Bmw X5 Starting intermittently

[Sharpster]

Just bought X5 on 55 plate fires up & runs perfectly until I have stopped whether it be 5 min journey or half hr journey when trying to start there nothing at all no cranking however all the dash lights head lamps etc all work bought new battery & it did fire up 3 times in a short space of time and thought problem was solved but after short journey back to nothing again. It will always start up but only after half hr or so or longer. Battery is charging certain fuel pump underneath rear seat is working
Relays are fine, I'm assuming because it runs perfectly when it does that it's not a fuel filter problem although guy I bought it off did say he'd never had one fitted, he did say he had same problem & concluded that it was a crankshaft sensor which he had replaced I personally think the problem is the same. Sods law cannot get it into garage to have fault codes checked but any advice would be appreciated. Disconnected battery today for about an hour when reconnected it fired up first time switch off engine then dead again, key seems fine, tryed shuffling auto gear lever from park to neutral etc all to no avail not until the magic half hr / 45min or so passes then it decides to start, out else I could try
Many thanks
David

[marti]

You say the crankshaft sensor was replaced...if its not a genuine one then thats where I would start, get the codes read.....it will probably also bang up a few codes so clear those go for a 5 mile run or so and re-read.....

[Sharpster]

Hi many thanks for your reply. Iam aware the crankshaft sensor has been solved & that there is no fault code showing for that now & for some reason I think the original problem remains unsolved as the symptoms are identical (I am good friends with previous owner) I think the camshaft fault coming up on his dash had something to do relating to something else electrical /battery issue as the car at the minute is coming up with transmission fail safe fault the 4x4 warning light has also appeared & a couple of of other warning lights ie abs tyre inflation etc, I've read that all these are thrown up when you have battery problems, but then again I've read all kinds of stuff so I'm guessing really. I know the battery I have put on may have to be reset or programmed which I have not tryed yet iam also starting to wonder if my new battery is up for the job was only £80 which I thought was quite cheap but that's what the guy in auto shop came up with, as mentioned will have to try and get it into garage but would like to try & rule a few more things out first cheers

[X5Sport]

E53 electronics predate the Intelligent Battery system so you don’t have to worry about coding the battery to the car. That came in from the E70 and beyond.

Bit of a long shot, but given you are getting all sorts of warnings, what happens to the battery voltage when you try to crank it? I’m kinda wondering if there is an issue with the starter itself - a known troublemaker on many BMWs fitted with that engine at that time.

If the voltage is dropping rapidly as soon as you try to crank then it could be a loose wire on the starter or earth braid, bad solenoid or even a bad starter itself (I’ve had two!). It might be that the starter circuits are failing when hot (as they would after using the starter) and once cooled a bit are fine. Does the starter ‘click’ when the key is tried but no start happens? If it does then the solenoid is trying to engage as it should.

Check that all of the wires are tight, and if your specialist has such a thing, get the starter current draw checked. It should be no more than 180A (2.2kW). If it draws much more then the voltage plummets and the electronics don’t have enough to work on so nothing happens. It also causes a shed load of false warning messages!

If mechanically minded and tooled up you can diy the starter for less than £200 - with rebate on old one - via somewhere like ECP.

If the starter is fine then it could be in the ignition immobiliser, or a bad key (have you tried the spare?).

[Sharpster]

Hi many thanks for your reply and advice. OK I have just went out earlier and it fired up straight away I let it run for a minute or so then switched it off, left it for a minute or so and it fired up no problem again I let it run a bit longer maybe 2 min and then switch off again done this 1 more time again no problem after letting it run a bit longer and switch off again went to restart it and nothing at all. Instruments lighting up radio on etc but no cranking at all but as soon as I tryed with jump leads if fired up straight away no problems. It has stood over night so engine was quite cold but as soon as it warms up that's when it has no response. Battery was putting out 12.5 volts when it was starting OK this went upto 14.5 volts when engine was running but was down to 12.2 when it would not start when trying to turn it over, as mentioned it jump started straight away when I tried. Hope this might be a bit more helpful on the problem iam no further forward really but sounds like a battery related /electrical issue if its firing up when jumped.
Many thanks for your help

[Leslie]

Follow the battery lead down to the starter there has been a case before where this was loose further down at alternator on an e70 but e53 may be similar ,if jump leads fixed it then it has to be power connection related.
The warm starting if it's a 3.0d is often the cam sensor which is on the front behind oil filter and easy changed.symptons are taking several/many goes till it will fire when warm but fine when cold. You may well have 2 separate issues.

[Alan Gunn]

Sorry but the cam sensor is not by the oil filter but at the front /top of the engine in line with the injectors sort of.
Well it is on my e53 3.0d.

[Leslie]

Sorry Alan that's oil filler cap not filter damn phones lol