No spark after replacing valve covers

welcome- sorry to hear of your problems. Did you change anything else besides the valve covers?

Thank you, no I didn’t replace anything after this. I also checked connectors to make sure everything was connected as well

Hard to believe there's no codes held in memory. What kind of code reader are you using? Any chance you triggered the immobilizer to damp the spark?

I’ve been using a snap-on Zeus code reader. A few days ago while cranking a cps code popped up but went away when I replaced the sensor. Still no spark though

I also don’t believe that the immobilizer is tripped, as there is no light on the dash and the key fob works fine. The fuel pump primes as well.

Sounds like you've been using the right equipment and asking the right questions. But let's go over the immobilizer question again. There should be a red flashing light on the dash indicating the system is active before startup, and the light goes out once the car is started.

I get no light at all when the key is in the ignition

I'm trying to help you by ruling out the immobilizer as a factor. The light should flash when the car is unlocked, and should go solid when locked. If you get no light at all when the key is in the ignition, there's a problem.

okay, I have the car at my work currently since I work at a non-Nissan dealership. I can go check tomorrow morning to see if the light is flashing when unlocked. I should mention that the previous owner installed an aftermarket security system which I removed and reconnected all the wires, but this was months ago with no problems.

I should also mention that I have the “Z1 vq fuel port” with the pressure gauge installed, so I am getting fuel pressure. I’m not sure if the immobilizer cuts fuel or not.

Update: there is no light on the dash when unlocking the car

ChanBlake said:

Update: there is no light on the dash when unlocking the car

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Unless you have a custom tune that removed NATS, I wouldn't rule out the immobilizer as the cause of your problem.

Any updates on this?

Took it to a dealership and it was a bad ground for the ecm. They replaced it and it ran horribly for about 20 seconds and then died with the fans staying on full blast

ChanBlake said:

Took it to a dealership and it was a bad ground for the ecm. They replaced it and it ran horribly for about 20 seconds and then died with the fans staying on full blast

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Not sure I understand- the bad ground resulted in the ECM not functioning? After the ground was cleaned and reconnected, the ECM ran for a short time and then stalled? Did you get it started and running reliably after that?

The bad ground resulted in the ecm not sending a signal to the coils. The dealership fixed the ground and told me it was ready. I started it and it was running rough, I drove about 30 feet and the car stalled and died so I just left it there for them to fix. This all happened today so I’m not sure exactly what’s wrong now yet.

So, after the Z stalled, it wouldn't start again?

Yeah, it wouldn’t start and the fans were on full blast with the key in the ignition, so I’m assuming I have a larger ecu problem on my hand but I’m not sure. I’ll keep you updated.

Update: a bad ignition coil caused a misfire and blew the ecu fuse