BMW K bikes (Bricks)

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1Back to top Go down   Another Hall sensor question... Empty Another Hall sensor question... Mon Aug 10, 2015 5:02 pm

Dai

Dai
Life time member
Life time member
I've been working on a K100LT and have run into a now non-firing situation. At some time in the past a PO has seriously bodged the shielded cable that goes from the ignition module to the hall sensor assembly (bodged as in cut the outer sheathing off, removed the shielding and then wrapped the shielding spiral-wise back along the length of the cable...). This looked like a simple-enough repair as in cut the original bodged cable out from the ignition module to the black plug, then using the correct crimp pins at the IM end and the black plug end, fit a new section of OEM shielded cable. So far, so simple.

Well, maybe. The bike won't start. Continuity from socket to plug is correct. There is also continuity and power down to the HE sensors. Fuel is being pumped (ask my jeans how I know...). The spark plugs are dry, suggesting that there is no signal from the ignition module to the FICU.

Using an analogue multimeter I checked the brown (signal) to red (positive) and cranked the engine. The meter flicked about 1.25v as expected. The same test on the orange (other signal) left the meter indicating infinity - no movement at all. That suggests that just one Hall sensor has gone awol. Reasonable assumption but... if just one HE has gone awol, why am I not getting fuel through to the engine and sparks on two out of the four plugs?

Question asked by Puzzled of Tunbridge Wells.


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1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

2Back to top Go down   Another Hall sensor question... Empty Re: Another Hall sensor question... Mon Aug 10, 2015 5:48 pm

charlie99

charlie99
VIP
VIP
just a thought without checking ....but could the hall effects become reversed as in top - bottom going into the ecu at the wrong connection at that plug and time in relation to piston timing ?  I have a feeling that the timing is generated by one of the hall effects with additional information from the second


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OAnother Hall sensor question... Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

3Back to top Go down   Another Hall sensor question... Empty Re: Another Hall sensor question... Mon Aug 10, 2015 6:28 pm

Dai

Dai
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Life time member
Possible... I can't check directly because the bike is now about 200 miles and a big splash away from here. I'll pull the cover off mine and look tomorrow - not so daft because I have a good mental picture of the plate on the LT.

[Edit] It's not that. I just had the sense to check the manual!


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

4Back to top Go down   Another Hall sensor question... Empty Re: Another Hall sensor question... Mon Aug 10, 2015 8:20 pm

RicK G

RicK G
admin
admin
if just one HE has gone awol, why am I not getting fuel through to the engine and sparks on two out of the four plugs?

Because the 2-3 sensor controls the fuel injection timing. All the 1-4 sensor does is fire the plugs.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

5Back to top Go down   Another Hall sensor question... Empty Re: Another Hall sensor question... Mon Aug 10, 2015 8:38 pm

Dai

Dai
Life time member
Life time member
@RicK G wrote:Because the 2-3 sensor controls the fuel injection timing. All the 1-4 sensor does is fire the plugs.
Something is sort-of making sense here but my ignorance is still showing. Taken at face value, this suggests that (depending on which HES has failed), you'd either get sparks or you'd get wet plugs. So, trying to add some logic to this, if the 2-3 HES controls the fuel injection, would a faulty 2-3 HES prevent the 1-4 HES from actually firing the plugs (as in some logic inside the ignition module)?


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

6Back to top Go down   Another Hall sensor question... Empty Re: Another Hall sensor question... Mon Aug 10, 2015 8:52 pm

RicK G

RicK G
admin
admin
From what I can work out they should still fire but then again we are talking about a BMW here Laughing


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

7Back to top Go down   Another Hall sensor question... Empty Re: Another Hall sensor question... Tue Aug 11, 2015 6:00 am

Dai

Dai
Life time member
Life time member
Thanks Rick. We've got a s/h HES plate on the way from Motorworks and I have a spare ICU and FICU in the cupboard, just in case.


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

8Back to top Go down   Another Hall sensor question... Empty Re: Another Hall sensor question... Wed Aug 12, 2015 9:48 pm

Holister

Holister
Life time member
Life time member
@Dai wrote:....
Using an analogue multimeter I checked the brown (signal) to red (positive) and cranked the engine. The meter flicked about 1.25v as expected. The same test on the orange (other signal) left the meter indicating infinity - no movement at all. That suggests that just one Hall sensor has gone awol. Reasonable assumption but... if just one HE has gone awol, why am I not getting fuel through to the engine and sparks on two out of the four plugs?

Question asked by Puzzled of Tunbridge Wells.
Dear Puzzled
The info I've read on the Jetronic says that it receives signals from both hall sensors, 4 timing signals per 720° (1 engine cycle) and then divides the signals by 2 and shapes them into 2 pulses for the injectors.

If one HES fails I would suspect the FICU would not have the required number of timing signals to form any injection pulse so no fuel to the injectors. You'd also get only one coil firing.



Last edited by Kaptain Holister on Thu Aug 13, 2015 1:31 am; edited 2 times in total (Reason for editing : last sentence did not read correctly)


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1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  Another Hall sensor question... Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

9Back to top Go down   Another Hall sensor question... Empty Re: Another Hall sensor question... Thu Aug 13, 2015 6:02 am

Dai

Dai
Life time member
Life time member
Do you know what I really hate? It's when you do a really simple job and something related to that job (but not part of it and has not been touched) decides to give you the finger for no apparent reason. What was it that RickG said?

@RicK G wrote:(...) but then again we are talking about a BMW here Laughing

I'm now trying to fix this problem by remote control from about 250 miles away - I'll keep you informed.


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

10Back to top Go down   Another Hall sensor question... Empty Re: Another Hall sensor question... Fri Aug 14, 2015 9:16 am

Dai

Dai
Life time member
Life time member
Just had a phonecall confirming it was the HES and the bike is running again bounce . The owner may just be appearing here at some point.


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

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