altima 2002 2.5L loss of spark after a few seconds of cranking, had been having random misfires on highway, then couldn't get past 1700rpm and now won't start. Both cam and crank replaced several times, bough 10 sensors, all tested good, got real nissan sensor, they are worse. hooked up oscilloscope, I can see signal coming out of both sensors nice and sharp when probing at the computer. Tried another ECU but can't get it to fire at all in that config. email me at***@******.***
JA: Does the vehicle stall at low speeds? Does it sputter?
Customer: does not start at all
JA: Are you fixing your Altima yourself? What have you tried so far?
Customer: yes DIY, already listed above
JA: Anything else you want the mechanic to know before I connect you?
Customer: this is a common issue on 2002-2006, everyone has faulty cam/crank sensors
it seems, but my sensors work just fine. I hooked up a logic analyzer to sensors and spark output, when cranking you can see spark fire on all cylinder but the spark signal coming out of the ECU goes away after a few crank rotation. It doesn't go away all at once but instead the ECU sends fewer and fewer of them until none. Battery voltage good. Tried with all coils disconnected, probing ECU spark output, I get the same thing, spark signal firing then disappears.