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jfoj, I used to just replace the sensors no quesitons asked then read an article years ago that changed my mind on just replacing, they are very delicate sensors I agree but they sometimes just get gummed up, I did a bunch of research when I was driving my Fords and VW's and found one cleaner that seemed to work Great: http://www.amazon.com/CRC-05101-QD-...d=1404139538&sr=8-1&keywords=electronic+spray

I have used it on my front two o2's and the codes I had went away, the rears are a pita to get under the car so I haven't done that yet, with the success of the more delicate of the A/F o2's I want ot try them as well, but time will tell. I use this as a temporary fix at best, but I have gotten an additional 30k out of o2's before by simply one cleaning... It's not an end all be all but there is electrical circuitry in them and it works...

With that being said, I will replace all of them, but I am wanting to wait till I do the headers before I do that honestly....
 

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jfoj, I used to just replace the sensors no quesitons asked then read an article years ago that changed my mind on just replacing, they are very delicate sensors I agree but they sometimes just get gummed up, I did a bunch of research when I was driving my Fords and VW's and found one cleaner that seemed to work Great: http://www.amazon.com/CRC-05101-QD-...d=1404139538&sr=8-1&keywords=electronic+spray

I have used it on my front two o2's and the codes I had went away, the rears are a pita to get under the car so I haven't done that yet, with the success of the more delicate of the A/F o2's I want ot try them as well, but time will tell. I use this as a temporary fix at best, but I have gotten an additional 30k out of o2's before by simply one cleaning... It's not an end all be all but there is electrical circuitry in them and it works...

With that being said, I will replace all of them, but I am wanting to wait till I do the headers before I do that honestly....
The cleaner you are using likely had no direct impact on the O2 sensor codes.

Also the O2 sensor codes that do trigger are rarely for a bad O2 sensor, they are usually for a bad heater in an O2 sensor, or the code is due to a fuel mixture issue and not really the O2 sensor.

I find most of the faulty O2 sensors that I flag never trigger any codes!!

Not going to take this thread off course too much, but read this thread and look at the O2 sensor graphs on the 2nd page and you will see how easily it is to pinpoint a questionable O2 sensor with graphing - http://forum.e46fanatics.com/showthread.php?p=16203126
 

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Discussion Starter · #25 ·
Just checked my Fuel filter vacuum hose and it is fine, will replace the fuel pump relay soon as advised.

Back to the issue now, I did swapped the 2 post cat O2 sensor and re-ran the idle test from cold. Today I got code P0305 pending - misfire cylinder 5
Here are the graphs : Link

To perform the test I had to move the post cat O2 sensor front connection out of his bracket due to the sensor cables been attached to the correct length, so if the swapped has been done before, it has been well done. Both plug coming from the sensors from behind the engine are identical.
I double checked the secondary air pump, it is working as expected during the beginning of the startup.

Looking at the way injectors are plugged, I really doubt they can be swapped connection wise.

I'm interested in testing the MAF sensor for VE, will do it as well, thanks for the head's up

As stated before, I'm fighting with the issue for months so I'm not in a hurry of solving it. I understand that it will require patience and method.

I will continue to collect data using torque and I just ordered a USB/K+DCAN adapter so I will then try to get INPA working on a laptop in order to extend my troubleshooting potential.
 

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caribou,

I'm still having some issues with with your warm up and O2 sensors.

I am trying to compare apples to apples here

I know you are primarily concerned about cold start issues, but there may be more to all of this as well.

I went and pulled one of my reference graphs of an E46 that had lazy pre-cat O2 sensors, we just then replaced the pre-cat sensors and graphed the sensors just after replacement.

I then had to make the graphs for the same period, then overlaid the 2 graphs.

What became apparent is 2 things.

1. The pre-cat O2 sensors appear to be slow to respond, although they seem to have the appropriate Voltage swing, either the DME or the O2 sensors are not switching fast enough and I would put my money on the O2 sensors.

