Emissions Error and Secondary Air Pump Setup Troubleshooting.

[Aronis]

Ok all first a disclaimer: Those who deleted their secondary air pump system please chime in with knowledge but I am not going to remove mine.

My last issue since my rebuild has been an error with the secondary air pump system. I have tried doing the usual trouble shooting and have not found the answer.

My mechanic suspects a leak in the vacuum system on a seal that sits between the brake master cylinder and the firewall.

What happens is than when I start the car the secondary air pump runs quite loudly. If I wait until it stops I do not get a CEL, but if I don't wait I get a CEL and the scan below. I replaced the solenoid and the actual secondary air pump and that did not fix the problem.

What we suspect is that when the car is being driven before the pump shuts down the vacuum is being use for other things and as a result there is not quite enough to open the combi-valves fully and I get the error. We suspect the combi-valves are only opening slightly, just enough to inject air into the exhaust for it's usual purpose, but not enough for efficient use of the flow and thus the pump sounds much louder. I am considering applying vacuum to the combi-valve with a syringe to see if the sound is different. Too bad the combi-valves are so hard to get at to remove and actually examine.

There is an associated error message about "Brake Boost Vacuum System" but the brakes feel fine.

We tried to make the secondary air pump run the test (block 77 if I recall) which is done by reving the engine to 2500 to 2600 RPM and holding the brake at the same time but the test wound not run on either bank.

I did the brake test for vacuum and that gave a correct reading.

The exhaust temp sensor thing is very intermittent especially since I did the re-solder thing.

So any input?

Thank you,

Mike

PS it's nice having A/C once again.


18048

[nubcake]

Silly question, but - do you actually want to fix the problem or just shut down the light? :)

If it's the former - properly inspect the whole N112/N249 vacuum system (it's actually a separate one from brakes).
There's a vacuum line on driver's side, routed near the PS reservoir. It goes from the fenderwell-mounted vacuum reservoir to the N249 (DV control) valve plumbing. If you let the car sit for a while, then disconnect the line - will it let the air in? I.e. will it produce a noticeable hissing sound?

If not - it's either one of the lines or check valve being at fault.
When driving off you pressurize (boost) the intake - and there's no more vacuum to keep combi valves open.

[Aronis]

Nubcake, Thanks for the input. I have looked at the entire vacuum setup from the reservoir to the combi-valves and cannot find a fault. When I disconnected the line to the control solenoid there was plenty of vacuum on the vacuum side.

I am not so sure about there no longer being vacuum after you drive off. The brakes depend on a supply of vacuum to 'assist' you when you push the peddle. I don't think the brakes rely on a 'reserve' of vacuum created in the few minutes of idle when you start your car LOL.

Shut down the light would be fine.....'code it out' I guess? I kind of want to find the problem since I don't want the brakes to give out suddenly.

Mike

[GreggPDX]

I think your theory about the combi valves not opening enough is valid. Do you have a Mityvac? you could use that to apply vacuum up at the solenoid under the engine cover. I think you previously mentioned you replaced that solenoid already, but you could try applying vacuum up there and see if the pump quiets down. That would back-up your theory of low vacuum.

I think the P1479 code is the key issue. You mention that the VAGCOM test passed, but I suspect the test passed because you were just sitting idle when you ran it. Like the air injection issue, it's OK if you aren't driving. That seems to point to a slow leak or weak booster pump.

First, I'd suggest a google search for CEL P1479, there are quite a few threads about the issue out there. Most seem to point at a vacuum leak or brake booster pump failure. I agree with nubcake that you need to check all the various vacuum lines and valves. The google threads describe what a lot of people look at as well. You mentioned your mechanic suspected a specific leak, has he tried to fix it?

[Aronis]

GreggPDX, we discussed the approach to that possible leak. It sounds like a few hours work and it may come to that kind of trial and error approach. The seal he was referring to is just an O ring.

I'll read up on CEL P1479.

Thank you,

Mike

[Aronis]

One thread ended up being a bad Suction Jet Pump which I replaced with a new one, but under my theory of a hell a new part can be bad, I hope it is not that. That Suction Jet Pump is a PITA to get to on the RS6. You have to remove the intake completely.

