Bank 1 misfire

Bullitt347 · May 1, 2024

Another item of note is that you can get a P0171 with a rich or lean condition.
As mentioned previously, the O2 sensor is sensing Oxygen, not fuel.
So if the engine is so rich that combustion can not take place, (misfire) then lots of Oxygen can be present in the exhaust.
The converse is also true. The engine can be so lean that combustion can not take place (misfire) and lots of Oxygen can be present in the exhaust.

Bullitt347 · May 1, 2024

If you are not getting a P0420, (Bank 1) or a P0430, (Bank 2) then your Catalyst are currently working as they should.

austin21 · May 1, 2024

Bullitt347 said:
If you are not getting a P0420, (Bank 1) or a P0430, (Bank 2) then your Catalyst are currently working as they should.

Thank you, I have done a smoke test and I did not find any vacuum leaks or leaks through the procharger piping or intake manifold.

At this point I’m thinking it has to be something fuel related unless I have a exhaust leak before the o2 sensor or the EGR is stuck open. I have a new EGR valve but I’m having troubles getting the current one off

The fuel filter is a pain in the ass on this car due to the IRS. I can hear the fuel pump prime when I turn the car on. The fuel pressure kit I bought on Amazon did not have the right fittings. So the fuel pressure is still unknown.

Bullitt347 · May 1, 2024

Can you please clarify you initial post where you state "misfire on entire bank 1 (Cyl 1-4)."
A P0300 is a random misfire, no cylinder identified. If a cylinder is identified, then a code of P0301, for cyl #1 will be set.
A P0302 is cylinder #2 and so on for all 8 cylinders.
Are you stating that you had codes P0301, P0302, P0303 and P0304?
Or are you just basing it off of a P0171, Lean Bank 1?

austin21 · May 1, 2024

So my tuner initially stated I had a misfire on bank 1. I never got a code for it or anything just basing that off his words. He was basing that off the sound of the idle, video posted above. Honestly he could have been bullting me because he was super swamped at the time, and I don’t really know him that well. He is the only guy in my area that was reputable.

I took the car back because my tuner didn’t have time to try and chase down the issue.

I took the car home and started trying to chase down this “misfire”. I had gotten p0171 a month or two prior but I cleared the code and it never came back. I went ahead and replaced the spark plugs on both sides. The coils were replaced a few months prior so I tested spark by grounding the plug to the engine block. that checked out

After buying a obd2 scanner I notified the fuel trims were very wacky. My tuner suggested I send the fuel injectors off to get cleaned so I did. They were not a problem and came back good. Since then I’ve been trying to figure out the fuel trim problems.

I never got a CEL code for any misfires. Only p0171 and p0174.

Bullitt347 · May 1, 2024

Lots of things can cause P0171/174
Vacuum leaks
Exhaust leak
MAF sensor
MAP/Baro sensor
Compression/ring seal
Timing
Anything that can disrupt combustion
Is your MAF a blow through or before S/C?

austin21 · May 1, 2024

Bullitt347 said:
Lots of things can cause P0171/174
Vacuum leaks
Exhaust leak
MAF sensor
MAP/Baro sensor
Compression/ring seal
Timing
Anything that can disrupt combustion
Is your MAF a blow through or before S/C?

MAF is a SCT BA2600 90mm. Located after the supercharger in the fender well before the intake. I cleaned that and I’m getting good reading on the OBD2 scanner for the MAF

Checked for vacuums leaks but I did not find any. Timing chain/camshaft drive kit was replaced 2 years ago with new valve springs and comp cams xe-r

It could very well be an exhaust leak, haven’t had time to check out the exhaust yet.

I plan on doing a compression test just to make sure thats squared away.

alwayshi · May 2, 2024

austin21 said:
MAF is a SCT BA2600 90mm. Located after the supercharger in the fender well before the intake. I cleaned that and I’m getting good reading on the OBD2 scanner for the MAF

Checked for vacuums leaks but I did not find any. Timing chain/camshaft drive kit was replaced 2 years ago with new valve springs and comp cams xe-r

It could very well be an exhaust leak, haven’t had time to check out the exhaust yet.

