Still can't figure this cyl 6 misfire shiet out but getting closer, interesting developments...
02-19-2009, 05:38 PM
#1
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Still can't figure this cyl 6 misfire shiet out but getting closer, interesting developments...
<center><img src="http://pictureposter.audiworld.com/48795/coil.jpg"></center><p>
stock 01 S4, tip, 102k - not beaten on.
(also the coil pictured is a good coil, mine actually bulges out a good 1/8 inch and is cracked and melted at the bulge)
Issue: Steady Misfire on cylinder 6 only- and seriously i'll paypal someone $20 for the right fix!!
In chrono order:
CODES: misfire cyl 6 + random cyl misfire, VAG shows misses only occuring on cyl 6.
(all done within the last week)
-Replaced cyl 6 coil (side melted, arcing to valve cover - no luck.
-replaced all 6 coils and coil to plug connectors, and all 6 plugs (ngk prf6q plugs) - no luck
-swapped the POS (amp/icm, etc on top of the airbox)
-unplugged the MAF
-observed O2 function, EGT values and ECT values thru vag.
-looked at all the ignition coil connectors (pulled back connector boot)
-swapped out cyl 4 fuel injector with cyl 6 injector. no luck
-removed the ecu cover and inspected ECU and pins
-inspected wiring for the injectors and coils for bank 2 (cyl 4,5,6)
-2nd new cyl 6 coil now melted/ arcing like the first.
-put in another plug that is also a PFR6Q NGK that I know fired well from a different 2.7t. Misfire stayed with cyl 6.
-put in a bosch plug. misfire stayed with cyl 6.
-sprayed carbon cleaner to the top of cylinder 6 to clean it up some (some carbon build up on top of piston).
-In an effort to insulate the coil where it arcs out, I wrapped the coil 3 times at the top with electrical tape, also took that new PFR6Q plug and shrunk the gap down to .28
-Put in a 20oz bottle of Techron on a Shell premium fill up today.
--- Drove the car and everything was relatively smooth (but only after the spark plug gap decrease to .28 and the electrical tape around the coil) EXCEPT misfire in cyl 6 at WOT, but you really need to be on it. After a few WOT pulls the misfire is more pronounced at lower throttles but not misfiring every rev.
my plan:
- compression test
- pressure test
- re gap all plugs to .28 or .25 (just for observations)
- test cyl 6 coil connector wires per bentley
- switch plugs altogether to something different? maybe a lower resistance copper plug to see any difference.
ANY thoughts whatsoever on additional ideas?? Any way I can tell what the environment is like within the cylinder at higher throttle? Any logs anyone would like me to post to have interpreted? I have scoured AW searching and reading for a good 6-8 hours about various topics and have actually emailed 2 people that continue to have misfires in cyl 6 to this day...
Any help TIA!
stock 01 S4, tip, 102k - not beaten on.
(also the coil pictured is a good coil, mine actually bulges out a good 1/8 inch and is cracked and melted at the bulge)
Issue: Steady Misfire on cylinder 6 only- and seriously i'll paypal someone $20 for the right fix!!
In chrono order:
CODES: misfire cyl 6 + random cyl misfire, VAG shows misses only occuring on cyl 6.
(all done within the last week)
-Replaced cyl 6 coil (side melted, arcing to valve cover - no luck.
-replaced all 6 coils and coil to plug connectors, and all 6 plugs (ngk prf6q plugs) - no luck
-swapped the POS (amp/icm, etc on top of the airbox)
-unplugged the MAF
-observed O2 function, EGT values and ECT values thru vag.
-looked at all the ignition coil connectors (pulled back connector boot)
-swapped out cyl 4 fuel injector with cyl 6 injector. no luck
-removed the ecu cover and inspected ECU and pins
-inspected wiring for the injectors and coils for bank 2 (cyl 4,5,6)
-2nd new cyl 6 coil now melted/ arcing like the first.
-put in another plug that is also a PFR6Q NGK that I know fired well from a different 2.7t. Misfire stayed with cyl 6.
-put in a bosch plug. misfire stayed with cyl 6.
-sprayed carbon cleaner to the top of cylinder 6 to clean it up some (some carbon build up on top of piston).
-In an effort to insulate the coil where it arcs out, I wrapped the coil 3 times at the top with electrical tape, also took that new PFR6Q plug and shrunk the gap down to .28
-Put in a 20oz bottle of Techron on a Shell premium fill up today.
--- Drove the car and everything was relatively smooth (but only after the spark plug gap decrease to .28 and the electrical tape around the coil) EXCEPT misfire in cyl 6 at WOT, but you really need to be on it. After a few WOT pulls the misfire is more pronounced at lower throttles but not misfiring every rev.
my plan:
- compression test
- pressure test
- re gap all plugs to .28 or .25 (just for observations)
- test cyl 6 coil connector wires per bentley
- switch plugs altogether to something different? maybe a lower resistance copper plug to see any difference.
ANY thoughts whatsoever on additional ideas?? Any way I can tell what the environment is like within the cylinder at higher throttle? Any logs anyone would like me to post to have interpreted? I have scoured AW searching and reading for a good 6-8 hours about various topics and have actually emailed 2 people that continue to have misfires in cyl 6 to this day...
Any help TIA!
02-19-2009, 05:47 PM
#2
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Maybe try swapping the ignitors on top of the airbox around...
to see if the miss moves to the other bank. I'm not sure the ignitors can only affect 1 cylinder but it's worth a try. good luck!
02-19-2009, 06:25 PM
#6
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So i'm wondering if anyone with wiring diagram skillz can help with this:
<center><img src="http://pictureposter.audiworld.com/48795/icm_checking.jpg"></center><p>wondering if i'm looking for a bad ground where i should look if i'm shorting consistently at my #6 coil...
02-19-2009, 06:53 PM
#7
Coilpacks 4 and 5....
....ground through coilpack 6, via pin 4A.
I would jump another ground from coilpack 5, pin 4A to ground. If ground connection 12 has a weak connection, it may ground all three through coilpack 6. You could also try cleaning up ground connection 12.
I would jump another ground from coilpack 5, pin 4A to ground. If ground connection 12 has a weak connection, it may ground all three through coilpack 6. You could also try cleaning up ground connection 12.