Mike

[nubcake]

SJP is exactly the reason why you get vacuum for brakes even under boost.
N249/N112 system is however connected directly to the manifold via a checkvalve.

Actually I haven't looked at the system for a long time now (and on top of that have a euro spec car in mind), so I might be mistaken. But it really makes perfect sense to me.
Re: just shutting off the diagnosis - if you decide to go this route, I'm going to need a readout of your current flash. This (http://www.ebay.com/itm/MPPS-V13-SMPS-K-CAN-Flasher-chip-tunning-ECU-Remp-OBD2-diagnostic-Cable-V13-02-/302105504880) can get it. PM me if you need further assistance with this.

[Aronis]

I went to get my car inspected today and it failed. At my milage I am allowed one "red" light on their scanner, but I have two linked issues which will not set to the "readiness." Those are the secondary air pump and the catalytic converters. I was told they are linked so if the first fails the second will also. I was able to get the EVAP to go to readiness.

So I took the intake off and inspected again. All the tubing is fine. I made a vacuum attachment so I could apply vacuum to the comb-valves directly and try to blow into the fitting by mouth.

18049

I wanted to quantify this better so I set up a pressure gauge and used my compressor to blow air in the combi-valve while my shop vac applied the vacuum. No flow into the combi-valves. I think they are both shot.

The car was cooled down a bit by the time I put it all back together but not cool enough to trigger the secondary air pump to run. I tried using VAG to trigger the "test" on block 77, and this time I was able to make the car rev to 2500 while depressing the brake but the test would not start.

I am going to let the car cool down overnight and start it up to see if the pump runs. I hit the comb-valves with a wrench a few times> Stuck or diaphragm gone, not sure. I could put an Allen Wrench on 4 of 4 on the driver's side but only 3 of 4 on the passenger side. I spoke with my mechanic and he is confident he can change both without dropping the engine.

I had the Combi-valves on my parts list last years. Should have done it. DAM IT! What 's another $600 in parts!

Mike

[AndyRS6]

I used this combination
18053
Work for me


Andriy

[AndyRS6]

And there are only 3 bolts on passenger side18054



Andriy

[AndyRS6]

Or are you talking about this one?18055



Andriy

[Aronis]

18056


One the passenger side there is one on the back I think that I could not get an Allen on. Are you saying the one in front is the only bolt on the bottom of it? That would be very nice! LOL


I have a similar cut off allen. LOL. They come in very hand. So is there only one on that side?

Mike

[Aronis]

18057

From my last service (cam tensioners). I can see one bolt in front. I am looking for a better photo. But if there is just one bolt, I can DIY.

Mike

[AndyRS6]

18058


Andriy

[Aronis]

18059

I see the bolts you are pointing to. Are you saying THOSE are the ones to remove instead of those directly on the bottom of the combi-valves? They look easier to get a wrench on. :)

It's funny I took a bunch of photos but did not really realized I should have taken more various subsystems up close. The passenger side is hidden behind a pair of metal tubes on my photos.

So if I remove these bolts and the other two on the back of the combivalve does the valve and the mount come out easily? Are there seals needed?

Mike

[Aronis]

PS I am pricing parts. Combivalve for 4.2 L v8 - $170, Combivalve for RS6 $270. WTF? How different could they be? bastards.

Mike

[nubcake]

PS I am pricing parts. Combivalve for 4.2 L v8 - $170, Combivalve for RS6 $270. WTF? How different could they be? bastards.

Mike

Are used ones out of consideration, if I may ask?
A lot of people delete those...

[AndyRS6]

18059

I see the bolts you are pointing to. Are you saying THOSE are the ones to remove instead of those directly on the bottom of the combi-valves? They look easier to get a wrench on. :)

It's funny I took a bunch of photos but did not really realized I should have taken more various subsystems up close. The passenger side is hidden behind a pair of metal tubes on my photos.

So if I remove these bolts and the other two on the back of the combivalve does the valve and the mount come out easily? Are there seals needed?

