Hi. I'm a newb here. have a 2005 cavalier. got the car with a bad engine/head gasket. Swapped motor and I can't get rid of this misfire. p0300 code. wiring looks ok. compression ok. fuel pressure within spec. swapped the ignition module and packs, didnt help. unplugging injectors didn't help.
if I start the car, it'll run fine for several minutes then suddenly start to misfire and barely run. I changed the ECU, wouldn't start unless I did the 10 minute key ignition on, (theft system), then started up and acting the same way. replaced the crankshaft sensor also.
Is the relearn process performed at the dealer a must?
any help would be appreciated.
no its not, if its starting and running, then you did the relearn procedure. correctly.
check the plugs?
check the fuel, possible clogged fuel filter? bad gas maybe.
changed fuel filter, plugs, and new gas.
I'm getting mixed answers about the relarn for ECU/crank sensor. What i did is the basic 10 minute key on thing, when you change cluster...that kind of relearn.
What about flashing the ECU or whatever its called. Junk yard said the ECU needs programming.......
Sounds like the ecu may have not been flashed for your particular car? There is no crank re-learn that I know of needed for the ecotec cav. I switched PCMs when I installed my supercharger and never had to do one.
so it does in fact need flashing at the dealer?
You dealer should be able to flash (reprogram) the os on your ecm to the correct one for your car if it is indeed the wrong one. When you bough the ECM what car did it come out of?
a crankshaft positon variation relearn should be done. False p0300 will set if its not done. Don't think its causing the problem your describing.
you need a full function scan tool to perform the relearn procedure.
hmmmm. so a crankshaft position variation relearn wont cause the bad misfire I'm experiencing?
dealer wants about 140 bucks to program the ecm. sound right?
shop around...doesn't need to be programmed just set up with a full function scan tool. A independant may be able to do it if their scan tool is capable. 10min procedure. expect to get charged 1/2 labour minimum.
i know a mechanic with a Solus scanner, would that be sufficient? i'm not exactly sure what i will be asking for from him.
ask if his scanner can perform a crankshaft position variation relearn procedure for an 05 cavalier.
