E39 540 Not Starting

E39 540 Not Starting

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Discussion

anonymous-user

Original Poster:

53 months

Wednesday 2nd September 2015
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Hi All,

I am desperately in need of some help

I have a 2002 E39 540i with about 130k.

All has been fine until last week when I went shopping. I came back to the car and it started but was very lumpy, it then died as soon as I took my foot off the throttle. It then refused to start, but cranks fine

After an initial google and some advice my mechanic ran diagnostics on his computer, crank sensor seemed to be fine (could see a reading when cranking the engine) but nothing from either cam sensor. He ordered a new one to see if one was at fault but nothing doing

He seems to be a bit stumped now and is coming back later to look again. Is there anything I can suggest he looks at? Anyone had something similar before?

Collectingbrass

2,198 posts

194 months

Wednesday 2nd September 2015
quotequote all
Have you checked the coil packs? Is the fuel supply system OK? Filled it with diesel recently? Is the battery recent and fully charged?

TBH unless you've a specific fault code, and even then even with one as vague as cam position sensor faults I would be checking the basic requirements of a combustion engine before I started messing with sensors.

anonymous-user

Original Poster:

53 months

Wednesday 2nd September 2015
quotequote all
Collectingbrass said:
Have you checked the coil packs? Is the fuel supply system OK? Filled it with diesel recently?

TBH unless you've a specific fault code, and even then even with one as vague as cam position sensor faults I would be checking the basic requirements of a combustion engine before I started messing with sensors.
I havent checked the coil packs, will check fuel pump (although would hope he has done this already)

I dont think I have filled it with diesel

anonymous-user

Original Poster:

53 months

Wednesday 2nd September 2015
quotequote all
I did put fuel in that day though

Easiest way to confirm? Dip the tank?

rb5er

11,657 posts

171 months

Wednesday 2nd September 2015
quotequote all
anonymous said:
[redacted]
I think checking the receipt is probably easier.

anonymous-user

Original Poster:

53 months

Wednesday 2nd September 2015
quotequote all
rb5er said:
I think checking the receipt is probably easier.
Didnt get one, paid at pump, the station are going to check the transactions though

anonymous-user

Original Poster:

53 months

Wednesday 2nd September 2015
quotequote all
Guy seems to think it might be ECU (or ECU wiring) as he is getting nothing from Cam sensors even with new ones fitted

Depthhoar

673 posts

127 months

Wednesday 2nd September 2015
quotequote all
Check the fuel pump. This is a common problem on the E39 M5...sudden stranding, non-start etc. A knackered pump won't throw a code (a dodgy fuel pump relay will produce a code though). Take out the back seat (done in seconds) and listen for it energising when going through a starting procedure. The pump is located under where the off side rear passenger sits.

anonymous-user

Original Poster:

53 months

Wednesday 2nd September 2015
quotequote all
Depthhoar said:
Check the fuel pump. This is a common problem on the E39 M5...sudden stranding, non-start etc. A knackered pump won't throw a code (a dodgy fuel pump relay will produce a code though). Take out the back seat (done in seconds) and listen for it energising when going through a starting procedure. The pump is located under where the off side rear passenger sits.
He said he had checked this but will reiterate

S. Gonzales Esq.

2,556 posts

211 months

Thursday 3rd September 2015
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Probably not your issue, but it's worth noting that the fuel filter isn't on any service schedule. At 130k it might be worth fitting a new one.

Depthhoar

673 posts

127 months

Saturday 5th September 2015
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Did you eventually find out what was causing the non-starting?

anonymous-user

Original Poster:

53 months

Saturday 5th September 2015
quotequote all
Depthhoar said:
Did you eventually find out what was causing the non-starting?
No not yet frown

gowmonster

2,471 posts

166 months

Saturday 5th September 2015
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Diesel nozzle is bigger, i'm sure when it didn't go in you'd have noticed and went wtf.

my 330 went very rough when the air hose split. it was after the air sensor. checked that?

anonymous-user

Original Poster:

53 months

Saturday 5th September 2015
quotequote all
gowmonster said:
Diesel nozzle is bigger, i'm sure when it didn't go in you'd have noticed and went wtf.

my 330 went very rough when the air hose split. it was after the air sensor. checked that?
Oh yeah double checked with the garage and it was defo unleaded I put in

I've asked the mechanic to check all the basics like fuel, spark and mentioned the air hose as it seems to be common.

He replaced the Cam sensors but was still getting an open circuit so isnt quite sure

gowmonster

2,471 posts

166 months

Saturday 5th September 2015
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anonymous said:
[redacted]
could be a break in the wire from the cam sensor bit where it plugs into the wiring harness.

anonymous-user

Original Poster:

53 months

Saturday 5th September 2015
quotequote all
gowmonster said:
could be a break in the wire from the cam sensor bit where it plugs into the wiring harness.
Yeah I think that's his suspicion too, its just the time involved in finding it really, sure he'll get there but we are on a ferry on Thurs so are currently looking at alternatives, just stty timing really

helix402

7,832 posts

181 months

Saturday 5th September 2015
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I don't think the cam sensor failing will cause a non start. If it fails the ecu will use the crank sensor output to calculate a rough value/default value for the cam position. This will cause a longer cranking time-but not a non start.