p0300 code after build

[busafastone]

i am getting a p0300 code after i did heads,cam,roller, rockers,mds cap and rotor and wires and 36 lbs injectors,but the car runs lick an animal any ideas why

[Camaro96]

i am getting a p0300 code after i did heads,cam,roller, rockers,mds cap and rotor and wires and 36 lbs injectors,but the car runs lick an animal any ideas why

That's a misfire on multiple cylinders. Ma want to check your plugs and plug wires. And it also would reset the code

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[Injuneer]

How big is the cam? Misfires are detected by looking at the precise rotational speed variations of the crankcase, and comparing those variations with the KNOWN pattern for the STOCK engine. A larger cam alters the crankshaft rotational speed variations, and they no longer match pattern of the stock engine. That could be causing the code.


@popo8 Maybe this should be moved to the engine tech or tuning and PCM forum?

[popo8]

How big is the cam? Misfires are detected by looking at the precise rotational speed variations of the crankcase, and comparing those variations with the KNOWN pattern for the STOCK engine. A larger cam alters the crankshaft rotational speed variations, and they no longer match pattern of the stock engine. That could be causing the code.


@popo8 Maybe this should be moved to the engine tech or tuning and PCM forum?

Done

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[busafastone]

have new wires and plugs ,cam is 218/228dur 112ls 570/566lift with the 1.6 rollers

[busafastone]

car runs great and pulls like a freight train

[busafastone]

ANYONE?????????????

[superspirit]

I would check for a vacuum leak, I fought a random p0300 for months on a TPI engine I had built, turned out under cruise situation the vacuum was opening the disconnected EGR valve through the hole in the bottom of the pintle. Just food for thought. maybe during the cam install a small vacuum leak arose?

[Injuneer]

ANYONE?????????????

Did you not understand my post? The misfire code could be caused by the cam, not an actual misfire.

The cam changes the slight impulse variations in crankcase rotational velocity, and the pattern no longer matches the pattern the misfire diagnostic the PCM is expecting. If it runs well, no sign of misfires, the misfire code is NOT the result of actual misfiring.

[busafastone]

ok but sometimes when it is not under load it flashies is there any way to test this our correct it in the programing