it and be left only with the 353 code.The last thing he said was that he was going to throw a new pcm in it after being unsuccessful fixing the 353 code.

When i replaced the coils i replaced all of the spark plugs as well and made sure they were gapped at 0.054in so they should be good. I'll check my electrical connections/clean them again because it won't hurt to and maybe i missed something there. I'll check the cop/plug to see if I can visually confirm that i am in fact getting spark or not on 1, 2, 3 and 7

 

You should be able to find something like this at the parts store.

 

That's what I was thinking about getting

I was putting everything back together after testing all the wires and connectors so i can see if 1 2 3 7 had spark and now i can't get the truck to start to save my life.

this truck has been kicking my ***

 

Well i still haven't gotten the truck back running again today. The truck will crank and try to turn over but it just won't start. I Tried jumping it off and still nothing. The battery discharges quickly, it dies after 3 or 4 times trying to start the truck until i charge it up again. A few days ago i was checking all of my wires with a multimeter for continuity/resistance and maybe I screwed up the wires. I used a wire piercing probe so maybe i screwed something up and that's why it won't start.

I'm about ready to sell the truck as is for whatever I can get for it at this point.

I'll mess with it some more tomorrow.
Recheck/test wires and COP connectors

 

Go to a parts store and borrow/rent the following:

Fuel pressure gauge
Inline spark tester
A set of noid lights

Check for fuel pressure, minimum 28 psi to start, use the spark tester to check for spark while cranking, use the noid lights to verify fuel injectors are pulsing.

 

I actually have a noid light set i used to test the injectors before i had the no start and all of them were getting pulse from the pcm. Some were dimmer than others and pulsed slower than others.

I heard my fuel pump kicking on while listening at the gas cap

Before I checked all of the wires for continuity and resistance the truck would start and idle roughly

I'll grab the spark tester and the fuel pressure gauge while I'm out in the morning

 

It's been a minute since I last posted about the expedition so i figured I'd update the thread.

I was able to get the truck to start again, it was the battery that was bad. It showed it had 12.5V but it wouldn't start. When i hooked up my battery out of my Ram it started.

The pcm ended up being my problem. I used a spark plug tester to confirm if i was getting spark or not and 1,2,3,7 were all getting spark. It cost me $325 for the pcm and to bring out a locksmith bc of the pain in the *** anti theft system.

Thanks to everyone who posted on the thread and helped me out.

 

Glad you found your issue.
I just wanted to point out for future readers that on MY 97-2002 Coils 1 2 3 7 are on PCM connector C120,
and Coils 4 5 6 8 are on PCM Connector C119. That fits your observed failure pattern exactly.

So, one thing to check (too late for you, and just a check anyway) is to reseat the connectors at the PCM. e.g Disconnect them, and then reconnect them.

As replacing the PCM fixed the issue, the problem was likely a blown capacitor inside the PCM that was shared by all the Coils on C120 (1 2 3 7) . The coils on C119 have their own separate capacitor inside of the PCM for coils (4 5 6 8). Ford does not distribute the PCM design details. But the after market PCM sellers generally take good condition junker PCM's, replace all the capacitors, and then test the PCM unit before sale. (And then they program the VIN and mileage for you). Everything else, you usually have to handle (PATS anti-theft keys), Tire size and differential gear ratio, etc.

But just for others, before buying a new PCM, and going through the reprogramming hassles, is to try and reseat the PCM connectors first with your existing PCM. Every once and while, the connector has just gotten corroded and a reseat (disconnect, reconnect) sometimes solves the problem. Otherwise (most of the time) you end up having to replace the PCM, because a capacitor failed. And on the 1997-2002, the PCM also drives the transmission (e.g. on those MY, the PCM is also the TCM), so when some of the caps go, the Trans stops shifting reliably, or blinks the over-drive light, or both. On the PCM's basically 80% of the failures are bad capacitors, 15% are failed power transistors, and the last 5% is random. (Almost always the capacitors dry out, gas out, and split the cap casing. Most Auto parts (OEM originals ones) use high quality Japanese capacitors (that last about 20 years). Hopefully, the replacements do as well, but Chinese caps are much cheaper, and some places go for the cost savings. (The Chinese caps last 5-10 years, just not as good.) There really are no USA capacitor makers anymore (those were also high quality, back in the day.)