Hall Sensor?

[Possu]

What are the symptoms of a dodgy Hall Sensor?

My 48,000+ mile 2001 1150GS has an intermittent fault whereby it occassionally fails to turn over when the starter button is pressed. I can hear the fuel pump priming when the kill switch is in the RUN position. When the bike does not start, there's no noise from the bike at all i.e. no clicking starter relays or solenoids similar to when the battery is flat. When the bike does fire up, it always does so immediately, normally never requiring any use of the fast idle lever unless it's exceptionally cold. If I bump start it, it runs perfectly.

I've replaced the right hand switchgear, starter relay & starter motor with exactly the same intermittent symptoms. Sometimes the bike is fine for a week and then it just lets me down. I can see no pattern to problem i.e. only when it's hot, cold or raining? Sometimes it starts within a minute or so, other times, it's hours.

It's fitted with a Datatool alarm, I've just emailed them asking for their opinion and asking how easy it is to disconnect the alarm. I know enough not to just rip it off the bike. Wondering if the immobiliser function is not being disarmed when I press the alarm fob - is this possible or likely?

Could the Hall Sensor be the culprit? Is it wired in to the ignition only or is it wired in to the starting system also? The fact that it's intermittent makes it a PITA to trace.

All sensible help & ideas appreciated.

Thanks in advance.

Steve

 

[Timolgra]

I won't attempt to diagnose your bike right now, but if you need a 'new' sensor, I bought a 2nd hand complete unit to have as a spare which includes the mounting plate from James Sherlock (01769 574350)

BUT I would check your side stand switch first

 

[Sergeant Pluck]

Check your battery connections - I had symptoms very similar to yours a while back; scratched my head for ages before finally cleaning up and re-tightening the poles, which fixed the problem. Worth a try

 

[Micky]

If it fails to turn over on the starter then it's not the Hall sensor! When that goes, as far as I understand, you won't get the fuel pump priming.... so's you can't keep turning the engine over and over, and with no spark, fill the exhaust with big bang mixture

 

[Den]

The hall sensor will not prevent the engine from turning on the starter motor. Its only for the ignition timing

 

[graham2400]

Hall Sensor

Follow the link for a write up on the hall sensor and it's repair.

www.ebbo.org/2av54.php


Regards,

Graham

 

[Possu]

Forgot to mention this in my original post:

I've disconnected the Clutch Interlock switch in the past, problem persisted when disconnected & bridged and then reconnected?

Disconnected the Side Stand switch from the loom. Didn't bridge it as there are three wires, didn't which to bridge and also it's wired in to the Motronic. At one point it decided to turn over but wouldn't start die to the switch being disconnected.

Already cleaned & retightened the battery terminals, will do so again though.

On ething that may point towards the alarm is that when the bike's operating fine, the indicators flash twice on being armed and once when disarmed. When in "not turning over" mode, the alarm beeps twice on arm & once on disarm as normal but the indicators fail to flash as usual - only noticed this arlier this evening. When working, all indicators & hazard lights work normally?

Thanks for the replies, keep 'em coming.

 

[Pressurized]

Those who say a failed Hall sensor won't stop the bike turning over are correct.

When one (or both) sensors failed on my R1100 GS, the engine would tick over at lowered revs (c. 1000 rpm) and any attempt to increase the revs would stall it. The fault could not be diagnosed on the BMW test computer at the time (1998-ish).

 

[Jimb]

Alarm

My mates Fireblade suffered this same problem and it was the alarm, exactly the same symptoms, the alarm usually interupts the starter relay but the ignition will turn on, the only action is to de-install the alarm. Not as difficult as it sounds, you need a testmeter to trace out the wiring and then bridge the circuits.
This is the risk with immobilisers they can immobilise you when you least expect it.

 

[BBC1]

BBC1

This may help. To take the starter circuit 'out' of the alarm, look for the black yellow wire from the bikes loom being interrupted and looped into the alarm loom. This normally happens on top of the A frame, or in the electrics box under the seat.

 

[Possu]

Problem fixed, dodgy alarm at fault, starting circuit was still immobilised.

Thanks for the replies.

 

[Vern]

Doh! I just read all through that,and I get to the bottom,and you've fixed it.Please can you reinstate the fault,so I can tell you that it's more than likely your alarm that's causing the problem,and everyone will think I know what I'm talking about

 

[Rob Farmer]

It's ok Vern - We know you don't

 

[Possu]

Problem reinstated so that Vern can come to Oxford immediately & carry out a top repair at his expense. Please note that I need to leave for work at 0745 tomorrow morning.