Ignition / Electrical problem - K-Bikes.com - Excellence in Motion
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post #1 of 4 (permalink) Old Sep 25th, 2008, 5:49 am Thread Starter
Join Date: Sep 2008
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Question Ignition / Electrical problem

Good morning. I have a 1991 K100LT. Earlier this year the bike started to backfire a lot and then whilst out riding it just died and I had problems starting it. I did get it home but have not been able to start it since. When you turn on the igintion, it sounds as though the fuel pump is continually operating. I thought it might be a problem with the fuel rail or injectors but subsequent advice from a BMW service agent stated it was the ignition control pack. They quoted a part price almost as much as the bike is worth so a new one is out of the question. They couldn't help with a second hand part.

Having looked online, all I seem to find info about is an "electronic control unit" (ECU) not an "ignition control unit" (ICU). My ECU is under the seat but I have seen other posts on this forum that indicate an ICU under the tank. Certainly when I disconnect the ECU I still get the same symptom with the fuel pump etc.

I would be grateful for any information about this problem. Thanks.
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post #2 of 4 (permalink) Old Sep 25th, 2008, 10:45 am
Join Date: Jul 2004
Location: , SoCal., USA
Posts: 1,507
Use the search function and type in "Hall effect sensor". There is a lot of information on your problem.

Bruce C
'04 K1200RS Capri Blue(totaled)
2008 Triumph Sprint ST
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post #3 of 4 (permalink) Old Sep 29th, 2008, 3:55 pm Thread Starter
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Thank you for the info. Although I cannot start the bike, when you turn on the ignition, the tachometer seems to come to life intermittently and revs up to a 1000 rpm as well as the fuel pump starting and stopping. It is certainly trying to send a spark as it has a very weak backfire even without the engine running. Tried a couple of simple remedies with relays but no luck.

Have now taken off the tank and removed the ignition control pack. On internal inspection it seems as though there may be a short within the pack so guess the BMW service agent was right. I have managed to find a used part from the UK so here's hoping.

If that doesn't do the trick then I will investigate the Hall effect sensor further.

Thanks again.
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post #4 of 4 (permalink) Old Oct 4th, 2008, 12:36 pm Thread Starter
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All Fixed

I have managed to get a used ignition control unit from England and fitted it today. That together with a new set of plugs has resolved the problem and it is now running again. Thank you for the helpful suggestion.
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