Stuck!! X5 3.0i starting issue - Intermittant Cranks well but doesn't start in AM

[Ratman2356]

Hi folks, 03 X5 3.0i auto 100k miles. Was running fine until yesterday. Would not start although it cranked strongly during starting attempts. I came inside to look up some info and went back out an hour or so later to try to check some onboard diag info. Tried to start it first and it half caught on the first try and then started the 2nd try. I drove it to autozone and they checked it for codes. None found. Checked battery, 41% but tested ok. Drove it around a bit and then home. Started up fine a few more times through the day. Put the charger on it through the night to make sure battery was full from all the cranking I did on it.

This morning same thing as yesterday. Will not start but cranks strong. Info: Installed new battery and alternator 3 months ago. Just got it back from shop last week after having CV axles, A/C system and thermostat replaced.

I noticed that the battery light stays lit while trying to start it. I have never noticed this in the past but it always started right up so not sure I would have. Can anyone tell me if it is supposed to light up while cranking? I am wondering if it is indicating a failed alternator again although it did not light up at all yesterday while driving.

Any other things to check that maybe the mechanic might have knocked loose or not tightened correctly during those procedures that could cause this?

I thought maybe Crankshaft sensor but if I understand correctly, that is an all or nothing thing and it would not have started at all yesterday. Fuel pump going out is another possibility which is why I am trying to eliminate the alternator first as that batt light is only thing I have to go on right now. Can someone check their X5 and see whether it stays lit while cranking the engine over please?

Pulling my hair out here. Thanks!

Rob

[Ratman2356]

UPDATE: I continued my research and came across an occurrence where another BMW owner had similar symptoms. He had came home and went back out later to get something out of the car and left it unlocked overnight. The car would not start the next morning. After banging his head against a wall for a few hours like I have, he thought to try locking and unlocking the car with the remote to reset the security system. The engine started right up. No word on whether this solved it for good or was coincidence. I had nothing to lose so tried it and it started for me. I went and had the alternator tested and it tested ok. Onboard voltage showed 13.5-13.9v while driving to the store and back.

Hoping this is all there is to it but still looking for any input other owners may have.

[Ratman2356]

UPDATE 2: Not sure I am expecting any replies at this point but maybe when I get this figured out this will help someone else some day. Same problem again this morning so it wasn't the security system. Temp is 28*, started the first day at 31* so I don't think it is cold related. I am about of clues.

If it was fuel pump related or fuel relay wouldn't it run like crap after it started? It doesn't tho, it purrs like a kitten so seems to eliminate fuel, ignition coil issues. Already checked batt/alt charging system. Any more ideas?

[SlickGT1]

There were other people with similar issues. Some have had this problem fixed by getting the DME updated at the dealer.

[diyanich]

Change the ignition switch,don't wait,as it's gonna get worse.
Once I was sitting on the parking after work for 30 minutes and cranking.
I pulled the fuel pump fuse and it started.
When I got home,I removed the Ignition Switch and cleaned it.X was starting without any problems while I was waiting for a replacement part.
Had the same problem on my e36 series,but I sold it before I knew what was causing the no start problem.

Originally Posted by Ratman2356

UPDATE 2: Not sure I am expecting any replies at this point but maybe when I get this figured out this will help someone else some day. Same problem again this morning so it wasn't the security system. Temp is 28*, started the first day at 31* so I don't think it is cold related. I am about of clues.

If it was fuel pump related or fuel relay wouldn't it run like crap after it started? It doesn't tho, it purrs like a kitten so seems to eliminate fuel, ignition coil issues. Already checked batt/alt charging system. Any more ideas?

[Ratman2356]

Well I certainly appreciate the responses. I was really at a dead end. I will pursue both avenues.

I am curious as to why pulling the fuel pump fuse allowed it to start for you diyanich. I am not seeing the connection. Do you mean the fuse was bad and you replaced it?

[JCL]

First, stop worrying about the alternator. The alternator charges the battery, it isn't involved in starting or running. If you have enough battery to crank at reasonable speed, you enough battery to fire the ignition. The alternator is there to make sure you have enough battery next time, or the time after that.

Without reading the codes and seeing if anything is flagged, everything is just a guess on our part. So, if you want the real problem identified, get the codes read.

Having said that, the ignition switch is a common failure point that can result in cranking without firing. That is because it uses separate contacts, and when it fails sometimes the cranking part works (it makes contact) but the ignition or other system doesn't get contact. Search on ignition switch here to see multiple threads.

Essentially, if the engine is cranking, you just need spark and fuel to fire. You don't have one of those. Complete diagnosis would include checking fuel pressure, ignition power, and so on. And remember that far more problems are electrical rather than fuel related, statistically, so start with electrical first.

Good luck

Jeff

[JCL]

Originally Posted by Ratman2356

I am curious as to why pulling the fuel pump fuse allowed it to start for you diyanich. I am not seeing the connection. Do you mean the fuse was bad and you replaced it?

Yes, it had to be replaced to run. He would have pulled it and reinserted it.

Three possibilities.

1) Bad contact on the fuse, remedied by pulling and reinserting it.
2) Reset something in the DME, ie the computer thought it had a problem and this reset it. Not sure how.
3) No connection, purely coincidental.

[Ratman2356]

I have time to mess with it so went out and pulled the glove box and pulled the fuel pump fuse. Was ok, cranked it over a couple of times, put the fuse back in and it started, ran rough for a few seconds before smoothing out. So sounds like it is same issue as you had. How in the world you figured it out is beyond me though. Heck of leap from fuel pump fuse to ignition switch. Thanks so much for sharing your experience, would love to hear more about it so hopefully I can understand the connection.

[Ratman2356]

Thanks JCL, as I said there are no codes to read. It didn't throw any faults. I was focused on the alternator because of the battery idiot light that according to the manual means a problem with the alternator. I appreciate your input tho