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Tumbler510
09-26-2018, 09:57 PM
After troubleshooting a few issues in the $300 A4, I finally got it down to only P1127 & P1141. I did a bit of research and some people point to the secondary air pump being bad, throwing the code.

I took a video of mine in action after a cold start. The link is below.
Notes:
- car is cold
- pump stars on for the entire 1min+ video (would stay on longer)
- pump sounds like a jet engine after engine shut down
- no leaks observed in outlet hose

Any idea if the pump itself is bad?

https://m.youtube.com/watch?v=a0i1kWFhtro

fR3ZNO
09-27-2018, 05:30 AM
Typically if the SAI pump is bad you'd have a P0411 (http://wiki.ross-tech.com/wiki/index.php/16795/P0411/001041)code (SAI incorrect flow).

Looking at the codes you posted, I would think there's an issue other than the SAI pump. What research did you do that led you to think it was the SAI pump?

17535/P1127/004391 - Fuel Trim; Bank 1 (Mult): System too Rich
(http://wiki.ross-tech.com/wiki/index.php/17535/P1127/004391_-_Fuel_Trim;_Bank_1_(Mult):_System_too_Rich)

17549/P1141/004417 - Load Calculation Cross Check: Implausible Value
(http://wiki.ross-tech.com/wiki/index.php/17549/P1141/004417)

IMO, after watching the video, your pump sounds okay. They usually make some amount of noise when running, the "jet engine" sound that indicates it being bad is normally much louder.

BigBan
09-27-2018, 06:20 AM
Would you please like it

Tumbler510
09-27-2018, 08:00 AM
Looking at the codes you posted, I would think there's an issue other than the SAI pump. What research did you do that led you to think it was the SAI pump?

17535/P1127/004391 - Fuel Trim; Bank 1 (Mult): System too Rich
(http://wiki.ross-tech.com/wiki/index.php/17535/P1127/004391_-_Fuel_Trim;_Bank_1_(Mult):_System_too_Rich)

17549/P1141/004417 - Load Calculation Cross Check: Implausible Value
(http://wiki.ross-tech.com/wiki/index.php/17549/P1141/004417)

Basically a lot of searching around the forums. I found 2 minor hose leaks, fixed them, and the code stayed off until the "2A" readiness code was the only one left.

I did a DIY smoke test with a HF fluid transfer pump and a cigarello. I removed the MAF hose, plugged it with a towel, and ran the tube into it. I didn't see any smoke leaking out at all, and when I removed the towel, there was a lot of thick smoke in there. Should I try again with the TB open or some other valve activated?

Bank 1 is the passenger side. Is there a valve that I can check?
Bank 2 (drivers side) has a slight oil leak, so I was thinking it could be that.

What else should I be checking before replacing the SAP?

Edit: I have VAG-COM if that helps

fR3ZNO
09-27-2018, 09:40 AM
Basically a lot of searching around the forums. I found 2 minor hose leaks, fixed them, and the code stayed off until the "2A" readiness code was the only one left.

I did a DIY smoke test with a HF fluid transfer pump and a cigarello. I removed the MAF hose, plugged it with a towel, and ran the tube into it. I didn't see any smoke leaking out at all, and when I removed the towel, there was a lot of thick smoke in there. Should I try again with the TB open or some other valve activated?

Bank 1 is the passenger side. Is there a valve that I can check?
Bank 2 (drivers side) has a slight oil leak, so I was thinking it could be that.

What else should I be checking before replacing the SAP?

Edit: I have VAG-COM if that helps

Oh, so it's a V6.

With VAG-COM you can a SAI test separate from the set readiness procedure, I believe it is under basic settings or measuring blocks. Should tell you if the SAI is good.

Tumbler510
09-27-2018, 09:50 AM
Oh, so it's a V6.

With VAG-COM you can a SAI test separate from the set readiness procedure, I believe it is under basic settings or measuring blocks. Should tell you if the SAI is good.

Yeah its the 2.8 V6. forgot to include that.

Ok, i'll try that after work today.
So the issues could be:
- SAI
- Spark plugs
- Injectors
- N80
- Coils
- MAF
- Boost Leak
- O2 sensors

Any way to drill down into these instead of throwing money at it?

fR3ZNO
09-27-2018, 10:24 AM
Yeah its the 2.8 V6. forgot to include that.

Ok, i'll try that after work today.
So the issues could be:
- SAI
- Spark plugs
- Injectors
- N80
- Coils
- MAF
- Boost Leak
- O2 sensors

Any way to drill down into these instead of throwing money at it?

Well, we can cross boost leak off the list since it's a 2.8 [:p]

Tumbler510
09-27-2018, 10:27 AM
Lol. Good call.

I meant it more as "general leak test." Which I think would be helpful. But don't know how to properly do that with all the air paths open at the same time with the engine off.

fR3ZNO
09-28-2018, 11:44 AM
See responses in red.


Yeah its the 2.8 V6. forgot to include that.

