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Old 02-18-2007, 01:28 AM   #1
benton0311
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2004 RSV 1000 R
Red/Silver

Default Misfire CEL (Enginuity)

For quite a while I've been getting misfire codes on all four cylinders due to injectors. I recently disabled the misfire DTCs with Enginuity. Now when the "misfire" situation occurs it will still throw a CEL but no codes will be stored. So the light is on but there are no codes at all.

Is there any way to keep the CEL from coming on when the situation occurs? Its a 2004 STi A2ZJ700J (AJ242) so there's no table to adjust misfire sensitivity with Enginuity or ECUFlash.
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Old 02-18-2007, 03:13 AM   #2
teiva-boy
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I'm going to ask a question, to your question

What in your injectors, causes a misfire code? And why would you want to disable this type of code, rather then fix the problem?

Back to your regularly scheduled topic...
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Old 02-18-2007, 09:47 AM   #3
Tea cups
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Some DTCs have different logic and disabling them using the traditional method doesn't always work. Best to figure out why your car is misfiring unless you already know (lightweight flywheel, UDP).
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Old 02-18-2007, 11:36 AM   #4
benton0311
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I've tracked the misfiring down to the perrin modified injectors. I know not all cars do it but there are a fair number of owners who have had misfire codes with some modded injectors. Not all cars and not all injectors. I tracked it down to them about a year ago.

I'm not asking about the source of the misfire code or what to do about it. I'm confident of the source and would rather disable the code and CEL than replace the injectors which run great except for a very slight stumble on cold starts. The reason this very slight stumble will trigger misfire codes is due to the sensitivity setting in the USDM ECU. On many of the 2.0 liter roms there is a table in enginuity adjust the sensitivity of misfire detection and it was found on the open source forums that foreign market roms (JDM, EDM, ADM, etc.) had a misfire detection value set much higher than the USDM roms from the factory.

The easiest solution to this problem would be to adjust the misfire detection threshold but that currenty is not an option for DBW roms, at least not with open source tuning. Basically I'm throwing a 1 count for each cylinder with a misfire sensitivity of 1, whereas with a setting of 10 count or more like the foreign market roms it wouldn't even register.

Last edited by benton0311; 02-18-2007 at 12:30 PM.
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Old 02-18-2007, 04:14 PM   #5
akira02rex
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I set my thresh hold to "5" and havn't seen them since.
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Old 02-26-2007, 02:28 AM   #6
LowUFO
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Akira, did you set it to five because four wasn't working for you or did you just raise it from one straight up to five and got lucky?

I ask because I tried four today and it didn't seem to work any better than having it at two.
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Old 02-27-2007, 01:43 PM   #7
Gethin
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Mine is set to 20, and with the UTEC L/C I get the CEL flashing sometimes to indicate misfire, but no stored codes or CEL light staying on.
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Old 02-27-2007, 06:09 PM   #8
LowUFO
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20?! Wow! Seems so high! Especially given that stock is 1, no?
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Old 02-27-2007, 07:06 PM   #9
Gethin
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Tried 5,10 and 15, and got the code stored with the CEL on. So 20 works for me
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Old 02-27-2007, 09:10 PM   #10
LowUFO
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Cool. I'm gonna keep raising mine and see what happens..
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Old 03-04-2007, 03:55 PM   #11
LowUFO
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Well, I made the suggestion to my engine builder/tuner and he doesn't want to just keep raising the threshold detection as he says he wants to find the actual cause of the problem. Especially since it didn't do this during the break-in period of my new hybrid. It started at the end of tuning.
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