2014 w/random misfires (Roush supercharged)

[Brad12]

I've taken my truck to the dealer three times now, and they haven't been able to diagnose the issue. I'll do my best to list out the sequence of events in order and where we are today. I could really use your guys' help here because I'll be chasing for the Baja 1000 in a month and I need to resolve this before then. Also, I've searched the forums, googled the problem, and watched a bazillion youtube videos, so I'm really trying here.

December 6, 2020
- On the second day of an offroad trip through Death Valley, my truck throws codes P0303 (misfire detected cylinder 3), P0353, P0356 (ignition coil "F" primary control circuit/open), P0171 (system too lean bank 1) and P0174 (system too lean bank 2) for the first time. Results in rough idle and loss of power
- It gets towed to the dealership where they say it's now only throwing code P0353, so they install an "overlay" which basically means they spliced into the harness and ran new wires from where the harness plugs into the PCM to the ignition coil on cylinder 3.
- The codes go away, the truck is running good, so we think everything is fixed.... but we're wrong.

February 14, 2021
- Again, I'm on another offroad trip coming back to CA from Las Vegas and it throws codes P0353 and P0356.
- The truck throws these codes for about 30 mins while we try to troubleshoot, and then all of a sudden the codes disappear and the truck starts running just fine, so I drive it home.

March 20, 2021
- I'm driving home from dinner on normal city streets and, you guessed it, the truck throws P0353 again.

March 21, 2021
- As I'm going through the troubleshooting process, the truck throws codes P0353 and P0356.
- I install a brand new motorcraft coil on cylinder 3 to no avail, so I take it back to the dealership and it's now throwing P0356 as well. They install another overlay on cylinder 6 and the truck starts running just fine... again.

July 24, 2021
- I don't remember what I was doing, but the truck throws code P0600 (Serial Communication Link)
- If I remember right, this code just disappeared. I don't remember doing anything to fix this.

Fast forward a few months and a couple of offroad trips through Baja and northern CA with no issues.

October 2, 2021
- Again, I'm on an offroad trip about to go up a hill and bam! It throws codes P0111 (Intake air temp. sensor 1 circuit range/performance bank 1), P0355, P0356, P0357, & P0358. So basically the entire driver's side of the engine is throwing an open circuit code to all of the ignition coils.

October 5, 2021
- We swap in a new alternator and battery just to see if that helps, but it doesn't, so we swap in the original battery and alternator. So the truck gets towed to the dealership and guess what? It stops throwing all of those codes as soon as it's taken off the tow truck and it starts running great.

October 15, 2021
- I went to pick up the truck from the dealership and I made it about 100 yards before it started hesitating, idling rough, and losing power. It once again threw codes P0355, P0356, & P0357 (but notice it didn't throw P0358 like it did before) - which it hadn't done the entire time it was with the dealership. So I turned around and took it right back to them and that's where the truck is right now.

Troubleshooting efforts to date:
- Overlays to cylinders 3 & 6
- Checked and cleaned the MAF every time it threw codes
- Visually inspected all hoses, tubes, etc. in the engine bay and everything looked good
- As I mentioned above, I tried a brand new alternator and good battery, but since that didn't fix it I swapped in my original parts (DC Engineering 270amp alternator and Optima Yellow Top)

The dealership thinks it's an electrical issue with either the PCM or the harness. The unfortunate thing about the harness is that it routes between the engine and firewall and they said the supercharger needs to come off in order to access/replace it. They gave me a rough quote of $2,400 to replace the harness. It's also difficult to believe it's the harness because, if you notice the sequence of events, I had two overlays installed and still had the same code for one of those cylinders after the overlay was installed- so I'm not confident it's the harness.

Next steps:
- Replace all of the spark plugs with the correct gap (0.030) and NGK 6510s as recommended by multiple people on the forums and multiple tuners (JDM for example). I had my spark plugs replaced about 30K miles ago (the truck has 126K miles on it). I inspected the spark plug in cylinder 3 and it looked good, but unfortunately it was replaced with a cheap one (Autolite) and it had the original gap (0.044).
- Check all grounds (does anyone have a diagram for these?).
- Check for vacuum leaks.
- Replace the PCM and obviously make sure it gets the Roush flash to make sure it works with the supercharger.
- If that doesn't work, replace the harness with a new one.

I hate throwing parts at problems, but the dealership hasn't been able to accurately diagnose this and I don't know any shops around me that specialize in automotive electronics, so I'm not sure what else to do. I doubt the actual coils are the problem because I replaced one that didn't solve it and the problem is with random cylinders at random times.

If you've made it this far, I really appreciate it and I'm open to any and all ideas on how to fix this. Thank you in advance.

