Help! Anyone got any sensors?

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Dan Stevens View Drop Down

Newbie

Joined: 11-May-2004
Location: United Kingdom
Status: Offline
Points: 36

Topic: Help! Anyone got any sensors?
Posted: 31-March-2006 at 09:04

Hello all,
My '83 635 auto won't start, and I have a feeling it's the crank/speed
sensors - the ones that slot into the side of the bellhousing. I need a
good set to test this theory with - so does anyone have a used pair I
could buy?
If you're in striking distance of London that would be even better,
because then I could come and get them as soon as possible! The car's
been immobile for too long�
Email me (daniel.stevens@haynet.com) or call/text 07866 688 783.
Thanks a lot
Dan

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phb10186

Really Senior Member I

Joined: 18-April-2005
Location: North London
Status: Offline
Points: 331

Posted: 31-March-2006 at 19:04

Dan: I had a non -start issue with my six for ages... I thought it was the sensors for ages, have a look at my post 'Non-start the saga continues' on this forum. Please read that as it tells you the relevant resistances for those sensors (I think). If the resistances are OK, then the sensors are OK.

There is a web hosted haynes manual with that information, but I cant remember the link to it

If someone could please post where the sensor resistances from the online 5 series haynes manual are, this would be a huge help to Dan. (Or if you know them off by heart!)

Bear in mind an older sensor will show a higher resistance to a new one - but the readings will speak for themselves when you test them.

1985 635 CSI with Style 134's
1998 Z3 2.8i

Dan Stevens View Drop Down

Newbie

Joined: 11-May-2004
Location: United Kingdom
Status: Offline
Points: 36

Posted: 03-April-2006 at 08:30

Thanks for that. I've tested the sensors as per Haynes (one gives no
readings at all, the other gives a reading for one of the tests and nothing
for the other), removed them, cleaned them and put them back.
I've also heard that this test doesn't mean very much and can't be relied
on - what do you think?
Apparantley the only way to really be sure is to swap them for a pair of
known good ones.
Cheers
Dan

phb10186

Really Senior Member I

Joined: 18-April-2005
Location: North London
Status: Offline
Points: 331

Posted: 03-April-2006 at 09:05

The sensors are essentially a magnet that picks up a signal from teeth on the flywheel, and then sends a signal to the ECU. They are both the same part from BMW, so that means that they are identical to one another.

From my pains, I have ascertained that one of the sensors is the Top dead centre position sensor, and triggers the ECU to start its job, and the car to start. If this sensor is gone the car will never start.

The other is used for the RPM part of the speedo - I think. Since they are identical parts, they should test the same.

A new set is about �90 from BMW, but you can get them from other places. If you can test them to ensure that they work, then I think thats all you need.

Also, I know that the position of these sensors might vary.

Drew540 allerted me to the possible horror of the TDC pin falling off the flywheel - and if thats the case even renewing the TDC sensors will not help. Also that mighe well be a gearbox out job, unless someone very skilled indeed can wels a new wooth on at the correct place on the flywheel.

Read 'NON-start - The saga continues', it contains all the information that you will be repeated for you.

Make sure all your relays work, and that any work that has been done on the car has not resulted in a disconnected plug somewhere.

I did replace my sensors, so if you want to borrow my set, then you can, just PM me (NW London) - although I am pretty sure one of them has had it.

I think that if you can get the resistances checked, and they look OK, then they are going to be OK - as I said, all they are is a magnet.

1985 635 CSI with Style 134's
1998 Z3 2.8i

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
Dan Stevens Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 11-May-2004 Location: United Kingdom Status: Offline Points: 36	Topic: Help! Anyone got any sensors? Posted: 31-March-2006 at 09:04
	Hello all, My '83 635 auto won't start, and I have a feeling it's the crank/speed sensors - the ones that slot into the side of the bellhousing. I need a good set to test this theory with - so does anyone have a used pair I could buy? If you're in striking distance of London that would be even better, because then I could come and get them as soon as possible! The car's been immobile for too long� Email me (daniel.stevens@haynet.com) or call/text 07866 688 783. Thanks a lot Dan

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phb10186 Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member I Joined: 18-April-2005 Location: North London Status: Offline Points: 331	Posted: 31-March-2006 at 19:04
	Dan: I had a non -start issue with my six for ages... I thought it was the sensors for ages, have a look at my post 'Non-start the saga continues' on this forum. Please read that as it tells you the relevant resistances for those sensors (I think). If the resistances are OK, then the sensors are OK. There is a web hosted haynes manual with that information, but I cant remember the link to it If someone could please post where the sensor resistances from the online 5 series haynes manual are, this would be a huge help to Dan. (Or if you know them off by heart!) Bear in mind an older sensor will show a higher resistance to a new one - but the readings will speak for themselves when you test them.
	1985 635 CSI with Style 134's 1998 Z3 2.8i

Dan Stevens Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 11-May-2004 Location: United Kingdom Status: Offline Points: 36	Posted: 03-April-2006 at 08:30
	Thanks for that. I've tested the sensors as per Haynes (one gives no readings at all, the other gives a reading for one of the tests and nothing for the other), removed them, cleaned them and put them back. I've also heard that this test doesn't mean very much and can't be relied on - what do you think? Apparantley the only way to really be sure is to swap them for a pair of known good ones. Cheers Dan

phb10186 Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member I Joined: 18-April-2005 Location: North London Status: Offline Points: 331	Posted: 03-April-2006 at 09:05
	The sensors are essentially a magnet that picks up a signal from teeth on the flywheel, and then sends a signal to the ECU. They are both the same part from BMW, so that means that they are identical to one another. From my pains, I have ascertained that one of the sensors is the Top dead centre position sensor, and triggers the ECU to start its job, and the car to start. If this sensor is gone the car will never start. The other is used for the RPM part of the speedo - I think. Since they are identical parts, they should test the same. A new set is about �90 from BMW, but you can get them from other places. If you can test them to ensure that they work, then I think thats all you need. Also, I know that the position of these sensors might vary. Drew540 allerted me to the possible horror of the TDC pin falling off the flywheel - and if thats the case even renewing the TDC sensors will not help. Also that mighe well be a gearbox out job, unless someone very skilled indeed can wels a new wooth on at the correct place on the flywheel. Read 'NON-start - The saga continues', it contains all the information that you will be repeated for you. Make sure all your relays work, and that any work that has been done on the car has not resulted in a disconnected plug somewhere. I did replace my sensors, so if you want to borrow my set, then you can, just PM me (NW London) - although I am pretty sure one of them has had it. I think that if you can get the resistances checked, and they look OK, then they are going to be OK - as I said, all they are is a magnet.
	1985 635 CSI with Style 134's 1998 Z3 2.8i