Mike

I remove combi valve with mount because I need more room. In your case I think would be better to remove combi valves only, but still you need to loosen all three bolts on passenger side to have enough clearance for one forward dolt on combi valve.
18062
You need paper gasket between cylinder head and combi valve mount ( 078131120M pass. 078131120E driver) and 4 metal for combi valve ( 078131120K )

Before you remove combi I would recommend to use brake fluid vacuum pump few times to see from inlet side if valve opens ( applied vacuum more than one time)
18063

Also did you check pump it self with hose removed to combi ( how loud it work)?




Andriy

[Aronis]

Andriy,

I applied vacuum directly to the system and confirmed my setup provided good vacuum. The pump is fairly quiet when disconnected, but very loud when trying to pump to combi valve.

I have not started the car since messing with it. When I finished buttoning things up and started the car the pump did not run as I suspect the car was still too hot. I was going to start it Saturday morning but got tied up painting a fence LOL. Now I am on a 40 day run of every other night call. :)

Nubcake,

I have not problem 'deleting' them, but more interested in knowing if I can just 'code them out' and just leave it not working and just get the thing to go to emission test Readiness state? Removing them and plating looks like the same amount of work/grief as replacing them. No?

I have no problem with used ones! Who has some for sale?

Mike

[AndyRS6]

Did you try to applied vacuum and spray carbon cleaner inside true inlet port. Sometimes it helps

[AndyRS6]

If you code them out, than you can block combi valve inlet side I think.
18064



Andriy

[Aronis]

Excellent....but will it fail inspection?

I have enough miles to allow for 2 failures. See photo. The EVAP was no problem, got that cleared and reset. I can trigger it's self test. I could not trigger the self test on the Secondary Air Pump.

18065

But I think the Secondary Air Pump test triggers the next test for the Cats. So before I go through such a process I need to be certain I'll pass inspection. I guess the coding out of the secondary air pump might trigger Readiness for that system?

Mike

[Aronis]

Do I have to take the intake pipe off the back of the combi-valve or just spray into the pipe at the secondary air pump connection?

Mike

[nubcake]

You can code out SAI in such a way that it will not throw a code and pass readiness (even with system completely gone).
Described here for example: https://s4wiki.com/wiki/Tuning#Secondary_Air_Injection (useless for a non-tuner, but it briefly explains the mechanism behind it).

That's why I asked initially about fixing the system or just the DTC/readiness.

[AndyRS6]

Do I have to take the intake pipe off the back of the combi-valve or just spray into the pipe at the secondary air pump connection?

Mike





You need to spray directly in to combi valve true intake pipe and applied vacuum ( that brake fluid vacuum pump $20 and easy to use if you need to applied vacuum and relies multiple times)
Also if you code them out you don't need to block combi valves (they're stuck in close position, just remove vacuum line from both sides and make a loop)



Andriy

[Aronis]

The question remains if the readiness of the Secondary Air Pump will show as Ready if I code it out. Otherwise I will still have TWO not ready (Secondary Air pump and Catalytic Converter) and still not pass inspection.

Mike

[Aronis]

Before you remove combi I would recommend to use brake fluid vacuum pump few times to see from inlet side if valve opens ( applied vacuum more than one time)


Andriy

Andriy,

I am not quite following you on this. Do I remove the connection at the back of the combi valve to spray? How much space would I then have to spray directly into the valve? The piping on the back of the valve is rigid from what I can see? Flex out?

Thank you,

Mike

[AndyRS6]

Andriy,

I am not quite following you on this. Do I remove the connection at the back of the combi valve to spray? How much space would I then have to spray directly into the valve? The piping on the back of the valve is rigid from what I can see? Flex out?

Thank you,

Mike[/QUOTE]




Yes, you need to remove connection at the back.
You can push pipe away, or remove completely, only one bolt holding in the middle and two bolts at the combi valve (both sides), and one clamp by pass. combi, or from SAI pump.
18068180691807018071
Also very good tool for $20, if you want to check inside.
I would recommend
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Andriy

[nubcake]

The question remains if the readiness of the Secondary Air Pump will show as Ready if I code it out.

I probably was not clear enough: depends on how it is "coded out".
It can be made to show "ready", yes.

[Aronis]

Nubcake,

Thank you very much, that is a great diagram. I am just kicking myself for not swapping those out when the engine was out. But had to stop at some point.

