It seems like I'm posting almost daily about a new problem so here goes. My check engine light came on soon after I had my sparkplugs and coil packs replaced. I didn't think much of it since the car was and is still running fine. I was curious as to what the problem was this time so I used an OBD-II scanner to get the code the engine was throwing. It came up as P0357, Ignition Coil G Primary/Secondary Circuit. What I don't know is what cylinder is #7. What I was planning to do is to swap the coil pack to another cylinder and see if that coil pack is the problem. Thank you again for your help.

 

When you're facing the motor from the front of the car

4 8
3 7
2 6
1 5



^C6/A6 4.2 motor, just using the image for the visual-aid

 

Thanks, that's just what I was looking for. In addition to the ignition coil problem, I also have a problem on start up. When I start the engine when it's cold, it revs up to about 1200-1500 rpm before settling at 1000 rpm for warm up. What I experience is that periodically the engine will drop down to about 200 rpm after the 1200-1500 rpm rev and then it revs up stronger than it did on start up. Also, twice now it has just died immediately following the 1200-1500 rpm rev. Accompanying the weird revving is a loud whining sound. Do you know what could be causing the problem? I'll see if I can get a video of it uploaded later on tomorrow.

 

U -
I have the same cold start situation with the same high pitched whining sound. What is that thing that makes all the noise? I tried unplugging it and it didn't make any difference with how the car ran, but I did get a CEL. Since I don't own a scanner, I don't know what the code is. Any ideas? The unit making the noise is on top of the engine toward the driver side near the fire wall. My car is a 2001 A6 2.7T.
Scott

 

I have no idea what is causing that to happen. My best guess for the start up condition is that the fuel filter is clogged up or the fuel pump is failing but that wouldn't explain the whining sound. Maybe it's something with the ecu since mine has been throwing off random codes. I'll try to get a video of the start up tomorrow morning.

 

If you don't own a scanner, what I do is go to the local auto parts store which in my case is O'Reilly's and they let you borrow theirs free of charge.

 

What you're hearing is the secondary air injection pump for warming up the cats. It only runs for a short while on cold startup - it just gets the catalytic converters working faster. It throws a CEL if it's not working because it's an emissions device. You can remove it, but it's not trivial - search the forums for secondary air injection delete - but it will continue to throw a CEL until you get the ECU flashed to remove the check to see if it's working.
Jim

 

Here is the video I made

 

That sound does not sound too bad yet. I'm pretty sure it is the SAI (Secondary air pump). Once this sounds gets louder and more annoying you can look into getting it replaced or if you feel it is already too annoying, do it now. However it really is not doing much for your - it's purely for emissions (see eejimm's post). Replacement however runs into the hundred's for OEM so personally I would leave it until it completely dies or remove it and do the SAI delete.

 

What about the surge and almost stall at start up?