2. The SAP is in fact working, however, there is not the deep "V' drop in low Voltage that I would expect. This means one of 2 things. Either the SAP is not working well enough, Kombi valve vacuum line is cracked/broken and/or the O2 sensors are not responsive enough during the warm up cycle.

You can see the graph of the new sensors in this thread - http://forum.e46fanatics.com/showthread.php?t=1041726&highlight=

Please note that there is an anomaly with the pre-cat Voltage in the 15-30 seconds time frame. This car still has some leaking hoses for the SAP. If you draw a line for the pre-cat sensors that mimics the green line (Bank 1, Sensor 1) between 15-30 seconds, this is what good O2 sensors and a properly operating SAP should look like. O2 sensor switching/toggling time should be about 1 time per second, you will see on your graph the pre-cat O2 sensors are only switching every 2-4 seconds. This is hard to see for sure, depends on your polling interval and how many sensors you are polling. Make sure you set up to only graph the O2 sensors and RPM as this will limit the polling cycle between sensors.

Not sure if you have a graph of the O2 sensors once fully warmed up, meaning after driving for 30+ minutes and/or any data from highway cruise.

I would like to see this to analyze this a bit further.

A few other thoughts, this car has a manual transmission, do you know if clutch was ever replaced before you purchased the car?

Also what do you know about the crank sensor?

Sorry if I have to ask again, I deal with a lot of different cars, people and forums so sometimes these cases start to run together. Have you smoke tested the engine and crankcase? I think I asked about this. Also do you know if the power brake booster might have a leak?
 

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Discussion Starter · #28 ·
Thanks for the details and reference about the graphs.
I will try to remove other probes from the polling, may be reducing the polling rate to half a second as well.
I don't have any data with a fully warm engine and highway cruise for the moment, at least none containing O2 sensor polling.

Since the SAP is running and that I just replace the complete line of hoses from the valve to the manifold, I think I will have to double check if the SAP valve is opening/closing correctly to understand what is going on here.

About the clutch, I did ask for it to be replaced 6 months ago because it was starting to worn out.

No idea about the crank sensor.

Regarding the smoke test, yes we already discuss that earlier, I plan to do it in the upcoming weeks. I suspect a leak somewhere around cylinder 4-5-6, may be an injector O-ring, may be the manifold gasket or one of the 2 connections underneath the manifold (brake booster & tank valve).

The engine does a loud air sucking noise when throttling hard from idle and then the RPM raise after a little delay, some say it is normal, some say it's not. Is it similar with your cars guys ?
 

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OP I have been having the same issue with my car since I bought it, and it gets worse the colder it is outside. Once the car is at operating temp it runs fine with no issues and my gas mileage is right where it is supposed to be. I have checked DISA and intake boots as well as swapped coils between cylinders with the same issue. I am throwing the p0300, p0301, p0302 etc... codes. Basically misfires codes across all cylinders. I came across this video on this forum and I wanted to get some discussion going about. I am sure that some of you may have already seen it but the theory this guy has makes sense. what are your opinions?

https://www.youtube.com/watch?v=_Vo4fm0JDPY
 

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Leave the Torque polling at 1 second as this way things will be consistent.

With your longer graph the SAP "V" was not as obvious until I went and shorted the data length to 3 minutes, then compared it to the graph from the other thread. You have a "V" but it is shallow and not deep enough. Tells me the O2 sensors are not responsive enough.

If your SAP vacuum hoses are new and as long as the main hose is not leaking, then this is leaning me more toward the pre-cat O2 sensors lazy/slow to respond.

Assume no change since the clutch work was performed?

Smoke test when the engine is stone cold, even a slight bit of heat can seal things up.

As for the sucking noise, most of these engines sound like they have a vacuum leak at idle, this is the idle bypass noise from my understanding. Hard to qualify what is "normal" without physically being there, but I would not get too worried about it.

As for O2 sensor, I usually go with Bosch. You may be able to get them on Amazon for a decent price, but you have the VAT that is not fun!

