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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => Project Custom Motobricks => Topic started by: Jon72 on February 18, 2023, 11:57:25 AM

Title: What are the minimum requirements for the ecu to operate
Post by: Jon72 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
Title: Re: What are the minimum requirements for the ecu to operate
Post by: frankenduck on February 18, 2023, 12:13:55 PM
That's a K1100LT, not a K1100RS.

See the bottom of Page 4 here:
http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/kwiring/K1100LT.94on/1994.K1100LT.Wiring.SLP.V2.0.pdf
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 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?
Title: Re: What are the minimum requirements for the ecu to operate
Post by: frankenduck 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.
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 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
Title: Re: What are the minimum requirements for the ecu to operate
Post by: lewisnort 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.
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 on February 23, 2023, 07:28:14 PM
I would greatly appreciate it
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 on February 28, 2023, 07:31:35 AM
The handle bars and rear sets came starting to build
Title: Re: What are the minimum requirements for the ecu to operate
Post by: lewisnort 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.
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 on March 08, 2023, 11:12:33 PM
I also have 2 3button controls my email is jonathandonnelly72@gmail.com
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 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
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 on September 04, 2023, 02:05:28 PM
Ok I have the motogadget wired up and I'm not getting spark any ideas
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Laitch on September 04, 2023, 02:39:26 PM
Is the side stand up?
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 on September 05, 2023, 07:20:43 PM
There's no safety switches hooked up right now they're all bypassed
Title: Re: What are the minimum requirements for the ecu to operate
Post by: rbm 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?
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 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
Title: Re: What are the minimum requirements for the ecu to operate
Post by: The Mighty Gryphon 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.   
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 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
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 on September 11, 2023, 08:32:21 AM
Does the iol pressure switch need to go to the icu
Title: Re: What are the minimum requirements for the ecu to operate
Post by: The Mighty Gryphon 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.
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 on September 11, 2023, 09:00:55 AM
What else would be causing short run time HES?
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Laitch 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?


https://www.youtube.com/watch?v=ohnctG68Ktg (https://www.youtube.com/watch?v=ohnctG68Ktg)
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 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
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Laitch on September 11, 2023, 03:09:19 PM
How about showing the Motronic pin numbers for each wire?
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 on September 11, 2023, 04:16:25 PM
I'm not sure where I would get that information
Title: Re: What are the minimum requirements for the ecu to operate
Post by: daveson on September 11, 2023, 05:39:23 PM
Probably not your problem, I mention this only cause I had the same problem, it would idle for about one minute, then stop. Eventually I replaced the fuel injection computer and it was problem solved. But it was probably just dirty connections. Clean the motronic connections, and other connectors too. There was a thread about this somewhere.
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Laitch on September 11, 2023, 07:17:14 PM
How about showing the Motronic pin numbers for each wire?
I'm not sure where I would get that information
You'd get that information from the drawings at the link frankenduck posted in Reply #1 of this thread.
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 on September 12, 2023, 09:01:08 AM
Alright there was a few problems and I'm getting much closer to a solution the fuel lines were backwards and injector 3 had a loose connection
What cycles the injectors on and off
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Laitch on September 12, 2023, 12:43:11 PM
The Motronic Control Unit under the seat.

Click on the link at the bottom of this post (https://www.motobrick.com/index.php?topic=13441.0) to download an illustrated document to help you understand how your Brick's Motronic engine management system works. This and other BMW training documents are significant contributions to the knowledge base here made by member Volador, who is likely flying somewhere and using the opportunity to find fish to conquer.
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Jon72 on September 12, 2023, 08:30:08 PM
It's running good now
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Laitch on September 12, 2023, 08:57:22 PM
Can you sum up what you did to make it start running good, Jon?
Title: Re: What are the minimum requirements for the ecu to operate
Post by: Freekwillem on October 03, 2023, 08:54:21 AM
Powerbrick posted their wirediagram a few days ago.

(https://i.ibb.co/9Gm27zK/BMW-K1100-RS-1994-MO-UNIT-ULTIMATE-WIRING-DIAGRAM.jpg) (https://ibb.co/9Gm27zK)