Yeah which would indicate to me that, at least in your case, the P0300 code has nothing to do with transmission harmonics. As you prolly already figured out, most likely the lean condition is causing detonation. The real question is, why is your fuel getting cut?

Some times a P0300 code is really a P0300 code!

 

The key!!

 

Isn't fuel cut = leaning out? I mean they are both creating a condition where there is a lot more air molecules per molecule of fuel than there would be in normal driving. So that lean condition you see is the ecu cutting the fuel 100% from the engine until the problem it is detecting disappears. Does that make sense?

SC~

 

I've been doing some tuning using an ECU+. With my current state of tune my car will throw a P0300 when I first start driving after an extended cool down. If I clear the code after the intial CEL it doesn't come back under any operating condition even when I stop and restart the engine. I haven't backed out my fuel trim map yet to see if that is the issue or if it's a bug with the ECU+. Before I do I'll do some datalogging to see what the injectors, timing & whatnot are doing when it throws the code. If I find anything interesting I'll post back here. My issue could be a coincedence of tranny harmonics and the installation and tweaking of the ECU+, but I don't think so. I think mine is related to the AFRs I'm running at certain RPMs and operating temps.

 

Doug finally got my plugs, are they pre gap for the Evo or do I need to re gap them?
Thanks again...

 

I just came back from testing the new plugs, well bad news for me SES came back. Plugs were gap at .28 but with no luck SES came back at same speed, RPM, and trottle position. My next step now is to send my ECU to Al and get the Flash, according to him he fixed this problem. I'm not gonna wait for the reflash from Mits. coz according to my service tech who spoke to the tech line the so called reflash won't be available till the end of the year.

 

for those of you with an XEDE, and are getting the "p0300 random.....",
and think it could be the XEDE or stock ECU, ....I may have discovered a legitimate fix.
email or pm me...
my EVO is back, and not acting out anymore .
I'll let you know what worked for my p0300 "situation."

 

cokofellah Just post it dude, what's with the secrecy. I am also a bit curious about your linkage with the Xede, FAR more ppl have this CEL problem that have the Xede.

 

Man, you're not helping my hangover.....

Ok, now that I'm relatively sober, I guess my post did sound "restrained".
There's no secret to what I found out. TIMING was off, and that was just it buddy.
Made some adjustments to my box....and i guess I lucked out.

If you need more details, just email or pm me
I'm planning on having the box checked by the guys at Vishnu....they know more about this than I do.

The drive to work this morning was smooth.....hope it stays

 

I can't seem to find any solid information on this but does a P0300 get registered if excessive knock is sensed? The information I found indicates that misfires are detected by the ECU monitoring small variations in engine RPM that the ECU interprets as a misfire. When these variations in misfire are regularly repeated, then the ECU declares a misfire.

Does a knock in and of itself register a misfire or does the ECU also have to see an accompanying variation in predicted engine speed? As far as I know, I haven't heard of CELs being thrown when the ECU pulls timing due to knock detection. Maybe it has to be severe knock and timing pull back for a misfire.

Ideas?

 

No problem cokofellah, been there myself a few times.

There is a MUCH larger thread, I believe it's under the EVO/engine catagory regarding this issue.

Just some of the thoughts on the causes posted in this and other threads have been-

Bad and/or incorrectly gapped plugs

O2 sensor sensitiviy problem (I was told this one personally)

Transmission harmonics

Bad gas

Timing issue (per cokofellah in this thread)

A real misfire

Bad coils and/or wires

ECU has bad code (a fix may be forthcoming at the end of May)

Moon was 2/3 rds full with an ebbing tide in the Bay of Fundy at Noon on the spring equinox

In other words...well you get the picture, it's a problem, and Mitsu does know about it, and we are all waiting on a definitive fix.

Good luck to all of us in the PO300 club.