Need electrical help on a 1989 BMW k100 Rs

Diagrams can be found here

I'm not familiar with these bikes but I can help decipher the wiring diagram.

Focusing on the main issue, the fuel pump gets it's power from the fuel injection relay. It should have power out with ignition on both (2x) Green and Red wires. The smaller one those 2 feeds the pump fuse. If power is missing, check for ground with key on from Ignition control module. This will be the Yellow and Brown wire at the same relay. If that's missing could be something to do with OE cluster not being there.. but start with the above


Just to cover the other 2 wires at the relay. Big red one should have power at all times, and the last one (green and yellow) should have power with ignition on.

Edit: if I'm looking at the right diagram

It's not likely to be your problem, but on a K75 I had something very strange happening with the computer power. The ground for the computer was offset by +5V from the battery ground (resulting in a very unhappy computer as it was only getting 7V). An unhappy computer could cause many symptoms and it is easy to check the power there.

Alex,

Neutral is determined from a transmission gear position indicator (TGPI) and needs to be detected using a special circuit. You removed that circuit by replacing the OEM cluster with an aftermarket gauge. That means you have to either build such a circuit using three relays (http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/gpi/gpi.htm ) or steal the TGPI circuit out of the OEM cluster or use a special circuit like what I manufacture and sell ( http://www.k100-forum.com/t4708-gear-indicator-for-aftermarket-speedometer-and-other-circuits ) or that is sold by Maru ( http://www.maru-labs.com ).

Without neutral, the start relay will not engage. If the start relay does not engage, then the starter will not work and the engine will not turn over. If the engine does not turn over, then the hall sensor will not send the signals to the ICU. If the ICU does not detect the hall sensor signals, it will not turn on the FI relay and the fuel pump will not get power. Try this: Pull in the clutch and press the starter button. The engine should turn over. You should be able to hear the fuel pump run for 1.5 seconds AFTER you release the starter button. This will prove that the circuitry in the bike is operating. You will need to get Neutral working in order to start the engine without pulling in the clutch.

If things are still not working for you after this, then refer to Bert's troubleshooting page ( http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm ) or fire off a PM to me and I'll try to help.

The oil pressure switch will be grounded with too little oil pressure, like with the engine cold. Have you hooked up the pressure switch to an LED indicator on your gauge that lights when its input goes low?

Thank you all for your input. This morning I worked at this problem and with the help of some good people we reached the same conclusion that by removing the OEM cluster the bike will not start. ROBERT I am very interested in that special circuit that you are building so how can I get in touch with you?

Tomorrow I will try to reconnect the OEM cluster, and to answer the oil pressure question , the new gauge doesn`t have an indicator so I added one myself , and id does not light up.

My phone # is 519-574-0517

Thank you again

Alex

Test the oil pressure switch. It is located in the oil / water pump, on the left side and has a single brown wire attached to it. It should normally be closed and register continuity to ground when the engine is stopped. The wire winds its way through the hall sensor area and up through the front cover, emerging under the tank on the right side. Normally, you connect up a 12V LED indicator the anode of which is connected to a source of switched +12V such as on Pin 6 (Green/Black) and the cathode of which is connected to the switch. With the engine off and the switch closed, the LED should light. With the engine running and the oil pressure normal, the switch will open and the LED will extinguish.

If you want to read about the board I produce, below is the link to the installation manual on my Google Drive:

https://drive.google.com/drive/folders/0B3UPbNZRyr1rd2JrNGI0UHBsOTA

I managed to reconnect the OEM cluster . Bike started up after I replaced a couple of bad conectors and it is all ok.
Thank you again for your help . I want to purchase the board you produce with the installation guide and all other information.
How can I do that ? Let me know and I will come and see you and buy one from you.

Have a great weekend.

Alex