K04 build... Having issues, engine won't crank.

[MechanicalDream]

Just so we are clear, I am working on a 2006 Audi A4 2.0T Quattro 6spd Engine Code BPG.

So its been a long week in the garage... I removed original engine, and put in same BPG engine from parted out A4, built with EVOMS intake, JE pistons, Integrated rods, S3 injectors, upgraded APR HPFP, K04, Southbend Stage 3 clutch, lwfw, stern engine mounts, front mount intercoole ... Low mileage on rebuild. I also (tried to) use the ECU that was out of the other A4.




Needless to say, all electrical systems are connected, haven't noticed any fuses missing/blown. Engine is ready to fire.

Attempt one, starter doesn't even turn... I look on the dash and instead of the mileage it says SAFE. So I figure that the immobilizer has been enabled due to the different ECU

I plug my old ECU into the harness, mileage is reading on the dash after doing this, engine still wont crank.

Next, I swapped the starter with the old one I had that I knew was working. Still no go.


At this point I'm wondering if it needs to be reprogrammed for my car to accept the new engine. Does anyone know if I would need to reset the ECU to fix this problem, or could my problems lie elsewhere?

[MechanicalDream]

Okay, update. Since the key, cluster, ignition, and computer were all matched, I could rule out any of those possibilities. I knew since it wasn't cranking that it lied within the starter circuit. I tested the voltage at the starter and it read just over 12V so I knew it was getting enough power. I had a few people tell me there was no relays in *most* starter circuits, so I had not thought of that being a possibility until I talked to my friend that works at a german auto shop. He said, "You sure as hell do have relays in your starter circuit, I'd swap those out and see if it starts, then we will go from there"

So I went home, swapped the relays in the ECU box, and voila, it fires right up. Now all I need to diagnose is the low oil pressure. Yee-haw!