I've been having an off and on misfire issue for about 2 months now. It started doing it at higher RPMs and now it's starting to misfire at idle too. This morning it actually flashed the CEL light twice as I let it warm up.
I tried testing the ICM and coil and they seem to be fine. I've already tried replacing the spark plugs (NGK Laser Platinums), distributor rotor (OEM) and fuel filter (OEM). I haven't tried replacing the NGK spark plug wireset and OEM cap, but they were replaced on 1/5/2012. The old spark plugs and rotor were also replaced at the same time. I've done a dry compression test and checked the timing. The timing was at 15° and the dry compression results were:
__________________ 2001 Honda Prelude Type SH - 12/16/2011 to Present AEM BLOX Racing Enkei Racing Evolution Industries H&R ICB Motorsports KAIZENSPEED
K&N Ksport Megan Racing MFactory OBX Racing SICKSPEED Vibrant Performance VMS Racing
egr? either thing by the abs with the plugs or the thing on the im. the flange on my egr wouldn't hold a seal and was causing part of my misfire. it got much better after i put it in the trash and blocked it off.
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If you don't know what you want, you end up with a lot you don't.
All I can think of is Crank, cam, map, or ect as far as sensors go. Sounds like you have an intermittent electronic failure, but could be mechanical if timing belt somehow slipped a tooth. Have you tried adjusting timing via distributor to see if advancing or retarding decreases misfires?
I'm going to have to go through and test various sensors tomorrow. The misfiring seemed to have started when I began having to drive a little over 50 miles a day for work. I'm not sure if it's just a coincidence, but it could have something to do with it.
Last night I pulled the radio/clock fuse to reset the ECU and it seems to have helped reduce the occurrence of the misfire, but it's still there.
__________________ 2001 Honda Prelude Type SH - 12/16/2011 to Present AEM BLOX Racing Enkei Racing Evolution Industries H&R ICB Motorsports KAIZENSPEED
K&N Ksport Megan Racing MFactory OBX Racing SICKSPEED Vibrant Performance VMS Racing
I grabbed some info from the service manual and tested the TP (Throttle Position) sensor, MAP sensor and CYP (Cylinder Position) sensor and all were fine. I was going to test the IAT (Intake Air Temperature) sensor, but the first screw I tried to untighten got slightly stripped so I didn't want to make it worse. Considering the live data showed a reasonable temperature, I didn't see the point in ruining the only screws I had. The live data also showed a reasonable temperature for the engine coolant, so I don't think that's an issue either.
For some strange reason, after I cleared the CEL codes using my scanner, I test drove the car and it seems like the misfiring went away, at least for now. If it doesn't come back, I'll have to assume one of the connections were loose. I'll keep you guys updated if it does return. Thanks for the help.
__________________ 2001 Honda Prelude Type SH - 12/16/2011 to Present AEM BLOX Racing Enkei Racing Evolution Industries H&R ICB Motorsports KAIZENSPEED
K&N Ksport Megan Racing MFactory OBX Racing SICKSPEED Vibrant Performance VMS Racing
No, I didn't. How would you recommend checking the egr? I read a few threads and one talked about removing the plug from the egr and another talked about disconnecting the vacuum hose from the solenoid and blowing into it.
__________________ 2001 Honda Prelude Type SH - 12/16/2011 to Present AEM BLOX Racing Enkei Racing Evolution Industries H&R ICB Motorsports KAIZENSPEED
K&N Ksport Megan Racing MFactory OBX Racing SICKSPEED Vibrant Performance VMS Racing
i don't know how you'd check the ports on the im without drilling them out. the solenoid can be checked with a volt meter. the unit itself i was told to lift up and if it stalls its ok, but mine did that, but once i took the egr off and blocked its port it took away a lot of my problem. I still have the misfire (flashing at idle only now) but i think its due to a vacuum leak i caused looking for the misfire in the 1st place (somewhere on the im when i took it off to clean the carbon out). the original bad misfire is gone now that i took the egr off my car.
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If you don't know what you want, you end up with a lot you don't.
It was raining pretty hard today and I didn't have access to the garage. I did get a chance to unplug the electrical connectors for the EGR control solenoid valve and the EGR valve lift sensor to see if there was any change, but there wasn't.
I also recorded a video of the live data showing the voltages of the O2 sensors and the STFTs:
__________________ 2001 Honda Prelude Type SH - 12/16/2011 to Present AEM BLOX Racing Enkei Racing Evolution Industries H&R ICB Motorsports KAIZENSPEED
K&N Ksport Megan Racing MFactory OBX Racing SICKSPEED Vibrant Performance VMS Racing
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