[s-cars] I Fixed my misfire. Whoop-de-do!

[Doug Landaeta]

Glad to hear of your success!  You probably saved much more than a few
hundred pounds, - I figure the first repair would cost 400 pounds as they
replaced every coil, then told you you were good to go; when the misfire
still occurred, you'd come back and they would replace both POSs at another
400 pounds!.. Therefore actually fixing the problem, and that's if you're
lucky - of course this is solely based upon my experience with mechanics
here in the states.

Doug L
94 S4 (under the knife in NH) 

-----Original Message-----
From: Paul Heneghan [mailto:paul at heneghan.co.uk] 
Sent: Sunday, June 12, 2005 7:59 PM
To: s-car-list at audifans.com
Subject: [s-cars] I Fixed my misfire. Whoop-de-do!

I fixed my #2 misfire today.

With the help of some listers, the s-car-list archives, Scott Mockry's
wonderful site, and the Bentley manual, I'm now firing on all five cylinders
again.

As most people suggested, it was the POS.

On my S6 (UK spec), the arrangement of the POSs is slightly different to the
picture on Scott's site (early S4 perhaps?).  Mine are on a bracket with a
right angle in it, so they are perpendicular to each other.  Also, the right
hand one (as seen from the bumper) is the one that does #4 and #5.

I had a misfire on #2, so I swapped all the connectors on the POSs whereupon
the misfire moved to #5.  By the way, the leads to the input side of the
POSs weren't quite long enough, so I had to cut loads of tie wraps, and even
still, the leads were under quite a bit of strain.  The picture of the old
configuration on Scott's site makes it look as if it would be easier to swap
the connectors on that system.

Next, I swapped the POS's over, so that the POS with the failed channel only
had to handle two channels.  I had no heatsink compound, but I'll get some
during the week.  Then all I had to do was swap over the pins in the
connectors between #5 and the spare (#6).  Scott's site gave the location
and the colour codes of the wires.  The connectors come apart easily enough,
and you end up with the pink pin holder removed from the outer body of the
connector.  It's quite difficult to get the pins out though.  I made an
extraction tool to push back the barb on the inside while simultaneously I
pushed back the visible barb with a screwdriver.  My extraction tool was
made out of a 40mm length of 2mm diameter copper wire that I filed down
until it was a snug fit.  This worked on the first pin, but on the second
pin it didn't release the barb fully so I bent the barb back when pushing
the pin out - it seemed to survive being bent back in place.

Thanks to all concerned, I think I saved myself a bill of several hundred
pounds.

I can't believe the cost of these components - the coils and the POS should
cost a few tens of pounds (dollars).  Why do they cost hundreds?  It's
outrageous!

Paul