Ok, i'll try that after work today.
So the issues could be:
- SAI

The SAI system is fairly simple consisting of a relay, air pump, inlet and outlet hoses, combi valves and vacuum lines. Since the air pump is coming on, we can rule out the relay. You said you checked the inlet and outlet hoses for leaks, so that's good. The combi valves can gum up with carbon. One way to check that would be manually apply vacuum with a hand pump or similar tool and then try blowing through the outlet hose (disconnect from pump). Finally, check the vacuum lines for cracks, tears, since the factory ones made from rubber can degrade over time. Very common to need replacement.

- Spark plugs

Could double check your spark plug gap and verify that they are all getting spark. If they're not then look into the coil pack and/or wires.

- Injectors

These are a little tougher to check, would require pulling them from the fuel rail and seeing what volume you get in a certain amount of time, basically determine the flow rate. Another parameter to check would be the fuel pressure at the rail with a gauge, cheap from Harbor Freight.

- N80

This would be your purge valve for the EVAP system. Typically if this is bad it will throw it's own code or a EVAP leak code. But worth checking to see if it's stuck open which would allow fuel vapors into the intake and cause your rich code.

- Coils

See above regarding spark plugs. Just to clarify, the 2.8 has a coilpack, not individual coils like the 1.8T and later 3.0 engines.

- MAF

See this Rosstech article on fuel trims, which touch on MAF values, very helpful: Clicky Click (http://wiki.ross-tech.com/wiki/index.php/Fuel_Trim_Info) The TL;DR version is to log a WOT pull in 2nd or 3rd gear and see what the peak MAF value is, it should be in the ballpark of 80% of your rated HP, for example, 190 hp 2.8 should see about 150~ g/s for MAF values. A number far from that may indicate an issue with the MAF.

- Boost Leak

Like mentioned earlier, wouldn't be exactly the same as a boost leak test like you'd do on a 1.8T, but it would still be good to check for any air leaks in the vacuum system and intake tract.

- O2 sensors

If these failed completely, they should throw a specific heater circuit code or no response. But one thing to note is that an exhaust leak before the pre cats could also cause the car to run rich (O2 sees more air than car is actually getting and ECU compensates for "false air" with more fuel, thus causing a rich condition).

Any way to drill down into these instead of throwing money at it?

Tumbler510
09-30-2018, 09:53 AM
Spark plugs on bank 1 seemed not 100%, so I swaped some newer ones in.
Should the code go away on its own or do I need to reset the codes and start over?

Is there a VCDS block I can check for the O2 sensor to see if its reading like there is a hole in the exhaust?

Tumbler510
09-30-2018, 10:01 AM
aggggg I just reran the codes, and it's P1141 and P1129 NOT P1127....

Avant Nate
09-30-2018, 07:37 PM
You can rebuild the SAI pump for a couple bucks. I did it on my wife's allroad. Hers sounded a little worse than yours though. bearings are 608.

https://www.audiworld.com/forums/a6-s6-c5-platform-discussion-7/writeup-2-7t-secondary-air-injection-sai-pump-rebuild-1727056/page2/

Tumbler510
10-01-2018, 08:06 AM
On the note about the air leak....somehow I assembled the exhaust without using a gasket between the exhaust manifold and the exhaust piping.
I ordered QTY2 new units, and will install them this afternoon.

Still not sure if I should reset the codes and start the cycles over again, or leave it and drive it until the ECU recognizes the car is not experiencing the same rich situation.

Tumbler510
10-03-2018, 05:59 PM
Update:
- Installed exhaust flange gaskets
- Reset codes
- P1141 came back
- "2A" went through it's readiness parameters MUCH quicker this time.
- Only "C" and "EV" are left flashing

MAF
- Removed rear insulation on MAF
- Plugged in DMM to all 3 plugs (black w/blue stripe, yellow, green)
- W/ car off, resistance against ground was: 101, 5, 2.9k
- W/ car idling, resistance against ground was: OL, 310k, 2.0M
- W/car throttling, Green wire resistance fluctuated with throttle position
- I believe this shows the MAF is in good working order and the readback signals are making it thru the connector sucessfully

OTHER
- PVC breather hose from front of passenger bank to valve on rear drivers side of engine was taped together. I removed it and pressure tested it with my mouth. No leaks. Removed tape. Glued. Retaped.

I want to check the MAP sensor now, but have no idea where is it.
I assume its under all the vacuum hoses at the rear of the engine, near the TB.
Can somebody please confirm?

Tumbler510
10-04-2018, 08:27 PM
OK cool...

I did some more research on the measuring blocks in VCDS.
Following this guide (https://forums.vwvortex.com/showthread.php?1265064) I took some screenshots when the car was at idle, after the SAI went off.

