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Old 07-14-2017, 10:53 PM   #1
nebula
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Secondary Air Fault

I'm currently diagnosing a Secondary Air Fault using this diy:
https://blog.bavauto.com/12072/bmw-s...to-diy-obd-ii/

The air pump turned on for about a minute on a cold start. I didn't feel significant coming or going from the check valve. Later in the day I tried using a mityvac to actuate the valve and I still didn't notice any significant suction or pressure from the check valve. The hose from the valve to the pump appears to be saturated in grease.

I yet to test the vacuum lines, but my current suspicion is that the valve is bad.

Can anyone tell me if the hose being soaked in grease a symptom of a larger problem?

I don't remember the exact codes but I will update this post when I have written them down.
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Old 07-15-2017, 05:38 AM   #2
jfoj
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The SAP pump can have the impeller spin on the shaft, so the pump can run but little to no air will move.

If hose that connects between the SAP pump and Kombi valve on the cylinder head has standard hose clamps, disconnect the hose and check for deterioration inside the hose and see if any part of the hose actually clogged the Kombi valve.

I assume you are getting the codes P0491/P0492??
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Hidden OBC Menu - Check Voltage, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

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Lower hose temp switch O-ring - BMW #13621743299
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Old 07-15-2017, 06:08 AM   #3
nebula
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Quote:
Originally Posted by jfoj View Post
The SAP pump can have the impeller spin on the shaft, so the pump can run but little to no air will move.

If hose that connects between the SAP pump and Kombi valve on the cylinder head has standard hose clamps, disconnect the hose and check for deterioration inside the hose and see if any part of the hose actually clogged the Kombi valve.

I assume you are getting the codes P0491/P0492??
Thank you for chiming in.

Yes the error codes are P0491 & P0492

Just for clarification the secondary air pump ran on cold start up and I felt significant air flow coming from the pump. I tried and did not feel any suction or pressure from the check valve even when trying (later after warm up) to actuate it using a mityvac.

I removed the hose but I didn't inspect the interior of it. I can try again in the morning. Like I said previously the hose is saturated in what appears to be engine oil so I will be buying a replacement. I believe its 11727555680.
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Old 07-15-2017, 06:12 AM   #4
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The Kombi valve can stick and they can also get debris from the inside of the supply hose deteriorating.

These codes can also occur if the Pre-cat O2 senors are lazy. This is not uncommon. Chances are the car has the original O2 sensors installed as well.

Here is some light reading for you:

http://forum.e46fanatics.com/showpos...&postcount=154

http://forum.e46fanatics.com/showthread.php?t=1041726

http://forum.e46fanatics.com/showthread.php?t=1023149

http://forum.e46fanatics.com/showthread.php?t=965526

http://forum.e46fanatics.com/showthread.php?t=1052605

http://forum.e46fanatics.com/showthread.php?t=1074847

http://forum.e46fanatics.com/showthread.php?t=1074573

http://forum.e46fanatics.com/showthread.php?t=106959

http://forum.e46fanatics.com/showthread.php?t=1074847

http://forum.e46fanatics.com/showthread.php?t=106959

http://forum.e46fanatics.com/showthread.php?t=1078986

http://forum.e46fanatics.com/showthread.php?t=1096889

http://forum.e46fanatics.com/showthread.php?t=1100895

http://forum.e46fanatics.com/showpos...2&postcount=28

http://forum.e46fanatics.com/showpos...7&postcount=29

http://www.bimmerfest.com/forums/sho...ary+air+system

http://www.bimmerfest.com/forums/sho...d.php?t=430048

http://forum.e46fanatics.com/showthread.php?t=1125815
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Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491

Hidden OBC Menu - Check Voltage, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

E46/E39 GM5 Door Lock Info - www.bmwgm5.com

Lower hose temp switch O-ring - BMW #13621743299
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Old 07-15-2017, 06:35 AM   #5
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Thank you I had read over a few of these already prior to creating the post. I just read over the rest. I will try graphing the O2 sensors in the morning as well as checking the kombi valve.

I'm still wondering why the pressure hose was saturated. I didn't see any mention of this in other posts. Is this normal for this age or could it be a larger problem?
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Old 07-15-2017, 06:39 AM   #6
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The SAP hose should not be covered in oil, not sure why this is, I do not recall ever seeing this as a problem.
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Fuel pump failures - http://forum.e46fanatics.com/showthread.php?t=929501

Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491

Hidden OBC Menu - Check Voltage, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

E46/E39 GM5 Door Lock Info - www.bmwgm5.com

Lower hose temp switch O-ring - BMW #13621743299
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Old 07-15-2017, 06:45 AM   #7
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Thanks.
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Old 07-15-2017, 07:28 AM   #8
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Check and verify the cheap fixes first. If the 3 fuses are good, inspect the vacuum line that runs around the back of the engine. Replace the rubber line that runs from the plastic hose into the valve on the back of the manifold. You can also replace the piece that goes from the kombi valve to the front end of the plastic hose. Total is <$5 and 1/2 an hour of your time to pull out the cabin filter tray. I had the 491/492 code set 2 weeks ago and it was the vacuum line in the back.
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Old 07-15-2017, 10:26 PM   #9
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Tried checking the kombi valve again this morning. On first startup I did did not feel any suction or pressure again. I tried hooking up the mityvac to the kombi valve and I did notice a gurgling sound coming from the kombi valve but still no suction or pressure. Holding a finger on the vacuum hose that I had disconnected I notice minor suction. I completely forgot to do the O2 sensor graph and I will try that tomorrow.

