No/intermittent start woes

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SWAUS6
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Joined: Wed Mar 18, 2009 2:13 am
Location: Bremer Bay Western Australia

No/intermittent start woes

Post by SWAUS6 »

Hi All,

Have the dreaded no/intermittent start woes...Left my car for a month and went to start it, found a flat battery, charged battery, and no start and then it did start once, and then ok immediately again, left it for a while and no go etc etc. Have looked at all the posts on the subject and found them very insightful - especially Bruceys freezing and painful experience.

However, my problem may relate to the crank sensor and wanted your valuable opinions please. The RHS crank sensor on my machine is cracked and broken at its top plug, and I have removed the plug join from the metal cradle and pushed the two together beside the cradle. The two times I have managed to get it to start (from cold) it runs a bit rough, which was a symptom of the plug coming apart before ( a few months ago and pushing it back together solved it back then, and its broken more since then). I have changed the fuel pump relay and understand that the problem may also be the main relay. The question is: Do you think the broken crank sensor plug is the source of my problem?

I can take some pics if its useful.

Cheers all,

SWAUS6
1986 635CSI, alpine white, Getrag CR, Australian delivery
2005 Land Rover Discovery 3, Zambezi silver, TDV6, manual
GripGreg
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Post by GripGreg »

It seems to me that you just self diagnosed your problem.
The ball's in your court, all you gotta do is hit it.
So hit it & see where it goes,,,,Greg
Hit the apex
in Long Beach, Cal
Buster/'82Euro6 Build Date 9/81
Rosallina/'80 528i Build Date 4/80
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SWAUS6
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Joined: Wed Mar 18, 2009 2:13 am
Location: Bremer Bay Western Australia

May have aced it

Post by SWAUS6 »

Thanks Greg,

Looks like I may have hit a winner with the sensor plug. It totally fell apart when looking at it today. Had been to my local BMW Centre, who had a sender and cable - without the plug - that I found out after driving 30km. Apparently the plug has been superseded and replaced with a round plug, and that is no longer available, so the part is just the sender unit and triple core wire. Returned home to look at how to rebuild or replace the broken section, when it completely fell apart, I put the now free male ends into position in the female plug, then presto, success! Now I'll work out how to make a protective sleeve for the three male ends and that hopefully fully sorts it.

I suspect the sensor assemblies from other parts suppliers (eg Pelican) may also be sans plug, others may know? If they can supply the square plug I'll get one.

Beautiful, albeit frustrating, these fine machines...

SWAUS6
1986 635CSI, alpine white, Getrag CR, Australian delivery
2005 Land Rover Discovery 3, Zambezi silver, TDV6, manual
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hornhospital
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Post by hornhospital »

No plug on the sensor wire? I just got two from Pelican, and both had the rectangular plug attached. Direct fit, plug and play, no fiddling about.
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
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TN_M6
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Post by TN_M6 »

If it is an OEM part it will have all the right plugs. I just replaced a CPS on our 91 M20 and it was exactly the same.

If I had seen your post earlier another bit of diagnostic advice is to look for voltage at the fuel pump fuse to come up while cranking. If it does you have a OK sensor but maybe a bad ignition component. If no spark and no voltage at fule pump fuse you have a bad CPS typically.
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SWAUS6
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Location: Bremer Bay Western Australia

Post by SWAUS6 »

Thanks Ken, good to know Pelican have them as a whole assembly; will place my order. Cheers, Nathan
1986 635CSI, alpine white, Getrag CR, Australian delivery
2005 Land Rover Discovery 3, Zambezi silver, TDV6, manual
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