I plan on doing a compression test just to make sure thats squared away.

Damn I missed a lot during work!

I tried to smoke test my exhaust - and found it difficult.
I ended up shoving a vac shop into my exhaust and setting it up to “blow”. I then went under the car and sprayed soapy water near the o2 sensors, where header meets the head etc.
this process was way easier

austin21 · May 3, 2024

Thanks! I dont have a garage so i wasnt trying to do this without a lift.

I got the fuel filter replaced today and the exhaust inspected for leaks, no leaks found. I was able to replace the EGR the other day after letting PB blaster soak overnight.

Going to pick up the car later so i will monitor the fuel trims.

Have to say, i have learned a lot in this process so i appreciate everyone taking the time to explain everything. I am going to get the car re-tuned also at the end of the month by a more reputable shop that will hopefully get me straight. Will keep you all updated.

Mustang5L5 · May 3, 2024

You can still read misfires with an OBD2 scanner. I think it’s PID 106 or 126. I have that number stuck in my mind because I just had a similar issue on my car. It will count misfires, but won’t tell you on what cylinder. Just total. I was getting 5-6 misfires every 2-3mins while idling with fuel trims in the +14-18% range at idle. No codes.

I cleaned my MaF. Now flows about 5.00 gram/s. I also replaced both upstream O2s with new sensors and that seemed to do the trick. They seemed a bit sluggish and would drop to zero longer than I liked.

Both my rear o2s seem to stick right around 0.600 volts.

austin21 · May 4, 2024

Mustang5L5 said:
You can still read misfires with an OBD2 scanner. I think it’s PID 106 or 126. I have that number stuck in my mind because I just had a similar issue on my car. It will count misfires, but won’t tell you on what cylinder. Just total. I was getting 5-6 misfires every 2-3mins while idling with fuel trims in the +14-18% range at idle. No codes.

I cleaned my MaF. Now flows about 5.00 gram/s. I also replaced both upstream O2s with new sensors and that seemed to do the trick. They seemed a bit sluggish and would drop to zero longer than I liked.

Both my rear o2s seem to stick right around 0.600 volts.

I just figured out how to create a config for the SCT x4. Going to use that to datalog and hopefully see misfires.

You can audibly hear the misfire when the car goes into closed loop. The car idles fine until it gets up to temp and the O2 sensors take over. I did replace the upstream sensor on the affected side but wondering if it could have been bad out of the box. I might try to swap another one in and see if there is any change.

Whats odd is that the lean trims are not consistent. I was driving back from the exhaust shop and a few times i came to a red light the fuel trims were fine. Other times they were not, and showing lean +20% give or take.

It has to be either the O2 sensor, or ECU? I have narrowed down everything else. Bank 1 is perfectly fine so i dont think its a fuel restriction from the fuel pump. Also got the fuel filter replaced yesterdy also.

Im wondering if i should just unplug the O2 sensor and ride around like that until i can get it figured out at the end of the month.

austin21 · May 4, 2024

datalog1

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Got a quick datalog this morning from a cold start.

austin21 · May 4, 2024

Alright so been monitoring misfires. Seems like ALL 8 cylinders are misfiring, some more than others......

Under load the misfires don't appear to happen. heres a datalog with fuel trims and engine rpm and well as misfires.

I still cannot determine if the engine vibration is the aftermarket camshafts or not, which the aftermarket cams could be causing a false misfire.

datalog1

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austin21 · May 6, 2024

Replaced all EGT components. Fuel trims seem better.

I believe the misfires are from the cams, cylinder 1 has me a bit worried from previous data log due to large amount of misfire.

Bank 1 misfire

Bullitt347

I have been doing it wrong this whole time

Bullitt347

I have been doing it wrong this whole time

austin21

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Bullitt347

I have been doing it wrong this whole time

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I have been doing it wrong this whole time

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That is…until I whipped out my Bissell

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Bank 1 misfire

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