 

[FordTechOne]

You're going to want to focus on the electrical DTCs (P035x) before chasing the conditional DTCs (misfire and lean air/fuel ratio). Note that the electrical DTCs are for the Primary side of the ignition system, a failure on the Secondary side of the ignition system (spark plug or wire) will not cause these DTCs to set, so those can be disregarded.

All of the ignition coils receive power from fuse F78 in the BJB. With Primary ignition DTCs for multiple cylinders, I'd start by verifying that fuse is in good condition and fully seated. It's not likely that multiple ignition coils are all failing at the same time or that the circuits between the PCM and each coil are failing simultaneously either, especially after being overlayed.

These are the possible causes of Primary ignition coil DTCs:

• VPWR circuit open
• VPWR circuit short to ground
• Coil circuit open
• Coil circuit short to voltage
• Coil circuit short to ground
• Damaged Coil

You can rule out VPWR short to ground, as that would open F78. If there are no issues with F78, I'd check connector C1010 next. It's a black 16 pin connector located in the passenger side rear of the engine compartment. Inspect for water intrusion, corrosion, pushed out pins, or physical damage. As the dealer mentioned, the harness runs over the engine, so in your case under the supercharger. If it is pinched between the engine and S/C, the circuits may be damaged within the sheathing, which can cause high resistance.

 

[CoronaRaptor]

If the dealer has to take the supercharger off to repair, I would replace all the coils at the same time with that mileage, I just did my 2nd set of plugs at 148k. Good luck.

 

[Brad12]

@FordTechOne thank you for the info. and suggestions.

Is connector C1010 the one with the blue arrow pointing to it in the pic below? If so, I briefly inspected it and didn’t notice any of the things you mentioned, but it was a quick inspection and I’ll do a more thorough check when I can.

 

[MTF]

Don't waste any money on getting the Roush tune, JDM is the best you're going to get!!!
This is proven hundreds of times on this forum from Roush owners.

And if the PCM were bad, it would not be random.

I read that they overlaid some coils not sure where they taped into, but.
You should to open up the connectors yourself and look inside, not just the pins.
And check all three connectors, Ford didn't do a great job of taping up the ends of the connectors.
Dirt, salt and grime does get in there and can short things out.

I put up some photos up on how to take apart those plugs years ago

Cylinder 8 misfire engine light

Can you borrow a timing light just see if there is really no spark on cylinder 8?

www.fordraptorforum.com

Also, have you checked the connections down by the starter?
This is pretty common that they get loose and corrode between the cable connections.
Not that this is the fix but it is something you should take care of.
And the ground cable from the battery at the frame connection is another place to check carefully.

Have check the wire harness down on the drivers side frame rail just behind the front tire?

Are you running headers?
It doesn't look like it from the photo but it's hard to tell.

 

[FordTechOne]

@FordTechOne thank you for the info. and suggestions.

Is connector C1010 the one with the blue arrow pointing to it in the pic below? If so, I briefly inspected it and didn’t notice any of the things you mentioned, but it was a quick inspection and I’ll do a more thorough check when I can.

View attachment 324815

That’s the PCM connector; C1010 is an inline connector located between the PCM and ignition coils.

 

[Brad12]

@MTF - Ya, I've been seriously considering the JDM tune, so now is probably the right time if I end up replacing the PCM. Although, I'm doubtful at this point that it's actually the PCM. Thank you for the link on how to inspect the connector, I'll be sure to do that as well as all the other items you mentioned. I do not have aftermarket headers.

 

[MTF]

I only mentioned headers because you need to inspect the O2 wires,
if they have been moved or not properly tied up, even when the SC was installed,
they can burn up and send incorrect values to the PCM.

 

[Brad12]

So I finally got an update from the dealership and apparently everything checks out ok based on what you guys have recommended so far.

However, they found some wires that are frayed going to one of the radio suppressor capacitors (aka radio ignition capacitor) and they are recommending I should have both of them replaced for $750. I never even knew these things existed until today and they are literally a $7 part. They are also easily located on the front of the engine, so I'm not stoked about the quote.

Regardless, I only found one thread on here about these capacitors and it looks like they reduce engine noise. It sounds like the idea is that if engine noise isn't being reduced it can cause radio signals to interfere with the PCM.

Does anyone have any idea if this could be causing my issue? Does anyone have any experience with these capacitors causing issues?

 

[Brad12]

The radio suppressor capacitors turned out not to be what's causing the issue, so we're replacing the PCM next.

Does anyone know of a reputable place to get a new PCM or have mine inspected and refurbished? It would be especially helpful if you have a recommendation for a person/shop that's located on the west coast. Thanks.