What is the problem of engine wont start but has cranking in bmw car 5 series e39...

run the fault codes
check that the immobilizer is operational ( fob key battery)
check for broken timing belt/chain
check crank/cam position sensors
check the ignition control module

When were your spark plug wires last changed? And have you checked your ignition module? Crank shaft position sensor is another item to have checked.

If you've checked the fuel system, then check the "spark" end of things

BMW wont start, electrical problems FIX! - YouTube

? 2:45
https://www.youtube.com/watch?v=L8akXREk80w
Jul 18, 2014 - Uploaded by DeviledDevin
BMW wont start, electrical problems FIX! .... After 6 days of reading and watching DIY videos might just open a service bay for Bimmers. ... the ignition refused to transfer current to engine after few productive cranks leaving me with an unfinished ... Now comes the big question: where can I buy this product?Missing: x1 ‎xdrive20d

Summary of engine cranks but won't start threads (gas air spark ...

www.bimmerfest.com > ... > 5 Series > E39 (1997 - 2003)

Nov 15, 2013 - 25 posts - ‎10 authors
any of which would cause an engine to not start - but - there wasn't a good ... See: How to test compression on a BMW E39 V8 engine (1) and on the I6 engine (1) ... etc., but who don't post codes from an OBD scanner with their question (1) ..... Likewise, if the fuel pump relay had an electrical short or open, ... Hard to start when engine is warm
23 posts
Mar 29, 2013
X5 sometimes crancks but won't start
25 posts
Oct 10, 2012
More results from www.bimmerfest.com

Did you check the cranck shaft pulley. It has a rubber inner and when this parish it does not turn and the sensor cant read the pulley

is the your car engine cranking when you try to start, first check spark plugs ignition coils, remove one ignition coil and spark plug fix the spark plug in to the ignition coil then connect ignition coil to wiring and keep spark plug body touching on ground of engine head mettle parts, ask some one to crank engine then you can see is the plug sparking or not, do the same way to all the coils and plug otherwise you have to buy a ignition spark tester, is the all the coils and spark plugs are OK then check the fuel pump, it's sitting in under rear seat, before that do one thing disconnect oxygen (O2) sensor wiring and crank engine, the thing is if your oxygen sensor completely dead fuel pump will stop working, if engine start after disconnect O2 sensor, replace new O2 sensor, otherwise need to check fuel pump relay fuse and fuel pump. is this information helped you? please vote me and give a comment.

Most probably its a low fuel pressure related problem.Get the fuel pressure checked.If its low then this is faulty fuel pump and clogged fuel filter issue.the other possibilities are,-----

A car that cranks over but doesn't start, in many cases will be due to a bad fuel pump, a broken timing belt, an inoperative cam sensor or crank sensor. Also this problems are related to faulty spark plug. Check the spark at spark plugs when you start the car. Do you notice any spark. Actually you should see. If in case there is no spark then it's a spark plug problem. Also the coil pack gives power to spark plug. So check the voltage at coil pack. It will show 12 volt.If there is no voltage noticed at coil pack then its faulty coil pack that has to be replaced.If all the possible options checked out ok then check the car starter. The starter gets power from battery to start the care. If the starter is faulty then it will not let the car to start. Also check and confirm that there is fuel in the car. If it very low fuel then in some cases this causes the problem. Also check and confirm that fuel pump is functioning properly and the fuel filter is not clogged. One of the easiest ways to check for a fuel pump related problem is to spray a little starting fluid into the air intake while trying to start the car. If the car starts momentarily, then there's a good chance the fuel pump is not working or the car is out of gas. You can also listen for the fuel pump's humming sound when the key is first turned on. Also if a inoperative fuel pump is suspected, a good technician will always check to verify there is power and ground being supplied to the pump, to eliminate the possibility of a bad relay or electrical issue. Fuel pressure can be checked with a pressure gage and if there is pressure, pulse can be checked at the fuel injectors in several ways including the most common, with the use of noid lights. If the injectors don't have pulse the engine won't start. ---------- This troubleshooting tips will help you to solve the problem.Thanks.Helpmech.

check for a spark if no spark and engine cranks ok then renew the ignition module

If it doesnot crank at all look for starter/starter relay/starter relay fuse. Most probably wiring coming to starter is loose, try to tighten it more (push towards starter). Also I would check antiteft system (if it is provided for your car) as some BMW have immobilizers.
If it cranks no start look for spark plugs, wires, distributor cap, coolant temperature sensor, O2 sensor, fueling system (fuel pump cutoof switch, fule pump relay, fuel filter).
Please kindly let me know if you need more information, or kindly provide me with more details to assist you better
Good Luck

i would check the fuse for the fuel pump and the relay.