Hey guys i being working on a 2004 volkswagen passat came in with several codes p0411 p0171 p0300 and p0302 all of those codes are gone except the p0302. The problem is that the misfire only happens for around 5 to 10 seconds in the morning and then its good all day spark plug was swap same with coil and injector
I’d first verify with boroscope (after cold-soak) that no coolant was entering combustion chamber. I then would analyze the ignition waveform (obtained from a high-tension cable between COP and sparkplug) and monitor for activity. I’m not intimately familiar with this vehicle so I don’t know if it is of a GDI fueling strategy but certainly possible that carbon may be the culprit .
Since the problem only happens once per warm up cycle, start your problem analysis with a relative compression test. Use an ignition sync from the #1 ignition coil trigger, and give it about a 20 second crank. This will rule out any valves sticking. When you were swapping spark plugs, did you do it before the engine was started and was there any color difference between any of the plugs? On
Agree with Brandon and Albin I'm old-school simple so what I'd do first is to motor the starter for about 10 seconds after its sat overnight, without allowing the engine to start and yank the plug. If it's is wet, you've found the likely problem.
There is a software update for cold misfires. Refer to TSB 01-09-09.
Can you take a look at the intake valves for carbon build up, Have you monitor the mass airflow and is it a factory original sensor? Not getting unmerited air from any elbow rubber fitting hoses under the manifold with a crack fracture what is live data measuring block values on group 14&15 misfires is rear main seal leaking?
When i swap the inyectors i look inside and the valves look clean also i smoke the engine to look for leaks nothig found
when you smoke intake you have to put about 5 psi regulated pressure to find small leaks otherwise they will never show, can you post some scan data of mass airflow
I'll have to agree with a possible coolant leak during a cold start. You should be able to get it hot and let it cool off and check that cylinder for coolant before you start it. I've seen the intake ports crack numerous times on these. It's not a GDI, so those common issues are thrown out. It's preferred to check fuel trim with a scan tool that can check the measuring block data, because the