Last edited by nebula; 07-16-2017 at 01:23 AM.
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Old 07-16-2017, 07:28 AM   #10
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Since you have a Mityvac, after a cold start Log with everything connected as it should be, run another cold start Log the following morning with the Mityvac connected to the Kombi valve with a full vacuum applied before you start the engine.

This will quickly allow you to compare the 2 Logs to determine if there is a vacuum control problem to the Kombi valve.

The vacuum hose to the Kombi valve is a known problem for failure, but lazy O2 sensors and other problems are also quite common.
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Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616

Fuel pump failures - http://forum.e46fanatics.com/showthread.php?t=929501

Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491

Hidden OBC Menu - Check Voltage, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

E46/E39 GM5 Door Lock Info - www.bmwgm5.com

Lower hose temp switch O-ring - BMW #13621743299
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Old 07-16-2017, 12:49 PM   #11
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First attempt at logging. Please let me know if I did this right.
Thank you for your help!

https://drive.google.com/file/d/0B22...ew?usp=sharing
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Old 07-16-2017, 01:07 PM   #12
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Quote:
Originally Posted by jfoj View Post
The vacuum hose to the Kombi valve is a known problem for failure, but lazy O2 sensors and other problems are also quite common.
This is true. I had the SAP emissions monitor not completing, so I couldn't get it smog tested. After verifying each component of the SAP system was working properly, I did a cold start log and found that the bank 2 precat O2 sensor was performing poorly; obvious in the graph comparing it to the bank 1 precat O2 sensor.

Replaced both precat O2 sensors and did another cold start log. It was obvious that the new sensors were performing well and that solved it. This was in my E39 (2002 530i) with the same M54 motor and MS43 DME as many E46s have.

It's a good lesson in OBD trouble codes. They're simply clues. You have to diagnose things carefully and assume nothing.
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Old 07-16-2017, 01:17 PM   #13
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Quote:
Originally Posted by nebula View Post
First attempt at logging. Please let me know if I did this right.
Thank you for your help!

https://drive.google.com/file/d/0B22...ew?usp=sharing
A few issues:

1. You ONLY had 1 O2 sensor set to Log. I see you are using Torque, it is slightly different than OBDFusion but you should be able to set all 4 O2 sensors to Log.

2. I need to look at all the O2 sensors Logged, but on first glance it appears that the SAP may be working, but there is a delay in getting the air into the exhaust either due to a valve leak in the control system or the Kombi valve is sticking.

3. I could tell easily if the problem is in the vacuum control system if you put the Mityvac on the Kombi valve before you start the engine and then pull a vacuum, this would simulate a good control vacuum on engine cold start.

4. It could be an issue of the O2 sensor wiring being spliced and connected wrong, can you tell of the O2 sensor wiring ever appears to have been repaired or spliced??
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Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616

Fuel pump failures - http://forum.e46fanatics.com/showthread.php?t=929501

Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491

Hidden OBC Menu - Check Voltage, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

E46/E39 GM5 Door Lock Info - www.bmwgm5.com

Lower hose temp switch O-ring - BMW #13621743299
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Old 07-16-2017, 02:33 PM   #14
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My apologies on the config. This is what I had setup this morning



Starting at line 230 I thought there was readings for the second sensor. I will reconfigure and try with all 4 sensors and use the mityvac tomorrow.

I'm not really sure where the O2 sensors are located but I will figure that out and check the wires.
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Old 07-16-2017, 02:47 PM   #15
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I just read that you recommended clearing the PID list and re-adding everything in another thread so I am going to try that.
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Old 07-16-2017, 03:49 PM   #16
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What App are you using? Torque??

Spend the $3.99 and get OBDFusion, far more stable than Torque IMHO.
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Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616

Fuel pump failures - http://forum.e46fanatics.com/showthread.php?t=929501

Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491

Hidden OBC Menu - Check Voltage, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

E46/E39 GM5 Door Lock Info - www.bmwgm5.com

Lower hose temp switch O-ring - BMW #13621743299
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Old 07-16-2017, 05:59 PM   #17
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Quote:
Originally Posted by jfoj View Post
What App are you using? Torque??

Spend the $3.99 and get OBDFusion, far more stable than Torque IMHO.
Will do.
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Old 07-16-2017, 06:42 PM   #18
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OBDFusion installed. Setting up logging. When selecting PIDs I should select:
O2 voltage bank 1 sensor 1
O2 voltage bank 1 sensor 2
O2 voltage bank 2 sensor 1
O2 voltage bank 2 sensor 2
RPM

Any other sensors? I'm not seeing bank 3 or 4.
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Old 07-16-2017, 06:55 PM   #19
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Quote:
Originally Posted by nebula View Post
OBDFusion installed. Setting up logging. When selecting PIDs I should select:
O2 voltage bank 1 sensor 1
O2 voltage bank 1 sensor 2
O2 voltage bank 2 sensor 1
O2 voltage bank 2 sensor 2
RPM

Any other sensors? I'm not seeing bank 3 or 4.
There are only two banks haha. Bank 1 (cylinders 1-3) and bank 2 (cylinders 4-6)
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Old 07-17-2017, 01:21 AM   #20
nebula
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There are only two banks haha. Bank 1 (cylinders 1-3) and bank 2 (cylinders 4-6)
did I mention I'm new here?
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