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So you can pretty much figure it something common to both banks, such as the solenoid valve, the vacuum hoses or the pump motor.
I pulled the belly pan, everything is at the right front corner just above the belly pan, found the small vacuum hose that goes to the combi valves, pulled on it from below and low and behold, it is not connected to anything up top!
Okay, so the plastic line broke at the 90 degree rubber fitting, I was thinking about ordering new parts, but I just took a piece of vacuum house out of my toolbox and cut a 4" piece and connected it to the part that goes to the solenoid (which I believe is on the front of the engine). I cleared the codes.....I'm pretty much 100% certain it's not coming back, but the jury is still out.
You can see where a piece of the plastic vacuum hose is still in the rubber 90 degree fitting, plus the fitting was cut. This "good" part in my hand is coming from the front of the engine, it takes a turn down at the right hand air box, hence the 90 degree fitting. The other hose that goes down to the combi valve was just hanging in the breeze.
I just checked how much a new plastic line that is about 24" long.....get this, $50 on audiusaparts! I would hate to find out what my local dealer would get for this....glad I just put a piece of vacuum hose in.
I washed my car, used Zmol HD cleanse and wax. It looks great! 86K miles on it now. Considering its probably worth 15K, I am thinking of just keeping it until something major breaks and then replacing it....which hopefully would be many years from now.
Nice looking car. The SAI system is finicky with no direct diagnostic sensors within it, which can make it tricky to diagnose.
From my meddling/fixing it on mine, a hand vacuum pump is an essential tool in diagnosing it.
I see your thread on the issue you had, appears you have a A8 with a 4.2. I was looking for the combi vales on the back of the motor, but found in the Bently that for the S8 they are both at the SAI pump location at the front bottom of the car, just above the belly pan. So everything is right there vs. being on the back of the engine. Super easy to get to and troubleshoot. Lucky for me it took all of 30 seconds to figure it out. Who would of thought the S8 would be easier?
The part on my car that was bad was part 25 where it has the 90 degree fitting at the top. You can see it then goes over to the front of the motor for the solenoid valve. On the D2 40 valve motors, the vacuum hose would shrink over time and then literally pull off the solenoid valve causing the system not to work in the same manner mine did.
Easiest way to connect the sai hose to the combi value?
The second hose of the sai pump (not the one goibg directly to the bottom of the air box, but the second one that the diagram says connects to the combi values behind the engine. Mine has just been dangling and I can't see an easy way to find where it reconnects. Help, pics plz!
10-07-2018, 03:01 PM
Think I fixed my Secondary Air Injection Issue
