Constant Misfire in Cylinder #3 after warm up
06-20-2018, 06:41 PM
#1
Constant Misfire in Cylinder #3 after warm up
So I started having constant misfire in cylinder #3 after car warms up. Starts up fine on cold start and after driving for few minutes, it starts misfiring. Check engine light and ESP light comes on sometimes. Generic misfire code.
Replaced pretty much everything I could think of. Bought new OEM spark plugs, swapped places spark plugs, swapped places coil packs, bought new coil pack, swapped places fuel injectors, cleaned fuel injectors. replaced ECU, replaced all of the engine harness wiring, cylinder pressure is good and leak down is good. Everything I tried is to no effect, same misfire in the same cylinder #3.
VCDS reports that cylinder 3 injector quantity is -1.49 mg/str while other injectors max out at 0.82 mg/str or much lower.
Checking misfire count in the software, only cylinder 3 is affected. Other cylinders always at 0 misfires.
Here is an interesting part, clearing the codes while the car is misfiring would sometimes stop the misfire for few minutes, and then starts misfiring gradually again. But this trick doesn't always work.
I am at loss of ideas as what can cause it, I was a point where I was asleep and I am dreaming of troubleshooting ideas.
Any help would be much appreciated.
Replaced pretty much everything I could think of. Bought new OEM spark plugs, swapped places spark plugs, swapped places coil packs, bought new coil pack, swapped places fuel injectors, cleaned fuel injectors. replaced ECU, replaced all of the engine harness wiring, cylinder pressure is good and leak down is good. Everything I tried is to no effect, same misfire in the same cylinder #3.
VCDS reports that cylinder 3 injector quantity is -1.49 mg/str while other injectors max out at 0.82 mg/str or much lower.
Checking misfire count in the software, only cylinder 3 is affected. Other cylinders always at 0 misfires.
Here is an interesting part, clearing the codes while the car is misfiring would sometimes stop the misfire for few minutes, and then starts misfiring gradually again. But this trick doesn't always work.
I am at loss of ideas as what can cause it, I was a point where I was asleep and I am dreaming of troubleshooting ideas.
Any help would be much appreciated.
07-21-2018, 03:41 AM
#7
AudiWorld Senior Member
Trending Topics
07-21-2018, 01:44 PM
#8
As for carbon build up, I actually cleaned the intake valves right before when I started getting the misfire. Unless I need to clean carbon somewhere else.
07-21-2018, 03:22 PM
#9
AudiWorld Member
Check the oil pressure. If there is not sufficient oil pressure to retard the camshaft setpoint you will get misfires. The fact that the engine is not throwing misfires when cold may indicate that it's the problem. Cold oil is thicker and oil pressure is always lot higher on cold engine. Once the oil warms up the viscosity increases and oil pressure drops.
Check for sludge buildup. Do you have any service history on the car? Who did oil changes, how frequently and most importantly was synthetic oil used? The 3.2 engine is not normally susceptible to sludging since it's naturally aspirated but if oil changes were neglected and if dino oil was used sludge will develop.
Check for sludge buildup. Do you have any service history on the car? Who did oil changes, how frequently and most importantly was synthetic oil used? The 3.2 engine is not normally susceptible to sludging since it's naturally aspirated but if oil changes were neglected and if dino oil was used sludge will develop.