I solved this problem. I was lucky because the intermittent failure to start when hot happened at the BMW Service Centre. So, the fault came up on the reader.
It was the Camshaft sensor. Clearly it was breaking down when hot.
New sensor fitted. No more problems!!!

Sorry to burst your bubble John. The fix for the problem described here is the steering column ignition switch. The problem we have been working on has no rhyme or reason hot, cold, day, night, first start of the day, not the first start of the day, rain, dry, full moon, new moon. . . . . .

Since cleaning mine back in January I have had no problems starting what so ever. Prior to that we and several other people on other boards have tried numerous other fixes. The ignition switch was the last thing I and several others needed to touch.

Actually, the cam shaft sensors don't come into play until after the start cycle has completed (roughly 10-20 sec after your first turn the key). They are also fail safe, if one fails the computer will use the other and adjust accordingly. It also sets the light. If both were to fail the computer then goes into fail safe mode and dumps the oil pressure from the actuators. The result is a noticable lack of power. Oh, and a light.

I would not be surprized if your starting problem comes back. If it does, go back a couple of pages and you'll see a description on how to completely correct the problem.:thumbup:

Cheers,
Steve

OK last post on this problem. The cranking but no starting came back again. I disassembled the steering column covers, again, cleaned the ignition switch, again, starts every time again. The square connector to the switch had visable corrosion on the contacts. Cleaned that up too. I'm ordering the switch tonight.

That's all I have to say about that.

Thanks to all of you guys for an informative thread.
I have suffered with this problem intermitently with my 02' 3.0d.
As with you guys I noticed better start ups during the cold or after leaving the vehicle for a few hours.

I took mine into the stealer (lol! I like that 1), and they couldn't find a thing just gave me a new 'purse' key (slim black plastic key) and wrote the problem off as my original key having some sort of fault!

Anyway, since reading the ig swicth maybe at fault I am looking into giving this a clean as Supersteve directs failing that maybe I'll change it out.

My X doesn't die as some have described, but it didn't start for nearly 2 days when I first experienced the problem! Since coming out from the stealers (3 months back) I have not had the issue arise until last week. At which point it didn't start on 3 seperate occasions on the same day, very embarassing to say the least! Happy to say that it was limited to the one day, but obviosuly I assume this will get worse and more frequent if left to its one devices...

I will try the contact cleaner route, failing that probably change out the ig switch.

Thanks again for a very informative thread guys! Hope it will help me resolve one of the 3 problems with my X.

I have been having the same problem on my 01 4.4.

From reading through all 12 pages it seems the first thing I should try is cleaning/replacing the ignition switch.

Does anyone have the part number for this?

If the switch is located in the steering column, do you access it from inside the vehicle?

My X quite often also makes a loud, embarrasing and strange rattling sound when it does actually start, sounds like something is loose. Anyone else have this happen?

Just replace the ignition switch - less than $100 On my 2000 x5 (built 11/99) PN 61-32-6-901-962. I followed the procedures outline in the link below - Took me about 30-45 minutes - slow as there is not much space and just to be careful.

http://www.bimmerboard.com/forums/posts/244045


NOTE: Credit to Supersteve! and to the author of the link!

Faccen1,

NBX's post answered most of your questions. That's a great link by the way. Thanks NBX.

The one I would like to address is the rattle on start up. It's not normal; but, it's ok.

The valves are what is rattling. After the engine shuts down if one (or more) of the valves are being held open by the position of the cam and the lifter for that valve leaks down it will rattle on start up. It is only bad if it doesn't stop within a few moments from start up.

My 01 X5 4.4 with 132000 miles does it occasionally. My brother's 740 4.4 with 240000+ miles does it also.

Does it sound bad? Yes
Is it doing damage? No
Can it be fixed? Yes
Is it worth the money and effort? No

These engines have 4 vavles per cylinder. Each has a lifter, times eight cylinders. That means 32 lifters. In order to find the correct lifters to change they must be pulled from the engine and put into a test rig to have them leak tested. Do you think most dealer mechanics will invest that much time??? No, they'll change all 32 lifters and hand you the bill.

Every time you hear that rattle on start up just think of all the money, frustration and time you saved by not chasing that ghost.

NBX - thanks for the link, I will be ordering the igniition switch today.

Supersteve - thanks for feedback on the rattling noise. While my X was still under warranty I had the dealer try to fix it. They replaced:

1. Water pump
2. Timing chain
3. Alternator
4. Battery
5. Vacuum hoses

After doing all this and still having the noise they gave up. I will definitley take your advice on not pursuing it further. Changing all 32 lifters is crazy. Thanks again.

Starting Up
 

Ok after reading all 12 pages, my 2002 4.6i X5 (60k miles) is starting to have the same problems (not always starting on the first turn, it doesnt do it that often, but it is kind of embrassing).

I will take it to the AutoZone store to see if I get any codes & then try switching out the keys to see if this helps first, if not I'll try the cleaning method (need pictures so see where you guys are talking about, Im new to the forum & only had my X for about 3 months, I have no idea where certain parts are at). If this doesnt work I'll try changing out the ignetion switch & use the pictures that were provide in the link.

By the way this is a GREAT SITE!!

I just read all 12 pages and I want to thank you for the info.I have this problem for so long,I was going to sell it,but the car is in so good shape I will give it another try.Will work the ign. first then sensors and relays.The mechanics have made too much money from me allready.Thank you for this post.Rafael from Puerto Rico.