NB2 Cranks, does not fire. Bone stock after an engine swap.

I get power to the coils. Fuel at the rail. Cranks over but no start. No codes either. Immobilizer flashes once after I connect the battery, no flashes after that. Any ideas?

 

Car? Year? Engine management?

 

Sorry. Updated original post.
stock 05 after an engine swap

 

Are your plugs wet after cranking but not firing? Would help verify injectors are pulsing.

 

Use an OBD2 reader to look at live data while cranking. You should see RPM. If not, it won't inject fuel or spark, so you need to start there (crank/cam sensors), if it's not connecting the ECU, look for ground/power faults (relays/fuses). You can use an OBD2 reader to scan for codes too, but they're mainly for emissions purposes, it'll rarely tell you codes helpful during a crank/no-start condition.

 

It sounds like you’ve got power and fuel, but something’s preventing it from firing. Since you’re not getting any codes and the immobilizer flashes only once, it might be related to the key or the immobilizer system not fully disarming. You could try reprogramming the key, or if you’ve got a second key, try that to rule out a key issue.

 

Also, check the crank position sensor—if that’s faulty, it can prevent the engine from firing even if everything else seems in place. Lastly, you might want to double-check all the wiring connections, especially around the ECU and any grounds that could’ve been disturbed during the swap.



Let me know if anything stands out