3.2 #3 Misfires

Euro Tech colorado · 06-02-2009, 08:22 AM

I have been working on a 2005 A6 3.2 with intermittant #3 misfires. It usually happens after the car is warmed up and after
revving engine in the higher rpm's. The engine light flashes and stumbles but shutting the engine off and back on will usually reset the problem. The coils have been swapped then replaced. The spark plugs have been swapped then replaced. This car came in with 7 dtc's in the ECM and we've fixed them all except this intermittant misfires. The low pressure fuel pump is new. Any ideas why #3 keeps misfiring?

extetty · 04-07-2011, 05:27 PM

Ok, heres my game plan. Please tell me if Im way off on this but I think this could be a good way to go about skewing....

Ohm each injector. Find the average. Thats the mean. From that number I can increase or decrease individual injector skews so that they all match.

Back to the mis-fires...I noticed when I was checking the plugs/cables that the plastic tubing that goes over the spark plug wires to protect them from heat or EMI, I think had moved down to the coil for cylinder #4. The alternator ground runs in parallel to the spark wires and was touching the spark wire for #4 where the plastic tubing was not. I moved the plastic tubing back up so that the ground is touching the plastic and not the wire. Also, when I put plugs 4 & 6 back in, I gave them an extra turn just for good measure. I made certain that the wires were on really good and pushed down on the coils to make sure they were connecting.

Tonight, I ran out to the store and didnt see the misfires. Two at start up on different cylinders, but none on # 4. Once warmed up, nothing. Put in park, nothing. Drive, nothing. Acceleration was a lot smoother. I dont know what it was but it seems like its fixed. Going to keep an eye on it, but for certain, I want to ohm out the injectors anyway.

aaa123 · 08-04-2011, 11:24 PM

I have a 2007 A4 3.2 that has a misfire problem. When I start the car cold it shakes. Then if I try to drive it, it will hesitate. It is under warranty. It is in the shop for the third time. It required the next level technician from Audi to diagnose the problem. If you know something about misfires I would greatly appreciate some information. I am concerned that I am doomed with this problem.

Thanks

aaa123

aaa123 · 08-04-2011, 11:29 PM

I have a 2007 A4 3.2 that has a misfire problem. When I start the car cold it shakes. Then if I try to drive it, it will hesitate. It is under warranty. It is in the shop for the third time. It required the next level technician from Audi to diagnose the problem. Audi said that there is a problem with the fuel injector. If you know something about problems with fuel injectors/misfires I would greatly appreciate some information. I am concerned that I am doomed with this problem.

Thanks

aaa123

aaa123 · 08-04-2011, 11:31 PM

I have a 2007 A4 3.2 that has a misfire problem. When I start the car cold it shakes. Then if I try to drive it, it will hesitate. It is under warranty. It is in the shop for the third time. It required the next level technician from Audi to diagnose the problem. Audi has said it is a problem with the fuel injector. If you know something about fuel injectors/misfires, I would greatly appreciate some information. I am concerned that I am doomed with this problem.

Thanks

aaa123

audi01a6 · 08-05-2011, 03:22 AM

most of the time its a carbon built up,what i have done is removed intake
and cked valves,or if u have a good borescope remove spark plugs and ck
all the valves,common problem with the 3.2 engine is carbon builtup,
just do a decarbon,make sure customer uses good high octane gas,
and i hope that helps

DAN B.

04-07-2011, 05:27 PM	#2
extetty Audiworld Junior Member Garage is empty, add now Join Date: Jan 2011 Location: Northern Ireland Posts: 23	3 2 #3 Misfires Ok, heres my game plan. Please tell me if Im way off on this but I think this could be a good way to go about skewing.... Ohm each injector. Find the average. Thats the mean. From that number I can increase or decrease individual injector skews so that they all match. Back to the mis-fires...I noticed when I was checking the plugs/cables that the plastic tubing that goes over the spark plug wires to protect them from heat or EMI, I think had moved down to the coil for cylinder #4. The alternator ground runs in parallel to the spark wires and was touching the spark wire for #4 where the plastic tubing was not. I moved the plastic tubing back up so that the ground is touching the plastic and not the wire. Also, when I put plugs 4 & 6 back in, I gave them an extra turn just for good measure. I made certain that the wires were on really good and pushed down on the coils to make sure they were connecting. Tonight, I ran out to the store and didnt see the misfires. Two at start up on different cylinders, but none on # 4. Once warmed up, nothing. Put in park, nothing. Drive, nothing. Acceleration was a lot smoother. I dont know what it was but it seems like its fixed. Going to keep an eye on it, but for certain, I want to ohm out the injectors anyway.

08-04-2011, 11:31 PM	#5
aaa123 AudiWorld Newcomer Garage is empty, add now Join Date: Aug 2011 Posts: 3	Fuel Injector /Misfires 2007 A4 3.2 I have a 2007 A4 3.2 that has a misfire problem. When I start the car cold it shakes. Then if I try to drive it, it will hesitate. It is under warranty. It is in the shop for the third time. It required the next level technician from Audi to diagnose the problem. Audi has said it is a problem with the fuel injector. If you know something about fuel injectors/misfires, I would greatly appreciate some information. I am concerned that I am doomed with this problem. Thanks aaa123

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08-04-2011, 11:24 PM	#3
aaa123 AudiWorld Newcomer Garage is empty, add now Join Date: Aug 2011 Posts: 3	I have a 2007 A4 3.2 that has a misfire problem. When I start the car cold it shakes. Then if I try to drive it, it will hesitate. It is under warranty. It is in the shop for the third time. It required the next level technician from Audi to diagnose the problem. If you know something about misfires I would greatly appreciate some information. I am concerned that I am doomed with this problem. Thanks aaa123

08-04-2011, 11:29 PM	#4
aaa123 AudiWorld Newcomer Garage is empty, add now Join Date: Aug 2011 Posts: 3	I have a 2007 A4 3.2 that has a misfire problem. When I start the car cold it shakes. Then if I try to drive it, it will hesitate. It is under warranty. It is in the shop for the third time. It required the next level technician from Audi to diagnose the problem. Audi said that there is a problem with the fuel injector. If you know something about problems with fuel injectors/misfires I would greatly appreciate some information. I am concerned that I am doomed with this problem. Thanks aaa123

08-05-2011, 03:22 AM	#6
audi01a6 AudiWorld Senior Member Garage is empty, add now Join Date: Oct 2005 Location: sunny florida Posts: 644	most of the time its a carbon built up,what i have done is removed intake and cked valves,or if u have a good borescope remove spark plugs and ck all the valves,common problem with the 3.2 engine is carbon builtup, just do a decarbon,make sure customer uses good high octane gas, and i hope that helps DAN B.