Make sure you get the proper O2 sensors, many times application guides mix up the front and rear sensors. The connector genders are opposite and they will not plug in of the wrong sensors are sent.
 

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Discussion Starter · #31 ·
Correct, no change since clutch replacement but I'm curious about how this could be linked ?

So you do think I should consider replacing both pre-cat sensors ? There are about 70€ each around here. Not cheap but at least my car doesn't have the wideband ones that are almost twice as much.

What about the post-cat ones for now ? (These seems to be a pity to replace)
 

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Discussion Starter · #32 ·
Did replace the fuel pump relay today, obviously no change on the issue but always good preventive maintenance.

I check the Volumetric efficiency as discussed earlier, it looks normal as I ended with a VE of 85%. My MAF is off by 3% according to the spreadsheet.

I now have a K-CAN OBD adapter with INPA working so I can now provide new data and time frames.I Took the opportunity to reset the adaptation values so that we can have a fresh start.
 

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Keep us updated on your progress, this is an issue that affect a lot of 330's.

Sent from BimmerApp mobile app
 

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Jfoj has been kind enough to help me with some O2 sensor data recently and has asked that I post the following graphs.

To borrow some of his language, the attached graphs help illustrate the difference that fresh sensors can make and how much quicker they warm up and function. The third graph (pictured below) is a direct comparison of the before and after performance/signature:



1st Attachment: Old Pre-cat O2 Sensors - Cold Start
2nd Attachment: New Pre-cat O2 Sensors - Cold Start
3rd Attachment (above): New vs Old Pre-cat O2 Sensors - Cold Start

Also, for anyone who’s interested, Amazon currently has the Bosch 13477 sensors (#11781742050) for 15% off. Ended up paying $41.49 each: http://www.amazon.com/gp/product/B0...de=as2&tag=toolrec-20&linkId=U5RW4L7A63GPVKRY
 

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Jfoj has been kind enough to help me with some O2 sensor data recently and has asked that I post the following graphs.
Thanks to SilverVogel for posting the graphs, I have run out of attachment space on the forum as I have a number of picture heavy threads.

So for anyone trying to figure out what is going on and what we are doing here what we are going.

After a long time dealing with driveability issues and a lot of work with other members here and on other forums I finally detemined that the best way to check and verify a "standard", non wideband O2 sensor is to graph the sensors on warm up. What we have found is there are MANY, MANY lazy and slow to respond O2 sensors that will never trigger any DTC/trouble codes. What happens is these lazy/slow to respond sensors cause fuel trims to climb, poor fuel economy and at times even other performance and driveability issues. This is partly due to the how the Adaptions adjust and shift once the O2 sensor(s) degrade.

Interesting enough O2 sensors are consumable, they need to be replaced like spark plugs. But that being said many times they can last more than 10 year/100k miles. After a lot of thought and data gathering, what has become clear is O2 sensors rarely trigger DTC's or trouble codes unless the heater circuits fail. So we have resorted to cold start graphing of the O2 sensors and we have been able to consistently and reliably identify degraded sensors and condemn them as needed. In many of these cases the sensors may not be the ultimate source of the original complaint, however, in the process of "Whack A Mole" most owners have decided to change out the O2 sensors that we have flagged as questionable/lazy/slow responders.

Due to the fact we can gather data and graph the sensor performance, owners are more likely to replace the sensors if they are in question rather than "blindly" replacing the sensors and having no idea if they were bad to begin with and there was not solid proof the replacements were any better. Now we have proof of before and after O2 sensor performance.

One thing we have also been seeing is Emission Readiness Monitors not clearing and many of these cases have been directly caused by lazy/slow to respond sensors that also had lower overall Voltage swings. All the Emission Readiness Monitors rely on the O2 sensors for almost all aspects of the Monitors changing to the Ready or Pass state.

If you look at the graph of the new sensors, you will see a deep "V" that starts almost immediately when the engine is started and then sharply cuts off around the 66 second mark. This is the SAP pump running and adding additional air into the exhaust stream, then the sharp transition is when the SAP actually turns off. So I can detect how well the SAP is running and for how long with these graphs.

