12/10/2023 0 Comments 2000 mercedes kompressor coilsWe did not have the factory tool to analyze this problem, which means we were unable to watch the PCM counting which cylinder was misfiring at that moment in the timing. The worst case is when this happens and the PCM does not recognize the particular cylinder and ends up setting a random misfire when we really have a miss in only one particular cylinder. Some misfires do not happen long enough for the PCM to see the problem. You won’t be able to see the spark jumping to ground with this method because we are reducing the resistance to ground, making a direct connection with no air gap in between. On most vehicles, wetting the ignition components may help to locate misfires because the electrolytes provide an alternate path to the spark to a ground without high resistance. The engine was running without misfiring.ĭuring the moment that the misfire was not present, we sprayed a salt and water solution on the two suspected cylinders, #1 and #5, close enough in order to see the difference. The current drawn by each coil is twice that of a conventional coil because each double coil is energized by the PCM at the same time, but has two negative wires. That way, we are able to control the current at every individual coil using a low-amp probe and an oscilloscope. This fuse is designed to energize the six ignition coils. We removed the 15-amp fuse #58 from the driver’s-side Signal Acquisition & Actuation Module (SAM). But, when returning to idle speeds after cracking the throttle, we started to feel the misfire. No vibrations were felt when we raised the engine rpm while the vehicle was in Park and under no load. The long-term Fuel Trim Value was near 0% and the Loop Status was Open.Īfter 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. The freeze-frame data in Generic OBD II gave us the following PID values: PRM = 800, ECT = 190, Eng. Real-life repair scenario: 2003 E320, with 3.2L V6 engine and 120,000 miles.Ī customer brings his car into the shop with a “strange vibration.”Īfter we scanned the vehicle, we found the following DTCs: P0305, misfire on cylinder #5 and P0301, misfire on cylinder #1.
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