Misfire on driver side cylinders

[neema]

Hey all, I'm having an issue


Recently I blew the internals out of my driver side magnaflow cat (from their catted X) and took out the downstream o2 sensor on the driver side.

The car threw a p0161 (fault with driver side downstream o2 sensor) and eventually a p0302 (misfire on cylinder 2)--presumably because the car was running rich with a cat missing.

I fixed the cat and o2 sensor but the car still stumbles and misfires pretty bad. The car throws a p0302, p0308, and p0300 (misfires). I checked spark plugs and each plug on the driver side was covered in black soot (nice and rich). I changed them all and I'm still getting bad misfiring.

Any ideas?

 

[Kenaizer]

Have you data logged the issue? That might give you a better idea of what's going on

 

[G.T]

i'd do a compression test and check your engine oil for any signs of metal/debris as a catalytic converter failure could be a bit more catastrophic than just a failed exhaust system component!

catalyst dust/flakes could get sucked back into the engine and collect on the sides of the piston scuffing the cylinder walls, or get pushed past the piston rings, mix in with the oil damaging bearing surfaces

 

[DGRacing]

I don't have cats on my race car and its not catastrophic.
Any normally working motor WON'T have any vaccum pressure in the exhaust manifolds while the exhaust valves are open. It wouldn't run.

 

[Scuba-Matt]

Did you check the #2 injector to make sure its working properly? I had a similar issue on my 5.4 expy. The injector was stuck open fouling the plug, f-ing up the cat and sending the codes.

 

[neema]

Did you check the #2 injector to make sure its working properly? I had a similar issue on my 5.4 expy. The injector was stuck open fouling the plug, f-ing up the cat and sending the codes.

That's next. I'll dive into it over the next couple days and report back. Fingers crossed for no internal engine damage.

 

[86GT351]

You also stated P0308 which is the Drivers side.

 

[G.T]

I don't have cats on my race car and its not catastrophic.
Any normally working motor WON'T have any vaccum pressure in the exhaust manifolds while the exhaust valves are open. It wouldn't run.

that would be true IF the valves closed EXACTLY at TDC.. as the instant the piston starts moving down, it will create negative pressure, regardless how little and how long it lasts.

p.s: i've only come across this particular issue and the photos on a Ford technical white paper "Engine Failure Analysis & Tips - Ford Motor Company - June 2013"

 

[Eel Mit]

P302 is cyl #2 passenger side,
P308 is #8 driver's side,

so you have issues on both banks.

Pull the plugs and look at them , compression test and leakdown if necessary.

 

[neema]

Got an update: two coilpacks have gone bad. Getting them replaced tomorrow. We'll see if that fixes the problem

I want to know what the cause of them failing was. The tiger racing hood? The car is always garaged.

 

[neema]

Well, today I picked up the car with the misfire still occurring. It's been at the dealer for quite some time and they weren't able to elevate it to a ford engineer because of the headers I have on it (the only modification done to the motor).

I ordered some front o2 sensors in case one of the stock ones were fouled. Lo and behold, the driver side sensor was black and sooty. I popped in the new ones and the car runs great. Go figure.

Just a subtle reminder that before you assume the worst, try the easy stuff first. Also, another reminder is to make sure that if you have the dealer fix it, at least make sure they check the easy fixes first, too. My tech was sure that the o2 sensors were okay purely because the scan tool didn't indicate they were malfunctioning.



On the other hand, my midpipe just slipped off my headers on the highway, which scared the bejeezers out of me. It sounded like someone opened up some cutouts followed by lots of clanging. I'm sitting here waiting for help to bring me a floor jack and some tool. Joy

 

[ArizonaGT]

At least it was something simple and relatively inexpensive

 

[Grabber Blue 5.0]

I had the same thing happen to me over the Summer. My midpipe blew off my catback when I launched the car. Those factory clamps look like they should have held but they didn't. My catback and midpipe don't fit well with that clamp though and leave a good part not clamped on both ends.

 

[Rob72]

I ordered some front o2 sensors in case one of the stock ones were fouled. Lo and behold, the driver side sensor was black and sooty.

What brand headers? It's a possibility that some brands are prone to this due to the angle that the O2s are screwed into the header.

 

[neema]

The fouled o2 sensor was mounted in the stock header with a magnaflow catted xpipe.

We'll see how ARH headers hold up

 

[Rob72]

Well, today I picked up the car with the misfire still occurring. It's been at the dealer for quite some time and they weren't able to elevate it to a ford engineer because of the headers I have on it (the only modification done to the motor).

The fouled o2 sensor was mounted in the stock header with a magnaflow catted xpipe.

???

 

[neema]

???

Good catch. The misfire started when I had stock headers and the catted magnaflow x-pipe. The cats disintegrated and fell apart from a rich condition so I had to replace them... and I did so with ARH catted long tubes.

So (unknown) fouled o2 sensor->magnaflow cats disintegrate->replace with ARH headers->turned into dealer to inspect the car

 

[Rob72]

Good catch. The misfire started when I had stock headers and the catted magnaflow x-pipe. The cats disintegrated and fell apart from a rich condition so I had to replace them... and I did so with ARH catted long tubes.

So (unknown) fouled o2 sensor->magnaflow cats disintegrate->replace with ARH headers->turned into dealer to inspect the car

Thanks for clearing that up. I know that these widebands don't like moisture.

 

[RocketcarX]

Shouldn't step one in a misfire situation be to swap the offending coil to another cylinder and wait to see if the misfire moves? This whole thing is way over complicated, it's a FORD, it astounds me that the coil wasn't the first suspect.

If the scan tool says all is well with the O2 and the readings look good, it's swinging and basically matches the other bank…it's fine, not really a part you need to pull to know it's defective.

I would go back to square one, make sure you are properly identifying coil # by locations, swap it to a known good cylinder, if the misfire moves, bingo.

On a side note, it sounds like you are still suffering from some kind of rich condition, all the plugs on one bank being covered in soot with no other indicators of a failure, vacuum leak, other engine codes things like that, leads me to believe you need a better tuner as well. I could be way off, but this is just what I can gleam from this thread.