You can see how the old sensors are very sloppy and slow to respond, they have a very shallow or non existent deep "V" and slow overall switching time.

A fresh and active O2 sensor should have switching transitions about once a second. In this graph the new sensors do switch rather quickly and often, then the switching time does decrease a bit as the graph progresses.

I suspect we still have some issues with this specific car, but the Adaptions were not cleared and we will need to wait a few weeks for the Adaptions to adjust and will revisit the O2 sensor switching time then and see if there are other issues with this specific car.

This is a great way to test for O2 sensor performance. The problem is very few OBDII tools allow this type of data gathering. You will likely need a smart phone App or a computer based program to record or log the OBDII PID's and then graph the data. Most hand held OBDII scan tools to not have the ability to record the OBDII datastream. Luckily most of the software/Apps that support the OBDII recording/logging are less than $50.

I still need to work out a good pass/fail system of the newer Wideband/Lambda O2 sensors that behave a bit differently, but hopefully I will have success with the Wideband/Lambda O2 sensors and be able to provide examples of these in the near future.

I consider what we are doing as trending, finger printing or gathering a signature of the O2 sensor performance for the E46. Similar testing can be done on other cars, however, the trend, finger print or signature may look slightly different.

Also the post-cat sensors can be tested and graphed in the same manner but they are a bit slower to respond and do not have swings that are as great. You can see the post-cat sensors on this graph are a bit in question, but for now on this specific car we are not too worried about the post-cat sensor response.

Probably more to follow as I have people submit additional data for review and I have a larger pool of data to compare against.
 

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Discussion Starter · #36 ·
Couple of updates following the DIY smoke test I performed this week end.

Good news is that I found and fixed a vaccum leak but with no change regarding my issue.

It appears that I completely failed during the dipstick O-ring replacement few months ago.
At that time I had a very hard time putting back the tube with new O-ring in the crankcase. I spent at least 30min of failed attempts so I ended up putting the O-ring in its place and gently pushed the dipstick tube until it went it (in fact it did torn the O-ring instead so I had only 3/4 of a O-ring during all that time)

So here is my tip for anyone who wants to know how to replace the dipstick O-ring, it took my only few seconds this time by doing it properly.
Take a thin piece of wood (approx 2feet long & 1 inch wide) and a mallet. Put the O-ring with some oil on it on the dipstick tube and then insert the dipstick on the crankcase until it stop.
Verify that it is well aligned and then put the piece of wood in the middle of the Y shape junction where the CCV return line joins the dipstick tube.
One and two mallet hits later, the dipstick should be back in place.

I did record a 250km trip prior to this O-ring replacement, but I don't know if it worth posting it since jfoj stated that only warm up O2 data are relevant for troubleshooting the sensors.

Anyway, I'm still chasing my issue so I ordered 2 new pre-cat O2 sensors, some Wynn's Hydraulic Valve Lifter treatment.
I plan to update my DME with latest software and I am also working on a microwave injector cleaning system.

I stumble on this thread recently, I might give it a shot as well since I have some of the symptoms : http://forum.e46fanatics.com/showthread.php?t=856781&page=15
 

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I did record a 250km trip prior to this O-ring replacement, but I don't know if it worth posting it since jfoj stated that only warm up O2 data are relevant for troubleshooting the sensors.
Warm Fuel Trim info is useful. Just values at idle and steady highway cruise.

O2 sensor graphing really needs to happen from cold start as you can see how slow the O2 sensors are to warm up and respond.
 

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Are you talking about STFT or LTFT ? Hope LTFT because my STFT are very unstable, even at steady RPM.
Mostly LTFT, STFT do move around a bit, I usually mentally average STFT, but I need to now if STFT is say jumping from +10-20% regularly or just jumping from say -5% to +5% as this is a bit different and may point to some other issues.

If you have a .CSV file you can shot me, then I can just look it over and analyze the info.
 
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