So working on tuning still and continue running into CEL p0300. currently tuning on just osiris as we are trying to work this issue out before getting the haltech in and going all out. reguardless of timing and afr p0300 continues to come out. Begining to think the extra noise from the stroker and cams is tripping the stock sensor and throwing the code. but wanted opinions from the locals.

side note. build is 4.1L HR with gtm twin kit 3076r's and id 1000's and cjm twin hangar set up.

 

misfire is not detected with a knock sensor. it uses the crank sensor.

why not just decrease the sensitivity of the misfire table in uprev, esp if you dont think its real misfire? Thats the best feature they have going.

 

Was worried it was real missfire but I find it hard to believe now with the timing completely retarded and afrs perfect. Will try that after I Change plugs tonight.

 

too little timing will also cause misfire and really high egts.

you will see misfire on your afr logs as well

 

I will have to take a look at the Afr log and see then

 

I have only thrown p0300 if it is doing so quite badly. Stock misfire tables. I've never had a problem being able to detect misfire with my own senses. Maybe get someone more experienced to listen in while you do pulls.

 

check wiring connections at the connectors for all the injectors and coils. Those things can push out just enough to cause a bad connection. Mine always threw a 0300 even though the connector was only loose on #2. Not sure why it never threw a 0302 but it didn't.

Also, like rich said, too little timing will misfire and causes just as many problems as too much.

 

hmm thats one thing i havent checked, ill check all the connections this weekend when i change the plugs. i don't think timing is an issue we didnt retard it to a point where it would be unhealthy just took it down so it wasnt aggresive at all since this code kept appearing. had the tuner go over the logs aswell and no signs of missfire in the afr. so im assuming sensor or loose connector at this point. or maybe possible fouled plug. they looked fine when i checked them about 800 miles ago though so im not leaning on the plug possibility to hard.

 

also the cel comes and goes. itl be on for a day or so and then disappears on its own. i assumed if it was a true missfire that code didnt go away and the cel stayed on?

 

If it doesn't sense misfire long enough it will go out. It's not a persistent code.

Also keep in mind it might not be misfire under full load... rather it could be a idle or light/part throttle misfire on tip or cruising which you might not feel in boost or see on the dyno. If you're running aggressive cams this could very well be the case.

 

typically its under a hard pull in the upper rpm bands it the cel flashes and then pops up a few mins later. motor sounds strong though and the logs aren't showing anything unsual which is why im confused. if it is a possible loose connector could be the engine flexing and tugging on one of the clips to the injector or something? im sure the plugs will elude to wether or not its a real missfire this weekend

 

CEL flashing means a spark misfire and un burnt fuel is being dumped out, spark misfire maybe to rich or a cracked spark plug, or the coil driver can't support the spark on the top end, try a cylinder drop test
1. hold RPMS at 2000RPMs,
2. kill 1 cylinder, can disconnect coils or use ECM controls to disable cylinders
3. without giving it more pedal see what the RPMs drop to about 50-100 RPMs is normal
4. repeat for all cylinders
5. the cylinder that drops the LEAST amount of RPMs is ususaly your bad cylinder...

 

You can kill each cylinder with cipher's cylinder test... way easier than pulling wires (it appears the OP has osiris). might as well set the idle to 2krpm during the test to eliminate pedal error.

 

the flashing under WOT full load was what mind did when an injector connector had a loose wire in it. Under load the resistance was getting too high on the loose connection causing it to drop connection and misfire. Drove perfectly fine to work and back but acted up when i was wot hard.