Random Misfires - 2023 2.7 L

[B22-2023]

I have been watching this thread closely and glad there was finally a resolution for @gbub . Of course today I get the attached codes with flashing CEL and rough running/misses pulling out of my driveway. It cleared up after a few minutes, and figured I‘d share here before going to the dealer.

Battery SOC low at 50% so I fully actually expect the various ACM and lost comms errors by now. But a real series of misfires from low SOC? That’s not a thing is it?

Nothing on FordPass except a PCM Malfunction on 5/13 that I can’t open up for details. I’ve read here some guys can look deeper remotely at these things via the VIN.

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[Ducati1098]

Battery SOC isn’t going to cause a misfire.
Without seeing freeze frame data or actual testing it’s going to be difficult to diagnose. It’s also obviously going to be more difficult to diagnose if you can’t recreate the misfire.

If you want to try and diagnose it on your own, personally I’d start with the obvious and easy steps first.

-Do a visual inspection, make sure there’s nothing obviously wrong with the coil wiring.
-If that looks okay, pull the spark plugs on the affected cylinders and see how they look. Make sure there isn’t any carbon tracking on them.
-If the plugs look okay, try moving either the affected coils or the plugs to a different cylinder.
-If the misfire returns and moves to the new cylinder, it obviously means there’s a problem with whichever coil or plug you moved.
-If the misfire still stays in the same cylinder, then you’ll at least rule out the coils and plugs and you’d need to move onto either a potential injector issue or base engine concern like compression or something else.

How many miles are on your Bronco?

 

[Ducati1098]

Also, the loss of communication and ACM codes likely aren’t because of battery SOC either.

The loss of communication codes you have are for the lower active grille shutters. Not sure if you have those disconnected from modifications you have, but I’d guess that’s the likely cause and nothing to be concerned about.

The specific ACM codes may be from any audio modifications you have done. I’ve seen those on other broncos with aftermarket speakers/audio set ups.

 

[Brian_B]

Low SOC can cause random false errors to show up, but I've never heard of Misfire being one of them.

We have one unit at work that will do it though - it's a CAT and not a Ford, but if the batteries start to get weak, either the fuel metering valve will start to misbehave and the unit will start to knock badly (runs excessively lean because the metering valve won't/can't keep up), or it will start to pop false Low Oil Pressure warnings, because the oil pressure sensor starts to drop out of the network.

So... I've never heard of it on a Ford, and it certainly isn't likely - but ... it's remotely possible, either as a side effect or errant/false reading.

With the mods you are running, absolutely do what Ducati is recommending. How the spark plugs look could be pretty telling. I'd also try knocking your JB4 down to something very tame if you haven't already

 

[B22-2023]

Thanks.

Shutters and motor removed, so I am used to that one. The audio and parking ones were new, while my extensive audio upgrades are 2 years old. 14.5K miles on the Bronco.

My plan is to pull the related Ruthenium plugs (1K miles) and look; inspect the connections along the way - maybe something got loose when changing out oil catch can systems the other week. But I will be swapping coils between 2 & 3 for the heck of it.

I have all the freeze frame data, it’s easy to read but hard to screenshot and post; JB4 is off (I only use it on loaded road trips at this point - the plugs, intake, IC and charge pipe mods are plenty of pep for around town).

 

[B22-2023]

Pulled plugs 1, 2 and 3 (pass side) pics in order below, two shots of each plug. Wet with fuel (from a 20 second start/stop to move truck in garage) but fine. Found a socket boot

on No 2 plug at the base, not helpful but probably not a big deal. Reinstalled all, with good connection on all the coil packs, and battery disconnected 20 minutes. Hearing a whistle more recently I also noticed a driver side turbo outlet hose clamp slipped a bit off, though I still have had good boost. Tomorrow I’ll batten that down then drive it and watch for errors or misfires. I wonder if boost was leaking causing an imbalance or something causing the computer to mess up between expected and actual boost. Anyway after the pipe fix and a few more miles on it we’ll see.

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