03 Accord 2.4 Cyl 3 Misfire
12-02-2015, 04:10 PM
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03 Accord 2.4 Cyl 3 Misfire
2003 Accord coupe 2.4L automatic 228,000km original drive train. 6 months ago the car was misfiring on multiple cylinders. Replaced spark plugs with ones recommended by a local parts store and ignition coil on cylinder # 4 and the car ran ok until yesterday.
On the highway, car started misfiring hard couldn't get up to proper highway speed. Scanned it and had Cyl 3 misfire, Cyl 4 misfire, o2 sensor # 2, and random cylinder misfire codes. Replaced ignition coil on Cylinder # 3, cleared codes and went for a drive. Same condition as stated above, idles and runs fine but when the engine is under load (getting up to highway speeds) misfires. Scanned it again, Cylinder 3 misfire again. Removed the spark plug on Cyl 3 and there is some carbon on it but doesn't appear broken. Re-installed, cleared code and tried again but same issue.
Seems strange that there is no misfire present at idle or even if I rev the engine with the car in park. Only present under heavy engine load. Any tips on where to start? Thinking of replacing plugs with ones right from Honda and doing a compression test. Also if it helps car gets intermittent o2 codes but haven't got around to replacing the sensor yet.
On the highway, car started misfiring hard couldn't get up to proper highway speed. Scanned it and had Cyl 3 misfire, Cyl 4 misfire, o2 sensor # 2, and random cylinder misfire codes. Replaced ignition coil on Cylinder # 3, cleared codes and went for a drive. Same condition as stated above, idles and runs fine but when the engine is under load (getting up to highway speeds) misfires. Scanned it again, Cylinder 3 misfire again. Removed the spark plug on Cyl 3 and there is some carbon on it but doesn't appear broken. Re-installed, cleared code and tried again but same issue.
Seems strange that there is no misfire present at idle or even if I rev the engine with the car in park. Only present under heavy engine load. Any tips on where to start? Thinking of replacing plugs with ones right from Honda and doing a compression test. Also if it helps car gets intermittent o2 codes but haven't got around to replacing the sensor yet.
12-03-2015, 07:25 PM
#2
MM Gruppe B
Re: 03 Accord 2.4 Cyl 3 Misfire
Have the valves ever been adjusted?
https://honda-tech.com/acura-rsx-dc5...ments-2917144/
When the engine is cold, no or light load the engine may not misfire, but under load and heat with parts expanding the valve may be opening up just enough to lose compression, and thus a misfire.
But verify it is cylinder three first.
Mark your COPs #1-4 and then change them around to different cylinders.
Check that the spark plugs are properly torqued down.
If the misfire follows the coil then you can suspect that the coil is faulty.
If the misfire stays on the same cylinder, change the plugs around.
If the misfire follows the plug then you can suspect the plug is faulty, rare to have a bad plug, but it can happen.
If the misfire stays with the cylinder then suspect an issue with the cylinder.
Do a compression check with the cylinders, verify PSI.
If the valves have not been adjusted, or no record of them being adjusted within 160KM then I would suspect the valves are in need of adjustment.
https://honda-tech.com/acura-rsx-dc5...ments-2917144/
When the engine is cold, no or light load the engine may not misfire, but under load and heat with parts expanding the valve may be opening up just enough to lose compression, and thus a misfire.
But verify it is cylinder three first.
Mark your COPs #1-4 and then change them around to different cylinders.
Check that the spark plugs are properly torqued down.
If the misfire follows the coil then you can suspect that the coil is faulty.
If the misfire stays on the same cylinder, change the plugs around.
If the misfire follows the plug then you can suspect the plug is faulty, rare to have a bad plug, but it can happen.
If the misfire stays with the cylinder then suspect an issue with the cylinder.
Do a compression check with the cylinders, verify PSI.
If the valves have not been adjusted, or no record of them being adjusted within 160KM then I would suspect the valves are in need of adjustment.
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