Mike

[Aronis]

Update: Parts are in. One came from Germany, came pretty quickly!. I have to wait until Wednesday to run up to dealer to get parts and drop off at the mechanics place. Hopefully he will have time to finish it this week.

Mike

[Aronis]

New parts. Go in tomorrow...hopefully back on the road by Friday.


18100

[Aronis]

New EGRs are in. It took less than 3 hours.

But it still did not work. Now my new pump has sprung a leak! Probably from pushing against closed valves. Next is the Vacuum system. He suspects not enough vacuum to open the valves?

Should have driven the car with the friggen oil leak and just added oil every week. !

Mike

[Aronis]

So new EGRs are in. System would not pass with vagcom triggered test. But when run stone cold pump ran and secondary passed. And readiness was set.

In our effort to figure out WTF is with the test which runs with car at 2500 rpm we found what appears to be insufficient vacuum to open EGR. Got -100% for reading on the secondary pump test and failure. Applied clamp to keep vacuum leak suspected at firewall from causing trouble then reran test. Still -100%. Then applied vacuum by hand pump directly to EGR. Ran test. Got -32%. Still failed but better.

So is the vagcom triggered test really correct for this model year??

Tomorrow with engine cold he's going to run engine and see if test runs at idle and if readiness is set I'm all set. Pass inspection. I replace pump and ERGs but not sure if either was needed. Both old EGRs appear to work.

Oh well

[Aronis]

Update:

Backup. Changed Solenoid, worked fine for a week without CEL. Then failed. Changed Pump, was very loud, still threw CEL. Car would not run diagnostic on secondary air pump system. Replaced EGR valves. Old ones were a bit stiff but actually open under vacuum. Still no go. Replaced new secondary air pump with new one (first one actually fell apart and leaked a lot LOL). No go.

Now we put a pressure gauge on a T in line with the vacuum on the down side of the Solenoid. NO VACUUM! WTF!?!?

Now the ECU is out and next step (tomorrow) is to check continuity from the Pin 44 back to the solenoid. I may be just a friggen loose wire. Spent $1200 on friggen parts for perhaps nothing. Friggen car......

Mike

[nubcake]

Spent $1200 on friggen parts for perhaps nothing. Friggen car......

That's why it's a bad idea to throw parts at it. :)
Proper diagnosis is the key.

Is there vacuum upstream?
Are you 100% your ECU software is stock?

[Aronis]

LOL. It's bone stock buddy! I am the original owner. There is vacuum.

The problem is that there appears to have been more than one issue. When we directly applied vacuum (-15 ) to the original EGR valves and fired up the air pump it still sounded like it was pumping against closed valves. With the new EGR valves doing the same thing the toned changed and the pump sounded normal again (you can hear it but not from the next block away). So I really think the old EGR valves were stuck. Once out of the car and worked manually a few times they then functioned with vacuum applied. So basically they needed to be cleaned but not replaced I guess.

The original pump got loud as it was pumping against closed EGR valves. That is about when it threw the CEL.

So FYI to others......the car uses ground to control things at the ECU. So at the Solenoid you'll always find Plus 12 to 14 volts. The ECU switches out the ground. I was not aware that is how the car's systems are switched on and off. That way the ECU is not the source of out flowing current so there is not much load across the ECU but rather just switches the ground path on or off. So a short can't fry the ECU I guess. IE if the ECU was the source of switched current to a circuit and a wire was shorting to ground at the other end, the ECU would get fried.

Pin 44 is the input at the ECU so we are going to determine if there is an open circuit some where between the ECU and the solenoid. IE A broken wire. Friggin old car. LOL.

If that is the problem then should be fixed shortly and back on the road.

Yes, I don't like throwing parts at the system but I also don't like spending $100 an hour on labor.

Mike

[Aronis]

18160

The cause. $0.10 parts

Mike

[Aronis]

It's fixed!

Passed tests.

[Aronis]

Back on the road, drove right to the inspection station (already paid the 21 bucks a few weeks ago) to get the sticker quick before something else shits the bed.

I have to scan to see if the other failure is still there.

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Mike