Author Topic: What are the minimum requirements for the ecu to operate  (Read 1726 times)

Offline Jon72

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What are the minimum requirements for the ecu to operate
« on: February 18, 2023, 11:57:25 AM »
I bought a 1995 k1100lt and am in the process of building a cafe racer I need to know what I need to keep in the bike for it to run I will be using a m-unit blue for lighting and controls I'm just not sure about what inputs the ucu needs
  • Texas
  • 1995 k1100rs

Offline frankenduck

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Once I had a Collie pup. Dug a hole and covered him up. Now I sit there by the hour. Waiting for a Collie-flower.
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Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #2 on: February 18, 2023, 12:41:22 PM »
So if I supply power to the 15 pin and power the fuel pump it should run?
  • Texas
  • 1995 k1100rs

Offline frankenduck

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Re: What are the minimum requirements for the ecu to operate
« Reply #3 on: February 18, 2023, 01:55:46 PM »
The brown/blue wire from the side stand switch needs to be grounded to that the Motronic relay sends power to Pin 33 of the Motronic.
Once I had a Collie pup. Dug a hole and covered him up. Now I sit there by the hour. Waiting for a Collie-flower.
New to K bikes? Click here.
K Bike Maintenance & Mods: Click here.
Buy parts here.

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #4 on: February 18, 2023, 03:24:23 PM »
Will I need power supplied to the green and green black going to the coils and injectors
  • Texas
  • 1995 k1100rs

Offline lewisnort

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Re: What are the minimum requirements for the ecu to operate
« Reply #5 on: February 21, 2023, 09:16:13 AM »
Hi Jon, I’m also doing an LT (1998) using an munit blue.
I have a wiring diagram made up where I’m only keeping the engine management loom, i.e. motronic plug to the sensors and injectors and such. The rest will be hand made.
If it works and I can get it running soon I’ll let you know and I can send it to you if you want.
  • UK
  • 1998 K1100 LT

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #6 on: February 23, 2023, 07:28:14 PM »
I would greatly appreciate it
  • Texas
  • 1995 k1100rs

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #7 on: February 28, 2023, 07:31:35 AM »
The handle bars and rear sets came starting to build
  • Texas
  • 1995 k1100rs

Offline lewisnort

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Re: What are the minimum requirements for the ecu to operate
« Reply #8 on: March 07, 2023, 04:37:47 AM »
What bars are you using and which bar controls are you planning to use? I’m going to run clip ons and have 2 3 button motogadget controls. It’s my first time working on a bike in this way so I’m not sure where I would get a throttle from since the original has buttons integrated. Do you have an email address I can send the wiring diagrams to? Sorry not had chance to test it yet, way too freezing in the uk for me at the moment.
  • UK
  • 1998 K1100 LT

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #9 on: March 08, 2023, 11:12:33 PM »
I also have 2 3button controls my email is jonathandonnelly72@gmail.com
  • Texas
  • 1995 k1100rs

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #10 on: March 08, 2023, 11:14:35 PM »
I'll be running just a basic cable throttle and the handlebars I got are from cafe4racer.eu they're bolt on as well
  • Texas
  • 1995 k1100rs

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #11 on: September 04, 2023, 02:05:28 PM »
Ok I have the motogadget wired up and I'm not getting spark any ideas
  • Texas
  • 1995 k1100rs

Offline Laitch

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Re: What are the minimum requirements for the ecu to operate
« Reply #12 on: September 04, 2023, 02:39:26 PM »
Is the side stand up?
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #13 on: September 05, 2023, 07:20:43 PM »
There's no safety switches hooked up right now they're all bypassed
  • Texas
  • 1995 k1100rs

Offline rbm

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Re: What are the minimum requirements for the ecu to operate
« Reply #14 on: September 05, 2023, 10:26:31 PM »
It's really hard to give you advice since we have no clue what you've kept and what you've discarded from the original loom in your effort to switch to the Motogadget.

The spark comes from the ICU.  You'll need switched power, ground, HES inputs, and start button signal.  Have you got those?
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #15 on: September 11, 2023, 04:58:16 AM »
I think I have all of those I can get it to fire and stay running for under a minute then it dies out I'm thinking oil pressure switch or coolant temp since those aren't hooked up I don't know where to run them to
  • Texas
  • 1995 k1100rs

Offline The Mighty Gryphon

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Re: What are the minimum requirements for the ecu to operate
« Reply #16 on: September 11, 2023, 07:22:56 AM »
Are you absolutely sure the fuel pump isn't dropping out when you release the start button.  I say this because the fuel system holds enough fuel to run the engine for about a minute at idle without the pump.

You might want to get a fuel pressure gauge to see what the the pressure is doing in the rail after the engine starts.  I think you can borrow or rent one at AutoZone.   
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #17 on: September 11, 2023, 08:29:23 AM »
I just replaced the fuel pump and cut the wire and am holding it on the battery to guarantee the pump is running
  • Texas
  • 1995 k1100rs

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #18 on: September 11, 2023, 08:32:21 AM »
Does the iol pressure switch need to go to the icu
  • Texas
  • 1995 k1100rs

Offline The Mighty Gryphon

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Re: What are the minimum requirements for the ecu to operate
« Reply #19 on: September 11, 2023, 08:34:19 AM »
The oil pressure switch just lights up the idiot light on the cluster to let you know there is no pressure.  It has nothing to do with the operation of the engine.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #20 on: September 11, 2023, 09:00:55 AM »
What else would be causing short run time HES?
  • Texas
  • 1995 k1100rs

Offline Laitch

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Re: What are the minimum requirements for the ecu to operate
« Reply #21 on: September 11, 2023, 12:54:20 PM »
What might be helpful is for you to post clearly legible diagrams, with wire color labels, sufficiently large enough to show all wiring connections—and their sources—for input and output at the Motogadget instrument and M-unit. Was this video your inspiration?


  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.

Offline Jon72

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Re: What are the minimum requirements for the ecu to operate
« Reply #22 on: September 11, 2023, 01:59:17 PM »
This is how it's wired except I don't have a dash the fan isn't hooked up yet and the fuel pump is direct and the hand controls are wired using a mo button
  • Texas
  • 1995 k1100rs

Offline Laitch

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Re: What are the minimum requirements for the ecu to operate
« Reply #23 on: September 11, 2023, 03:09:19 PM »
How about showing the Motronic pin numbers for each wire?
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.

Offline Jon72

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  • Posts: 17
Re: What are the minimum requirements for the ecu to operate
« Reply #24 on: September 11, 2023, 04:16:25 PM »
I'm not sure where I would get that information
  • Texas
  • 1995 k1100rs

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