Mechanics

MISFIRE

Audi A6

I have a misfire on my Audi A6 2.7t Quattro. It started on Cyl #3 and 4. I put in some fuel injector cleaner and replaced the plugs and Cyl #3 misfire went away. I replaced the coils on Cyl #3 and #4 but it still misfires. This is a very strange misfire. It misfires at idle, off idle and under load but seems to go away at 2000 rpm with no load and 2800 with load. This all started on the same day. Could it be fuel
injectors?
Avatar
14forest
September 16, 2007.



There is a lot you are not telling us...What condirion were the plugs you removed? I'm thinking you need to do a compression test I don't see the year on this post. That said here are some testing tips,


http://www.2carpros.com/forum/automotive_pictures/62217_Misfires1_copy_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_Misfires2_copy_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_Misfires_copy_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_30961_mitchell_2_26.jpg


Merlin2021
Sep 16, 2007.
The car is a 2000. I just had the timing chain replaced, cam seals and valve cover gaskets. The mechanic checked the whole car including compression. Everything was in spec. Spark plug # 4 was fouled before I replaced it. Spark plug #3 was OK.
Half the tests you sent me don't apply as I already replaced the coils and plugs.

Tiny
14forest
Sep 18, 2007.
Ok so the coils have been replaced, what about the plug jackets? If compression is good, these cylinders are on oppsite banks and both at the front position, are we sure the camshaft sensor is set correctly? P.S. Just tryin to help, I am not an Audi specialist! But I did spend quite a bit of time researching for you, if you need more reseach call me! Let me know how things go. Good luck. I do like a nice ride myself.

Merlin2021
Sep 18, 2007.
I'm replacing injector #4 tonight.

Tiny
14forest
Sep 19, 2007.
I replaced the injector. Still same codes. I then swapped ignition modules. Codes went from Cylinder #4 to cylinder #1. I bought a new ignition module and all the codes are now gone. Car runs great. For all you volkswagon and Audi people out there go to virtualvillage. Com and look at their Scanmax VAG reader #405. It is a life saver for $149. I bought one.

Tiny
14forest
Sep 28, 2007.