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2001 330xi 208k
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Discussion Starter · #1 ·
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I'm on my quest to track down a occasional idle issue. Yes, codes are being thrown around like candy at a parade.

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I swapped out the valve cover gasket just in case it was hard and leaking. I'm changing out the spark plugs next. I'm waiting for a new o-ring for the DISA. CCV was replaced by PO. Fuel pump too.

I have OBDLink iOS app and OMBLink MX+. I know it will only give me some basics. But using the dashboard on the app I can see some of the realtime readings.

I noticed that cold the O2 1 was really low voltage. As it warmed up the voltage went up a little. But always fluctuating.

1. Should I expect O2 1 and 2 to be the same?
2. Is there a target voltage?

I'm still going to check for more vacuum leaks.

 

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having just looked at this, the default for OBD fusion is to look at bank 1 sensor 1 (precat) and bank 1 sensor 2 (postcat)

You need to change the PIDs to look at the 2 precat sensors to get a picture of what's really happening.

On my 5-01 the refresh rate's so slow that it's kind of misleading if you don't know what you're looking for-
the refresh rate is below the cycle rate of the DME, so it gives random results.

t
 

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2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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the refresh rate's so slow that it's kind of misleading if you don't know what you're looking for-
the refresh rate is below the cycle rate of the DME, so it gives random results
Hence the request for the 3 standard logs. They provide the full data set in a form that we know. Otherwise, we're into the "death by a 1,000 questions" game.

@swooshdave
  • The pre-cat voltages should be cycling between 0.1V to 0.8V under normal driving conditions. It will go to 0.9V under acceleration.
  • The post cat voltages should be above 0.5V with a hot engine under steady driving conditions. If they are below 0.5V then you likely have problems.
 

· Registered
2001 330xi 208k
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Discussion Starter · #6 ·
Hence the request for the 3 standard logs. They provide the full data set in a form that we know. Otherwise, we're into the "death by a 1,000 questions" game.

@swooshdave
  • The pre-cat voltages should be cycling between 0.1V to 0.8V under normal driving conditions. It will go to 0.9V under acceleration.
  • The post cat voltages should be above 0.5V with a hot engine under steady driving conditions. If they are below 0.5V then you likely have problems.
This isn't your problem but I'm letting you know so you don't think I'm ignoring you. I'm having some issue with the Apple App Store and can't purchase things. As soon as I get that sorted out I'll get the logs.
 

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2001 330xi 208k
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Discussion Starter · #7 ·
Ok, getting closer.

First I set up a custom dashboard. This is with car idling.
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Then I set up what I thought was the graphing and logging.

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I hit play and ran it for a while. Then hit stop.

When I went to look at the CSV file it just had time, lat, long and speed.

I must have missed a setting somewhere.
<edit> I see what I missed. From a UX standpoint you would assume that you would log what you set up on the graph. Silly me it was in a totally different settings area.
 

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2001 330xi 208k
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Discussion Starter · #8 ·
Ok, at this point I'm going in the right direction but not in the prescribed path. I have some more parts showing up this week and once I get all of those on I will come back to the logging. But at least know you kind folks have pointed me to what I need to do. Thank you. Especially @NZ00Z3
 

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Discussion Starter · #9 ·
In an effort to eliminate typical service variables I replaced the spark plugs and air filter.

I also put an o-ring on the DISA. My theory is that the air box opening gets bigger as the intake ages (heat cycles) and the co-molded gasket is no longer effective.

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I hope to do the tests and get the logs tomorrow although from just monitoring I am assuming there’s a problem.

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My guess is that 27.3% is the max range and the trim is actually higher. I’m also wondering if Bank 1 is negative to compensate for the additional fuel in Bank 2.

The full logs should reveal more.

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Putting on my CSI hat I can see that Bank 1 (forward) O2 sensor looks newer than the back one. Not sure what that means yet.
 

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2001 330xi 208k
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Discussion Starter · #10 ·
Cold_Idle
Highway_Cruise
Hot_Idle

Let me know if you can view the files and have the right permissions. Thanks!

@NZ00Z3

Notes: The cruise was as flat and steady as I can get near me. It's Oregon not Nebraska. There is some up and down.

The Hot Idle was pretty smooth. Other times the idle can be rough. Intermittent issues, my fav.
 

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2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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Just tried to download the files. I have an apple account. Couldn't get them.

A free DropBox account or Google drive have both worked well in the past.
 

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Thank you for the excellent logs. Perfect first time up. Well done.

Here is my analysis file: 20221120 Idle Problems- Swooshdave.xlsx

The Pre-Cat O2 sensor on bank 2 is dead. Recommend that you replace both pre-cat O2 sensors. Then see what is happening.

Time Invested
It took just over an hour to spread sheet your logs and write up this post.
 

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2001 330xi 208k
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Discussion Starter · #17 ·
Thank you for the excellent logs. Perfect first time up. Well done.

Here is my analysis file: 20221120 Idle Problems- Swooshdave.xlsx

The Pre-Cat O2 sensor on bank 2 is dead. Recommend that you replace both pre-cat O2 sensors. Then see what is happening.

Time Invested
It took just over an hour to spread sheet your logs and write up this post.
2001 330xi

I’m afraid to find out how much you charge by the hour. 😁

As I mentioned above the Bank 1 O2 sensor looks newer than the other one. From your analysis it looks like Bank 1 is working. Is your recommendation to replace both based on the data or is it assuming that the sensors are of the same vintage?
 

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Yes, based on the assumption that they are the same age. If bank 1 has been replaced, then only do bank 2.

I work for free, It's my giving back to the forum that has taught me so much.
 

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Discussion Starter · #19 · (Edited)
Yes, based on the assumption that they are the same age. If bank 1 has been replaced, then only do bank 2.

I work for free, It's my giving back to the forum that has taught me so much.
I obviously greatly appreciate your input.

Now off to shop for the 02 sensor. Then I'll post my logs again. It'll be a good comparison.

<update> Placed order with Pelican. Hopefully with them being in CA they will get here shortly.
 

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Discussion Starter · #20 ·
Replaced sensor. Will pull new logs. I had warmed the car up to get sensor out so couldn’t get clean logs. But initial readings look a lot better.
 
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