The Advanced Complicated Mysterious Engine Misfire Story

899ccs wrote: here is the deal dude and i know you are not gonna want to hear this but you spiked your ECU.
based on the info in your posts and others in this thread, you stated the car was running perfect and out of boredom you decided to grease the secondary ignition which is fine, then you said you greased the primary power supply wire connector to the ignition coil which also is ok. then you shortened the wire harness entirely by cutting the harness and splicing it with butt connectors. here is where we got a problem. you state that the car runs fine cold? thats because the engine managment system is in open loop, the critical sensors here are CAS, CHTS so we can assume that these are working ok as is your MAF because your engine will rev past 2000 rpms. so what do we really have left to work with…well coolant temp, egr position, purge solinoid..throttle position sensor…fuel pressure regulator control solinoid and on and on …but what i am interested in is that after two minutes it begins to missfire. after two minutes the O2 sensor has warmed up along with the CHTS, the ECU senses this and steps into closed loop. The ECU has basically sections of data that it looks at based on info recieved from the various sensors, they call it strategy. this strategy is then applied to the various actuators aboard your vehicle in real time (meaning damn quick). It is all in an attempt really to assure your engine runs at or near stochiometric. this is really just an attempt to protect the Catylitic convertor so it can keep your engine from polluting our air when it develops a misfire and/or has fallen out of tune and the vehicle continues to be operated on a daily basis. The ECU is know controlling the injector p/w, AIC or Aux Air whichever you have, the egr circuit if you have one still and the primary ignition as well as timing advance/retard and other systems of lessor interest to us at the moment. 1slick2 said something very interesting and paramount in one of his posts, he said the Stock ECU is crap basically, and when he went to larger capacity injectors and a stand alone, (meaning an after market essentially custom made Engine Managment Computor, that his VG30 ran smooth like no other he has seen before or since. When you cut those wires to the primary ignition most likely the engine was still near operating temp {just guessing here} or the key was left on ?
or both.? if you had disconnected the battery before you cut, then the aforementioned would not matter… any way i believe you damaged the ECU"s ability to either recieve data or apply
it's ignition strategy. to test this theory take your car out and drive on the highway. make sure she is at normal operating temp. when you reach approx 70mph in top gear you should be around 3000rpm, accellerate hard for five seconds. the ECU will drop out of closed loop and and allow injector p/w to go wide open and ignition primary voltage and ignition timing to operate at solid base values with no ECU influence. the engine should pull hard with no sign of a problem....if so go home and replace your ECU and next time DISCONNECT YOUR BATTERY BEFORE YOU HACK