Hi: this is my first posting on this forum. I am currently restoring a European model 520i (E34) with the 24-valve M50 engine. Great car. It came straight from Italy with a Racing Dynamics modified engine, suspension and exhaust. Among the first things I did was a complete tune-up. I also put some Red Line S1 fuel cleaner inside the fuel tank as an extra precaution. The engine itself runs perfect. I noticed however the car always needs to be cranked 4 or 5 times before the engine starts, even when it's warm. Does this car have a cold starting valve like my old E23 728i that needs to be changed? If not what else could cause this problem. I also noticed the idle is a bit irregular. ARe those two things related?
Thanks,

http://member.rivernet.com.au/btaylor/technical.html#general

thanks for this impressive source of information. but where do I begin??? I mean is this a fuel system problem, or an electrical one? Can someone be specific about where to look?

m50 does not have a cold start valve. Suggestions... test battery, starter, and engine compression.

The battery is new, and I don't think it's the starter either. It feels like not enough gas gets to the ignition. After 4 or 5 times, it fires up fine. I read an older post that says once you turn the key you should wait a few seconds before ignition. Is that a normal thing to do?

Make sure that when you are cranking the fan is spinning fast enough if not possible battery. Maybe you should try doing a fuel pressure test, change your fuel filter, plugs. Or better yet crank your engine and have some one check each plug for sparks. You may not be getting proper sparks from the first few cranks. If sparks are good and fuel is good then look into your starter or battery, like one member said before.