Mysterious CEL Blinking
#21
My tsx had the exact same problem where it would flash and go away, but it would bog like crazy and you could hear and feel the misfiring with the loss of power. Mine was a simple failure of 2 coil packs. The other two failed the following week and there was never a problem since replacement. It's bulshit how they all failed almost exactly at the the same time. Bullshit quality if you ask me. Car only had about 80k at the time.
#22
Former Moderator
Originally Posted by Kirpich' date='Jan 7 2009, 08:59 PM
So that cylinder's fuel mix will be bad, and cause a misfire. The knock sensor picks it up, and flashes the CEL at you to let you know that the conditions inside the cylinder could be detrimental to its health.
The CKP sensor is used for Misfire detection.
#23
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Thread Starter
thanks for the additional feedback.
I had at least 3/4 tank of fuel when this happened.
Also, when this was happening, my engine was running great. sounded fine. I punched the throttle and it accelerated like a champ. I hit vtec and all was well.
I had at least 3/4 tank of fuel when this happened.
Also, when this was happening, my engine was running great. sounded fine. I punched the throttle and it accelerated like a champ. I hit vtec and all was well.
#24
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Just for fun I googled "misfire" and found this:
TRACKING MISFIRES
No engine fires every cylinder 100 percent of the time. Misfires can occur at idle, when the engine is pulling hard under load, at high rpm and during throttle transitions as the air/fuel mixture changes. A few misfires are to be expected under these conditions and should cause no major performance problems or significant increase in emissions. But if the misfires get out of hand and occur too often, they can make the engine idle or run rough, stumble when accelerating, waste gas and fail an emissions test.
On 1996 and newer vehicles that are Onboard Diagnostics II (OBD II) compliant and have misfire detection, the OBD II system tracks and counts misfires. The misfire monitor runs continuously on vehicles that have it anytime the engine is running. On most applications, the OBD II system uses the crankshaft position sensor (CKP) to look for subtle changes in the speed of the crankshaft between cylinder firings. If the crank suddenly slows a bit, it indicates a misfire. The only problem with this approach to detecting misfires is that the misfire monitor can sometimes be fooled when the vehicle is driven on a rough road. Consequently, some OBD II systems are programmed to temporarily ignore variations in crank speed under rough-road conditions.
On some vehicles, the amperage of the spark current is analyzed when each spark plug fires to determine if the mixture burned or not.
When the OBD II system detects a misfire, it stores operating data such as engine speed, load and warm-up status. While the misfire is happening, the OBD II system is supposed to flash the MIL lamp once a second to alert the driver. Because this might distract the driver from her cell phone conversation, sipping her Starbucks coffee or yelling at her kids in the back seat, the OBD II system will set a temporary misfire code after the second such occurrence. From that point on, the MIL lamp should flash every time the misfire returns. If the same thing happens on the next trip, the MIL lamp should blink as before and remain on even when the misfire ceases.
If the misfire problem has gone away and does not recur on the second or following trips, the OBD II system may erase the temporary misfire code and forget the entire episode. The code may also be erased if no misfires are encountered under similar driving conditions during the next 40 drive cycles.
Knowing this, you should always look at the history freeze-frame data when diagnosing a misfire code. If the code was set when the engine was cold, chances are the OBD II system is being overly sensitive and there is no real misfire problem. Check for any technical service bulletins (TSBs) that may be out on the vehicle for false misfire codes. The cure, in many instances, is to flash reprogram the PCM so the OBD II system will be less sensitive to misfires.
No engine fires every cylinder 100 percent of the time. Misfires can occur at idle, when the engine is pulling hard under load, at high rpm and during throttle transitions as the air/fuel mixture changes. A few misfires are to be expected under these conditions and should cause no major performance problems or significant increase in emissions. But if the misfires get out of hand and occur too often, they can make the engine idle or run rough, stumble when accelerating, waste gas and fail an emissions test.
On 1996 and newer vehicles that are Onboard Diagnostics II (OBD II) compliant and have misfire detection, the OBD II system tracks and counts misfires. The misfire monitor runs continuously on vehicles that have it anytime the engine is running. On most applications, the OBD II system uses the crankshaft position sensor (CKP) to look for subtle changes in the speed of the crankshaft between cylinder firings. If the crank suddenly slows a bit, it indicates a misfire. The only problem with this approach to detecting misfires is that the misfire monitor can sometimes be fooled when the vehicle is driven on a rough road. Consequently, some OBD II systems are programmed to temporarily ignore variations in crank speed under rough-road conditions.
On some vehicles, the amperage of the spark current is analyzed when each spark plug fires to determine if the mixture burned or not.
When the OBD II system detects a misfire, it stores operating data such as engine speed, load and warm-up status. While the misfire is happening, the OBD II system is supposed to flash the MIL lamp once a second to alert the driver. Because this might distract the driver from her cell phone conversation, sipping her Starbucks coffee or yelling at her kids in the back seat, the OBD II system will set a temporary misfire code after the second such occurrence. From that point on, the MIL lamp should flash every time the misfire returns. If the same thing happens on the next trip, the MIL lamp should blink as before and remain on even when the misfire ceases.
If the misfire problem has gone away and does not recur on the second or following trips, the OBD II system may erase the temporary misfire code and forget the entire episode. The code may also be erased if no misfires are encountered under similar driving conditions during the next 40 drive cycles.
Knowing this, you should always look at the history freeze-frame data when diagnosing a misfire code. If the code was set when the engine was cold, chances are the OBD II system is being overly sensitive and there is no real misfire problem. Check for any technical service bulletins (TSBs) that may be out on the vehicle for false misfire codes. The cure, in many instances, is to flash reprogram the PCM so the OBD II system will be less sensitive to misfires.
#27
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Slow: by putting both methods of misfire detections in bold I was not questioning what you said about the Sk2 using the CKP
What is a 94-04 Honda 3.5 RL anyway?
jyeung528 Posted on Jan 10 2009, 09:45 AM
I don't think so, but as long as it never returns I guess you're allright.
What is a 94-04 Honda 3.5 RL anyway?
jyeung528 Posted on Jan 10 2009, 09:45 AM
so i suppose it's "normal" to have a misfire under conditions such as going uphill.
I don't think so, but as long as it never returns I guess you're allright.
#29
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My money is on faulty fuel injectors.
Not that the vehicles compare or anything, but I had the exact same thing happen to my Chevy Suburban, reproducible every time on an uphill climb under heavy / wide open throttle. The fuel injectors had to be replaced in the Chevy and problem vanished.
Not that the vehicles compare or anything, but I had the exact same thing happen to my Chevy Suburban, reproducible every time on an uphill climb under heavy / wide open throttle. The fuel injectors had to be replaced in the Chevy and problem vanished.
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