04 Maxima SE cranks but won't start
 

Changed the valve covers and spark plugs because the car was leaking oil, but when I tried turning the car on it cranked but didn't start. Made sure all sensors and grounds were in place. Put it on a scanner but it didn't throw any codes. Changed the CKPS and the cam sensor and then also the fuel pump. Already checked the relays and the fuses and they're all okay. Managed to get it to start twice but the engine shut off in a matter of seconds. The fuel pump is working and has pressure, but my spark plugs aren't sparking. What should I do??? 😓

Since this happened after you worked on the car, there is probably a wire harness connector that you unplugged and didn't get it to lock together when you re-connected it.

I would remove the intake plenum and other components just like you did when you removed them to replace valve cover gaskets and sparks plug. I bet you that you will find some electrical connection that you did not reconnect.

We'll I had all of those checked, even checked for the ground wires to be connected right. My mechanic says it's probably the ECU because when he had checked the relays there was one that was burned up and after he replaced it the car still didn't start. He said maybe it had to be when I plugged the battery back up after changing the valve covers because he says he also found another fuse on the wires that connect to the positive pole burned up. So something happened when reconnecting the battery that fried the relay, fuse and perhaps the ECU.

A friend of mine told me the same thing but I had two different mechanics make sure that everything is hooked up. Thanks for the tip tho

It turns out that the anti-theft system had locked the engine. All my car needed was a reprogrammation at the dealer. Problem solved. ��