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06 odyssey 3.5 All cylinders misfiring, bank 1 rich

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  #1  
Old 08-17-2023, 02:18 AM
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Default 06 odyssey 3.5 All cylinders misfiring, bank 1 rich

P0172 and P300

Thank you for any feedback In advance

i’m stumped

the vehicle is idling real rough with CEL flashing every now and then.

B1 short term fuel trims is anywhere from -10 to -27 at any given time. (It will go -5 to -7 at high rpm)

all other trims are within spec range

scanner is telling me 1-6 are misfiring with the random mis code. Bank 1 too rich is pending

both downstream 02 sensors are virtually stagnant and the upstream seem Ok. I changed a downstream sensor and it’s still stagnant

now, I can understand the system is perceiving a rich condition which is why it’s trimming fuel In bank 1. I can’t understand why this would be causing 1-6 to misfire, instead of just 1,3 and 6.

at first I thought vacuum leak but I figured that would affect both banks. I think I ruled out fuel delivery (maybe other then the fuel pressure regulator)

the thing throwing me is that all cylinders are missing

ill add that B2S1 is not going positive at all but it is oscillating up and down I’m the graph.

Please excuse my ignorance I’m fairly new to reading live data and I’m watching every long form video I can to try and become better at reading the data







 

Last edited by Ok_Brain; 08-17-2023 at 02:27 AM.
  #2  
Old 08-17-2023, 06:42 AM
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Originally Posted by Ok_Brain
.I changed a downstream sensor and it’s still stagnant
They are not supposed to switch like the fronts.
I can’t understand why this would be causing 1-6 to misfire, instead of just 1,3 and 6.
Need to look at misfire data.
at first I thought vacuum leak but I figured that would affect both banks.
Intake gasket can do a single back or cylinder.That may be your problem.
I think I ruled out fuel delivery (maybe other then the fuel pressure regulator)
How would that effect just one bank?
I suggest you either read some books or if you need it fixed soon take it to someone who understands automotive.
You are destroying the cat by running this thing with misfires.
 
  #3  
Old 08-17-2023, 08:08 AM
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The check engine light flashes whenever there is a danger of the engine running to destroy itself. In this case running rich can hurt the catalytic converter.
The engine starts in open loop. Meaning engine is cold. The ecu follows a fuel map to get the engine running then keep it running.
Once the engine is warmed up, the system goes into closed loop.
The ECU then uses the data from the upstream O2 sensor (air fuel ratio sensor).
If the spark plugs are not firing well enough to burn all the fuel then ECU can see a rich condition
If fuel injectors are sticky in open position then ECU can see a rich condition
If upstream O2 sensor is faulty then it is possible that the ECU see a rich condition
Downstream O2 sensor is used to measure the efficiency of the catalytic converter
Checking the spark. Blue spark and jumps good distance. Not orange.
Most people would begin by changing spark plugs (make sure the gap is correct)
Some people would even change the upstream O2 sensors.
But, that is just throwing parts at it. One must troubleshoot and find out the cause.
Good luck.

Note: Clogged air filter is possible, bad oil, etc
 

Last edited by avisitor; 08-17-2023 at 08:12 AM.
  #4  
Old 08-17-2023, 09:13 AM
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Originally Posted by grcauto
They are not supposed to switch like the fronts.

Need to look at misfire data.

Intake gasket can do a single back or cylinder.That may be your problem.
How would that effect just one bank?
I suggest you either read some books or if you need it fixed soon take it to someone who understands automotive.
You are destroying the cat by running this thing with misfires.
thanks for your input
 
  #5  
Old 08-17-2023, 09:17 AM
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Originally Posted by avisitor
The check engine light flashes whenever there is a danger of the engine running to destroy itself. In this case running rich can hurt the catalytic converter.
The engine starts in open loop. Meaning engine is cold. The ecu follows a fuel map to get the engine running then keep it running.
Once the engine is warmed up, the system goes into closed loop.
The ECU then uses the data from the upstream O2 sensor (air fuel ratio sensor).
If the spark plugs are not firing well enough to burn all the fuel then ECU can see a rich condition
If fuel injectors are sticky in open position then ECU can see a rich condition
If upstream O2 sensor is faulty then it is possible that the ECU see a rich condition
Downstream O2 sensor is used to measure the efficiency of the catalytic converter
Checking the spark. Blue spark and jumps good distance. Not orange.
Most people would begin by changing spark plugs (make sure the gap is correct)
Some people would even change the upstream O2 sensors.
But, that is just throwing parts at it. One must troubleshoot and find out the cause.
Good luck.

Note: Clogged air filter is possible, bad oil, etc
I really appreciate your reply and thank you for actually giving me feedback on my data. I work for a dealership so I’ll take it into work today and run it on the big scanner and look at the misfire counts. Sorry if my message seemed a bit scattered I work full time and freelance full time so when I wrote this last night I had been working for 12-+
hours. I’ve never hurt anyone’s car and I’ve fixed upwards of 40-60 cars. Only few being live data diags, so this is why I’m a noob when it comes to reading this stuff. Thanks for not being condescending, I’ll check those and report back to hopefully help someone In the future


I’ll add that spark plugs was my knee jerk reaction, just threw me that all would go bad at once? I’ll need to look at the misfire count like someone already said and see what cylinders are having the most problems.

but it’s a new day I’m refreshed and ready to fix t this thing!
 

Last edited by Ok_Brain; 08-17-2023 at 09:22 AM.
  #6  
Old 08-17-2023, 11:46 AM
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Originally Posted by avisitor
The check engine light flashes whenever there is a danger of the engine running to destroy itself.
Note: Clogged air filter is possible, bad oil, etc
FYI it flashes when there is a problem that can destroy the cat not the engine.
How would an air filter affect only one bank?
 

Last edited by grcauto; 08-17-2023 at 11:49 AM.
  #7  
Old 08-17-2023, 12:36 PM
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UPDATE: I checked the misfiring patterns and every cylinder is misfiring almost 200 times in sequence

changed cylinder two spark plug just to test and still missing.

im wondering if the throttle position sensor is stuck a little; however no issues at all as long as you’re pressing the gas

in the scanner all fuel trims go normal and the misfires stop entirely when you give it gas
 
  #8  
Old 08-17-2023, 01:43 PM
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just got done trying to run a fuel injector test on the vehicle and it thought I had my foot on the pedal and that the throttle position sensor was faulty so it could not run the test so that makes me think that’s a throttle body needs to be replaced because you can’t just buy the sensor from what I understand
 
  #9  
Old 08-17-2023, 09:06 PM
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Look at the freeze frame and see when it flags. At idle only?
 
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