What to do if your Mini is misfiring at idle?
What to do if your Mini is misfiring at idle?
Adjust both carbs two full turns toward rich, expecting it to run rich at idle, then take another acceleration run. If it then runs better at high speed, you may have the wrong needles in the carbs. Pull the needles and check the numbers on the shank. If the needles are the wrong number, install the correct needles. Reset the correct idle mixture.
What causes a cylinder to misfire at idle speed?
Ignition Misfires Photo 2: To prevent cylinder misfires at idle speed, some ignition systems fire each spark plug twice, producing a “double-strike” waveform. Intermittent ignition misfires can be caused by faulty spark plugs, spark plug wires, ignition coils and ignition coil drivers located in the ECM.
What causes a car to have a rough idle?
A rough or uneven idle can be an indicator of an engine that is misfiring. The air/fuel mixture is disrupted which can cause the engine to jump up and down. Illuminated check engine light Modern vehicles have many sensors that monitor the vehicle’s performance.
How to diagnose an intermittent engine misfire?
When diagnosing intermittent misfires, don’t forget to look at pending codes for indications of an individual cylinder misfire. If your scan tool’s misfire history indicates multiple cylinder misfires, focus on the cylinder with the most misfire counts.
Adjust both carbs two full turns toward rich, expecting it to run rich at idle, then take another acceleration run. If it then runs better at high speed, you may have the wrong needles in the carbs. Pull the needles and check the numbers on the shank. If the needles are the wrong number, install the correct needles. Reset the correct idle mixture.
Ignition Misfires Photo 2: To prevent cylinder misfires at idle speed, some ignition systems fire each spark plug twice, producing a “double-strike” waveform. Intermittent ignition misfires can be caused by faulty spark plugs, spark plug wires, ignition coils and ignition coil drivers located in the ECM.
When diagnosing intermittent misfires, don’t forget to look at pending codes for indications of an individual cylinder misfire. If your scan tool’s misfire history indicates multiple cylinder misfires, focus on the cylinder with the most misfire counts.
What does it mean when your SFT is high at idle?
Normal SFTs running about plus or minus 5%, or even as high as 10%, might not indicate a problem. But, for example, if the SFT is running high positive numbers at idle and returns to zero as the engine speeds up, you’re probably looking at a vacuum leak.
