RomRaider

In checking for some missing CEL disable defs for 16-bit ECUs reported by a user (P2096, P2097), I noticed that the tool I developed to generate CEL defs was also ignoring the P0301, P0302, P0303, P0304 CELs due to the number of drive cycles they are set to. I'll be adding these to next ECU def update. If anyone who has persistent misfire CELs and would like to test the new defs, PM me your rom.

As a side note, P0171, P0172 will also be added to the next ecu def update.

Don't forget that missfire CEL is usually generated by a faulty neutral position switch (on top of the gera box for STi, on side of the gearbox for WRX). This CEL is a good indicator of when to change this switch.
Anyway logging this switch will tell you wether it is faulty or not

what??

a faulty neutral position switch will generate misfire CEL on all WRX

That may be the case, but this test is for those with false misfires due to aftermarket flywheel, crank pulley, etc.

This is alittle off-topic. But I am still getting a phantom misfire code on 04 STI, 32-bit. I did mention this in the BUG REPORTING. Merchgod, mentioned a hard reset. I did that, but it still turns on the CEL. I have not tried the test release w/ the 'Reset ECU' option.
Absubtle
CO

Before you said you were getting no code but it was showing up in freeze frame data and still get the CEL? Is that still the case? Freeze frame data doesn't show a code (does it?), so how do you know what code is being set (or does it appear in pending)?

Check engine light comes on. I scan the code and there is no information found. In freeze frame data, I see a cylinder 4 misfire code.
The cold start and idle, on the car is alittle rough, and that is usually when it kicks on. It's not a big deal to me, it justs makes me curious why I can't completely disable it. So far, it's only been cylinder 4.
Thanks again.
Absubtle
CO

Don't know. Have you determined it to be false misfire? It must be severe as I haven't heard of anyone else with this problem with the 32-bit ECU and the CEL disabled.

i have a misfire code cylinder 4 about a month ago on my 05 sti.
when is cold started fine and warm up the code will lit.
after doing a compression test the 4 cylinder was indeed lower then the rest.
So took out the cylinder head goooossssssshhh nothing
there are lots of carbon deposits and the valves are not seating in postion.
but i change a new engine instead of overhauling.

I think if the code comes on, should try to use some cleaner instead of just stripping off like what i have done.

2002 WRX

my misfires were caused by vac leaks on the intake (pcv/evap emissions lines right before it runs under the manifold). i have since capped them off without any further problems.

Just to update this thread, I've already added the missing CEL codes to the last ECU def update.

Bill,
I tuned an 02 WRX last weekend. It has a 2.5L, forged pistons, TGV deletes, FP green, Big MAF, and BC 280 cams. It DOES misfire at idle. A lot. And its because of the cams. I had turned the idle up to 1200, set the misfire threshold at 200, and sent him on his way.

Got a call back, the CEL came on. Came up with P0301, 302, and 304. So I thought no big deal, turned off 301, 302, 303, 304, and sent him on his way again. Got a call an hour later saying the same thing, CEL came back on. He said he put it on a code scanner and no CELs were found, but the light was on.

Any ideas?

Its the old rev 02 rom.... A4SGA00C

Only thing I was thinking was to maybe change it to A4TC400L ???

misfire CELs are handled differently than the other CELs. I'm not sure how to overcome this. Did you try setting the misfire count to maximum (255)?

No, I didnt. He had already headed home when the second incident occurred, and I was off doing something else. But ike I said, it was already set at 200, would 255 disable it altogether or is it still just going to increase the count by 55?