A8 now misfiring on No.4 cylinder

[swidds]

Hi all ,

Well, I posted to the forum the other day about a misfire on cylinder 6 of my 2004 model Audi A8 3.7 Quattro.

Thanks to "Crusher" coming back to me with which cylinder No. 6 was, I was able to replace the coil pack and went back to smooth, trouble free motoring.

For 34 miles....

Now the engine is "throbbing" again, and cylinder 4 is misfiring...

I've bought another coil pack to solve this, but I've two questions -

1) What is the cylinder order starting from the back of the engine moving forwards (left to right, left to right, etc). Is it as straight forwards as 1, 2, 3, 4....? (I only know where 6 is for sure at the moment ).

2) Should I replace all the remaining coil packs to avoid any further issues? I'm concerned the new coil pack is making the older ones work harder, hence the almost immiediate failure of No.4.

It's going to be the thick end of 150 quid to do the rest, so I'd rather not if i don't have to and just put this quick failure down to "coincidence".

Cheers Guys!

[swidds]

Hi all,

fixed and running smoothly again (for the next 90,000 miles i hope ;-))

In case you need to know, the cylinder order on a 2004 model A8 3.7 quattro is...

Standing in front of the car facing the engine, the order up the left hand side of the engine, starting from the bumper end moving backwards towards windscreen

1,2,3,4

Then on the right hand side, again starting from the bumper moving backwards

5,6,7,8

Probably obvious to most of you and "schoolboy" stuff, but thought I'd post info anyway

[swidds]

..well , another 20 or so miles and its knackered again. I haven't even plugged the OBD computer in yet but I know it'll be another coil on another cylinder.

I'll annoyingly have to do all of them

Any ideas why this happens anyone?

[Gerbil]

I'll annoyingly have to do all of them

Any ideas why this happens anyone? [/QUOTE]

Did you get to the end of this?

My 2005 3.0 petrol failed in May with two coil packs. Limped to a dealer close to where I was and they replaced two coil packs. Asked if this meant they were all about to go, and was told this was very unlikely - just bad luck to have two go at once. Also very expensive to change all of them out (the two that were replaced were done under warranty)

Two weeks ago another coil went, and I limped to a different dealer (as I was half way up the M1!!) This dealer changed the one faulty coil and told me "if one has gone they will all go" best to change the other five, and it is not that expensive to do!!

As I had a meeting near the second dealer a week later I booked it in to get the remaining three changed (after explaining that two had already been done)

Just opened the bonnet to top up the washers and noticed I now have four very shiny new coil packs (I assume they are the bright red bits on each of the six cylinders?) but two old grubby looking ones.

Can any one tell me the cyclinder order on a 3.0 V6 (2005) as I thnk the second dealer may have changed the wrong coils!!

Help!!

[swidds]

Hi Gerbil,

Well, I bit the bullet so to say and changed all the remaining coils for new after my last post (sorry I didn't update folks!).

I'm pleased to say, that appears to have solved the problem after a few 1000 miles of trouble free motoring!.

What I think happens is the new coils are more effiecient than the older ones and put them under a greater strain.

This causes the "cascading" coil failures if you only replace them one by one.

I spoke to my local Audi specialist about this and he says he usually offers to change all the coils at the 70 thousand mile service/first cam belt service to avoid this envitable problem, athough people rarely take him up on it.

I seem to have slightly different new coil packs. Some are red, some are more orange and those have a different letter at the end of the part number.

Still work fine though, so it might be that your dealer has just changed yours with greasy hands Gerbil?

Hope this helps!

[Gerbil]

Hi Gerbil,


I seem to have slightly different new coil packs. Some are red, some are more orange and those have a different letter at the end of the part number.

Still work fine though, so it might be that your dealer has just changed yours with greasy hands Gerbil?

Hope this helps!

I went back to the dealer and asked them why I did not have 6 matching coils. And to confirm which ones had been changed this time around. The mechanic could not find out which coils had been replaced, but agreed to replace the two orange ones for matching red ones. Maybe I was being too fussy, but the oil on coil 3 looked like it had come from a leaking oil breather I had changed in November.......

If I still have the car at 140k I will get them changed again!!