The car failed to start a month ago. And it was started again by spraying spark fluid into manifold. However, it failed the emission inspection. Reason: Oxygen sensor not ready, EGR not ready, Catalyst not ready. The ECM does not have any error code. When I check the ignition timing with OBDII scan tool, it reads 63 BDTC from ECU when idle, and oxygen sensor reads as low as 0-0.1 volt at the same time. Using timing light ignition timing is unstable during idle. However, it becomes 0-9 BTDC when rev engien to over 1000 rpm, and oxygen sensor voltage becom normal (fluctuate at 0.1-0.8V). The specified ignition timing should be 8 BTDC. I checked the engine coolant temp sensor, throttle position sensor, camshaft position sensor, changed the oxygen sensor. Nothing corrected. I then checked the crankshaft position sensor. It turns out that the crankshaft position sensor does not receive any voltage (Should be 5 volt according to the Haynes repair manual), and disconnect crankshaft position sensor doesn't affect anything. So, I assumed the ECM has a problem. But the problem still exists after I replace the ECM. Any suggesionts? thanks