brand new user....i've owned a couple of A4s an
Audi 90 and now a 2003 allroad. Just picked this car up very cheap. 165k miles single owner dealer maintained. He gave me all the records with the car. it was a good deal. 2 grand cash. I was psyched!

I just installed the Arnotts and the Bilsteins and the pump. Suspension is fine now. Runs great and has lots of power.

The bad is that the CEL is persistent even after clearing the codes.
I'm getting the following:

2 Faults Found:
17862 - Exhaust Gas Temp Sensor 1 (G235): Short to Ground
P1454 - 35-10 - - - Intermittent
17819 - Secondary Air Injection System; Bank 2: Insufficient Flow
P1411 - 35-00 - -


Now the question lies herein: When I start the car I can hear the air pump come on. It's noisy... however, it's not like the screaming jet engine type others have experienced. It's more like a noisy exhaust. Before I researched any of this and before I knew what the SAI system was for I thought there was an exhaust leak. After learning of the pump issues I pulled it, and ran leads from the battery straight to the posts. It seemed to run fine and not only that,it didn't sound noisy.


When I tried to set readiness I fail emissions due to one of the cats not getting to temperature and when it forces the SAI to come on, I can hear the pump start but then it fails the test.

After going through the dealer invoices I found that they had just replaced the pump, the hose and the valves 8k ago. I asked if they would warranty the part but told me it was over a year ago so screw off basically.

So my question is two fold: First would the valves (or something else in the SAI system)be causing the noisy "leaky-exhaust sound" that I am experiencing rather than it being the pump? And second, if I am getting the insufficient flow code, could this also be duping the EGT sensors? or vice-versa?

Lastly, when monitoring the cylinders I continually get misfires on cylinder #6. Is it misfiring because of the EGT's? Or does it seem more like a bad coil since it's only the 6th cylinder?

Thanks in advance.

I will check the vacuum lines from pump and from the valves as well.
Could the pump if failing cause the noise? Also when checking the blocks 74 and 75 for SAIP I get a zero reading.

anyone?

I will check the vacuum lines from pump and from the valves as well.
Could the pump if failing cause the noise? Also when checking the blocks 74 and 75 for SAIP I get a zero reading.

Have you activated the air pump using the output diagnostic test mode (function 3)? The combination valve have not have been correctly installed or the gaskets slipped as this area of the engine is hard to work due to limited space for persons with large hands and also if they are working against the clock. I have seen many examples of dealership "collateral damage" on 2.7l turbos and other V6 engines. The worse was blowing up a new replacement Allroad 2.7l turbo because the oil cooler was not replaced with the new engine when the old engine had failed due lack of oil from a road debris impact that broke the oil pan.

When I had my 01 a6 2.7t I had a similar problem with the combi valves.
I removed them from the engine and then cleaned them out with brake clean.
My codes were coming up due to a build up in the valves. you can try cleaning them out it may help.

Thank you both peter and "01 2.7t"

I have activated the pump using the diagnostic and disconnected it from the
combi valves as I did. It was like a jet pump! The pump seems fine to me.
According to the records Audi replaced all of these components a year ago.

On one side the test Aborts and on the other I get a negative reading.

The interesting thing Peter is that on the pass side, the combi valve seems to have oil leaking around the gasket and I have some smoking on that side as well. Perhaps I try to get those valves out, clean them and replace the gaskets?

Thanks to both of you. One last thing. I have been driving with the pump simply disconnected to save it if those valves are clogged or failed, however I still get that strange exhaust leak sound on cold startup. any ideas why that would be?

Mines been unplugged for 2 years. I live with the CEL and scan the car monthly to see if any new codes are present. I am waiting to get a custom tune to delete the SAI pump and then I will remove it and all components. Mine sounds like a dying drill when it's plugged in and its embarassing.

My car at startup has a different sound for about a minute which is about how long the SAI pump runs. I think the valves just open although the pump isn't pumping any air into the exhaust.

The whole system is pointless. The purpose of it is to add air into the cold engine to reduce cold start emissions. The engine runs richer when it's cold and by adding air to lean out the mixture apparently its less harmful to the ozone.

Any state that does emission testing, tests the cars when the engine is warmed up to normal operating temperature. So the system isn't needed. No other cars I'm aware of besides the Audi 2.7t engines w/ tiptronic transmissions have this type of system.

Once removed and tuned out, it will still pass emissions as long as you don't have bad cats or O2 sensors. My friend has a Vast Stage III tiptronic S4 and he has removed and tuned out the SAI pump and system. Car runs strong, has no cats either, and no CEL's since his SAI, rear O2's, and EGT's are coded out of his tune.

Scott

Thanks. that makes a lot of sense. I appreciate your addressing that noise on startup. That's part of what I want to understand. If the pump isn't pumping air into the system why am I getting that throaty exhaust noise? Good to know that yours does the same.

Any idea where or what the sensor is that actually measures the air flow into the combi valves? And if I have a negative reading would that mean that the combi valve simply isn't opening? Still searching for info on this... will let you know what happens. slow process.

Scott

Thanks. that makes a lot of sense. I appreciate your addressing that noise on startup. That's part of what I want to understand. If the pump isn't pumping air into the system why am I getting that throaty exhaust noise? Good to know that yours does the same.

Any idea where or what the sensor is that actually measures the air flow into the combi valves? And if I have a negative reading would that mean that the combi valve simply isn't opening? Still searching for info on this... will let you know what happens. slow process.

There isn't a sensor to measure air flow to the combination valves. The ECU
uses changes in the O2 sensor readings to check for flow from the SAI for each cylinder bank separately. Both flow tests and then leak tests are checked in this manner. The Audi self study program booklet for OBD2 diagnostics describes these tests more fully.