Problème démarrage 320i e36 (m50b20)

Here's a common starting problem on 320i, 520i, etc. models with the M50B20 single-VANOS engine. In my case, it was the internal wires of the crankshaft and camshaft position sensors that were exposed and touching each other. This causes a long starting time. Once it's running, everything is fine, but a healthy engine should start instantly. Note that if you replace the sensors, you absolutely must use Hall effect sensors, which have much more precise electronic control than standard sensors.