Image 1: Values for Block 030 show B1S2 and B2S2 fluctuated between "010" and "110." Not "111"
https://i.postimg.cc/Vvmc1s1Y/image.png

Image 2:
https://i.postimg.cc/VvgPNyLX/image.png


Image 3: Block 33 field 1 is "-16.4%" and I believe it should be between "-10" and "10" under proper operating. Showing it's reading rich...
https://i.postimg.cc/3rFT1GCW/image.png


I think this points to either the O2 sensor being bad, and reading rich, or something else...right?

fR3ZNO
10-05-2018, 12:21 PM
Looking through your screen caps, both pre cat O2's (b1s1 and b2s1) appear to be okay according to VCDS. However the rear O2's haven't gone into 111 status (ok). Did group 036 ever show the B1S2 and B2S2 status to be OK?

Your code that you pulled P1129 is for closed loop fueling not achieved for bank 2. So I don't suspect the rear O2's being bad right off, typically there'd be other codes pointing to the sensor health...

Just out of curiosity what kind of readings are you getting from your coolant temp sensor? Sometimes those can read incorrectly and cause rich running, although that would be on both banks.

Tumbler510
10-05-2018, 02:24 PM
Looking through your screen caps, both pre cat O2's (b1s1 and b2s1) appear to be okay according to VCDS. However the rear O2's haven't gone into 111 status (ok). Did group 036 ever show the B1S2 and B2S2 status to be OK?

Your code that you pulled P1129 is for closed loop fueling not achieved for bank 2. So I don't suspect the rear O2's being bad right off, typically there'd be other codes pointing to the sensor health...

Just out of curiosity what kind of readings are you getting from your coolant temp sensor? Sometimes those can read incorrectly and cause rich running, although that would be on both banks.

Thanks for the feedback. I'll have to check the measuring block for coolant temp sensor tomorrow.

I was getting all of the codes before, and then I fixed a few issues, reset the codes, and by the end of the last readiness cycle only P1141 was left. I am hoping that means the others were fixed.

Tumbler510
10-08-2018, 01:10 PM
Bump.

Does anyone know where the MAP sensor is for the 2.8?
It does have one, right?

walky_talky20
10-09-2018, 07:20 AM
No MAP sensor on the 30-valve 2.8. Just a MAF.

I just read this thread. It looks like you are running quite a bit rich. This is somewhat unusual as, generally speaking, the various vacuum leaks, dirty MAF sensors, worn fuel injectors and things you find on an aging Naturally Aspirated EFI car more often result in a lean condition.

That said, we should think about the types of things in general that could have such a dramatic effect on the EFI system that it would run so noticeably rich. We should be aware that the sensors that have the most control over fueling quantity are the air metering device (in this case a MAF) and the coolant temperature sensor. Some possible causes for a rich condition:

- Faulty or incorrect ECU
- Fuel injectors larger than stock
- Fuel Pressure too high
- Oxygen sensors falsely reporting a rich condition where none exists
- Coolant temp sensor falsely reporting engine temperature colder than actual, causing excess enrichment
- Air Metering Device (MAF) reading incorrectly (too high)

I've tried to list these in order from least likely (faulty ECU) to most likely (faulty MAF), in my own opinion. Please note, my opinion is not that of an expert and should not be relied upon - see my signature.

fR3ZNO
10-09-2018, 07:36 AM
see my signature.


"You need to know what you are doing...Its like a rainbow jungle in there." - Redline380

[>_<]

Tumbler510
10-09-2018, 08:44 AM
No MAP sensor on the 30-valve 2.8. Just a MAF.

I just read this thread. It looks like you are running quite a bit rich. This is somewhat unusual as, generally speaking, the various vacuum leaks, dirty MAF sensors, worn fuel injectors and things you find on an aging Naturally Aspirated EFI car more often result in a lean condition.

That said, we should think about the types of things in general that could have such a dramatic effect on the EFI system that it would run so noticeably rich. We should be aware that the sensors that have the most control over fueling quantity are the air metering device (in this case a MAF) and the coolant temperature sensor. Some possible causes for a rich condition:

- Faulty or incorrect ECU
- Fuel injectors larger than stock
- Fuel Pressure too high
- Oxygen sensors falsely reporting a rich condition where none exists
- Coolant temp sensor falsely reporting engine temperature colder than actual, causing excess enrichment
- Air Metering Device (MAF) reading incorrectly (too high)

I've tried to list these in order from least likely (faulty ECU) to most likely (faulty MAF), in my own opinion. Please note, my opinion is not that of an expert and should not be relied upon - see my signature.

Interesting ideas. Is there a way to test each in VCDS so I can narrow it down?
I replaced both rear O2 sensors last weekend since the rears were not giving "111" (OK) in VCDS, but they still don't give that now.

How can I check the ECU itself?

walky_talky20
10-10-2018, 05:35 AM
I would start with the easiest things that don't require getting dirty:

- Log the MAF value on a pull from 1500 to red line. Wide open throttle. Flat ground. Held in 3rd gear if possible.
- Look at the coolant temp value during important times: after a cold soak, during initial warmup, at operating temp doing whatever causes maximum fuel trims.