Had this issue with an e36. Alternator was seized. Try seeing if engine cranks freely

 

Thanks for your help, no problem with alternator and it is charging well

 

I tried to simulate a new ground with jump cables but no improvement.

 

I vote starter...if CAS is telling you about a starter issue I would think it's more your friend than enemy.

Your motor is not seized, right?

 

Yes motor is fine and sometimes car starts, especially after a full charging battery but only once.

I will remove starter soon which is a PITA on N62 V8.

 

My bad, I forgot you said it will fire up. yes it is, removing the motor mounts (the one off the block and one on the subframe) might help with space under there. hoisting/jacking the engine up might help too. I feel as tho the subframe will be a pita to work around. I pulled the starter off my dead TU when I pulled the motor and did not envy those trying to remove that thing still in the engine bay!

 

If bad ground trick using jumper cable to improve engine to chassis ground doesn't work, likely bad starter. Have to make sure engine rotates and nothing seized and battery good...

 

Check and clean the battery connectors and all electric connections on the car - especially the ground connectors.
Check also the electric connections to the starter -positive and negative or ground.
And of course, test the battery, recharge it or replace it.

 

I'd check your engine control module integrated supply module IVM. That fixed my issue which was similar to yours.

 

It is pretty clean :

I have another N62, can I test with the other one ? No coding needed ?

 

I tried with another IVM module no improvement

 

I could start the car to bring it to my garage and removed the starter BUT I'm confused because it seems working fine.

Is it possible that it works on the workbench but does not have enough strength when installed on the motor?

 

If alternator is not spinning freely for full rotation it can bind the starter enough to prevent starter from rotating engine. Again, had the problem on my e36.

 

Removed the belt and alternator is spinning freely no problem.

 

Last test I could connect starter directly to the wiring of the car, and adding a ground between starter and engine.

 

Result :

Starter is working with ignition button of the car.
So can you confirm it can work outside of the motor but not enough strengh to start the V8 ?

 

Yes, your starter is good and fine. But it is not getting the right signal from the ECU to start up.

 

Ecu send right signal because in the last test starter matches with start button.

 

Problem solved, bad starter.

New one (bosch) was around 150$.

I decided to open it, clean it, grease it, and change the brushes holder with new brushes of course.

Car starts like a charm ! Thanks