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Secondary Air Injection

jonathanA4 Oct 19, 2004

  1. jonathanA4

    jonathanA4 New Member

    So here's the story. My Secondary Air Pump, started making a weird noise the other day near the end of it's cycle after a cold start, it finished running and then shutoff as usual. The next day though the check engine light came on (no strange noises from the pump though).

    I figured the pump has bit the dust so I took it to my mechanic, sure enough the error code was 'Secondary Air Injection' but he said from what he saw it seemed to be pumping air still and maybe some debris got caught in it or something. He said maybe bring it in when I have more time and he can try it on a cold start to diagnose it a bit more (haven't done that yet). So he cleared the code and it seemed to be okay, but three days later the check engine light has come on again and I'm 100% sure it's the pump.

    Now here's what I'm wondering before I have him check it out again and possibly have to get a new pump put in. Is it advisable to bypass the secondary air system? It would slow the heating of the cat converter and cause worse emissions on startup, yes - but would it damage anything? It's an expensive part if it's the pump that's gone, and if it's not totally necessary and just affects the emissions readings a bit I don't know if I should spend xxx $'s to get a new one.

    I'm not sure how much it affects emissions either, I just assumed that when emission testing time comes around in a year or so I'll just have the car warmed up to operating temperature and the cat converter should be doing it's job already and it won't matter as the readings should be low still.
    I could be way off on this, but that's why I'm asking.

    Thanks in advance for any advice on this!
  2. jonathanA4

    jonathanA4 New Member

    [ QUOTE ]
    we didnt get the secondary air injection system in the UK, not on Audi's anyway.

    [/ QUOTE ]

    Lucky you!

    Thanks for the info, I'm not really familiar with all the technicalities of how the system works, but I've got a general idea. I think I'm probably going to have to discuss the options further with my mechanic. I heard it's around $600-$700CDN to replace which seems like a lot for that part.

    As for failing the smog test, I thought the purpose of the pump was to get air into the system while the engine was warming up (since the fuel mixture is richer on startup? and the pump only runs for 30-60 seconds at startup and then shuts off?) and the induced air helps heat up the cat faster. So if the pump is just not functioning or bypassed, wouldn't the end result just be that the emissions are worse on startup only and it would take a bit longer for the system to heat up - but once it did heat up wouldn't it be functioning normally? /ubbthreads/images/graemlins/confused.gif
  3. excursion

    excursion Member

    Jonathan, iin that case you should be fine. I thought a smog test was performed when the car was cold as well as warm, but in hindsight it would be difficult to test cars when cold anyway.



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