Why does my Mercedes Benz misfire at idle?
The long-term Fuel Trim Value was near 0% and the Loop Status was Open. After turning on the engine, we observed while the engine was at idle that the misfire or “strange vibration” as described by the customer was barely noticeable. No vibrations were felt when we raised the engine rpm while the vehicle was in Park and under no load.
What kind of misfire is a 2003 Mercedes-Benz?
The diagnosis begins with these findings: DTC P0305, misfire on cylinder #5; and DTC P0301, misfire on cylinder #1. Real-life repair scenario: 2003 E320, with 3.2L V6 engine and 120,000 miles.
How to troubleshoot ignition problems on a Mercury outboard?
Many ignition problems stem from electrical issues, but there are a few general troubleshooting tasks you should perform. Check that there is plenty of gas in the gas tank and that all fluid levels are at the right level. Make sure that all wires are connected properly. If there is no start from the engine, there may be no spark present.
What causes hard starting and rough idle on a Mercury?
Faulty Air Temperature Sensor: Will cause hard starting and rough idle. Air temp sensor should be checked with an Ohm Meter with a Cold Start Ignition Test. *ACU and PCU only. Incorrect fuel pressure: Can be caused by a bad fuel pressure regulator, or restricted return. On Laser EFI motors, look under the Fuel Pressure Regulator.
What happens when a Mercedes engine misfire occurs?
As soon as an engine misfire occurs on a Mercedes-Benz, you will notice poor engine performance and strange vibrations that in some cases can be felt even in the driver cabin. The first thing that comes to mind when you get an engine misfire is: “This is going to be expensive.” Take a deep breath because in most cases it doesn’t have to be.
Can a loose spark plug cause an engine misfire?
Check your vehicle repair manual for more information about the recommended spark plug for your engine. When installing new spark plugs tighten them to the torque listed in your repair or service manual. Leaving a spark plug loose (under-torquing) will lead to overheating, pre-ignition, or misfires.
When to ignore a trouble code for a misfire?
When retrieving trouble codes, only consider related codes to a specific misfire problem, like an ignition coil failure code. If a trouble code is present and doesn’t pertain to the immediate problem like an EVAP code, ignore it until a later time, when the engine is running properly these codes could cycle out.
How can I find out if my engine is misfired?
Some car computers detect misfires by measuring electrical activity [ionization] at the spark plug electrodes. You can retrieve stored Diagnostic Trouble Codes with a code reader (for OBD I systems on pre-1996 vehicle models) or a generic scan tool (for OBD II systems-1996 or newer models; some scan tools can read both OBD I and II).