1994 K1100 Not starting

[Ern]

Hi All,

First time posting here, so be kind :)

so I have a '94 K1100 LT that is not starting.
Spark doesn't seem to be the problem as it will fire if I spray starter fluid down the bores of the throttle bodies.
Fuel pump definitely starts up when you turn the key.
Injectors spray if manually triggered, but aren't spraying when triggered on the key.

I've been through and tested all the relays and they all seem to be ok. (i.e. I took the fuel pump relay out as it is definitely working and swapped all relays in to that slot and the fuel pump still kicked on with each of the other relays in that spot)

The only real issue I can see is the key barrel seems to now be "loose". i.e. the whole barrel can rock back and forth but I still get dash lights.

The bike was running fine 4 weeks ago and I have drained and swapped in new fuel.

 So what's next in the troubleshooting arsenal??? 

[daveson]

The injectors should be getting constant power and a pulsing earth while cranking. To confirm that they are getting a pulsing earth, connect an LED 12 volt test light (computer safe) clamp to battery positive and probe to one of the injector pins, and then to the other. When connected to the earth pin, the light should flash, as in the video below. (On a K100)

I can't attach the video, low memory?

Type in BMW K100 fuel injector test YouTube, there will be a link to Davidson daveson.
   

[Laitch]

Fuel pump definitely starts up when you turn the key.
Injectors spray if manually triggered, but aren't spraying when triggered on the key.
. . .I took the fuel pump relay out as it is definitely working and swapped all relays in to that slot and the fuel pump still kicked on with each of the other relays in that spot).

Here is the test video daveson describes in his post.

https://www.youtube.com/shorts/2cXY21Zu3Z0

[Ern]

Thanks for the Video link.

Yeh mine looks nothing like the video (but that could just be the test light I got from Repco) . I get a constant light that "kinda" pulses but never goes out (like bright and dull on the pulses but never fully out when cranking)

Also, they are brand new injectors , one of the original injectors was stuffed, so I replaced all 4.

If I pull the fuel rail and injectors out of the block and crank it, I get no fuel squirts.

[daveson]

Thanks Laitch, muchas gracias amigo.

It's the job of the hall sensors to provide a pulsing earth signal to the computer.

Here's a test (again, it's a K100) hopefully I've attached it properly this time.

With the hall sensor test the light only goes off for a split second, unlike the injector test.

It's probably a good idea to clean the computer pins and multi plug with the help of some electrical contact cleaner.

The wiring colours are probably different for a K1100, I'll try to resist making further posts until I've looked at the K1100 wiring diagrams.

[Laitch]

The 1993 K1100's engine management system differs in a few significant ways from the 1994's and all that came afterward. Some countries assigned the model year that the moto was first registered rather than when it was manufactured. Go to realoem, enter the last 7digits of your Brick's VIN and tells us what year comes up.

[Ern]

Hi All,
thanks for all the replies, it is sincerely appreciated.

ok, so I have done the HALL sensor test and I did get a pulsing light when cranking. (yay)
I've sprayed contact cleaner on the ECU pins and the cable end.
I've pulled spark plug leads from the coils and I'm getting good arc's from the coils when cranking,
but still no squirty squirty from the injectors when cranking..... :(

last 7 digits of the VIN are: 0188693

[daveson]

The results are a little different than I was expecting, but let's say for now that you have a pulsing earth to the injectors. The only other thing they need is constant power while cranking.

But first check the fuses, especially those supplied with a red wire. If not blown, check anyway for power to the fuse, and power from the fuse.

If the fuses are good, connect your LED test light clamp to the battery negative post and the probe to the positive of the plug for an injector. The test light should glow constantly while cranking.

[Scott_]

Specifically what brand/type injectors did you install.
The injector pulse is controlled by the same hall sensor signal that triggers the spark.
Check your wiring for any bad/loose/dirty connections.

[Laitch]

Yeh mine looks nothing like the video (but that could just be the test light I got from Repco) . I get a constant light that "kinda" pulses but never goes out (like bright and dull on the pulses but never fully out when cranking)

That dog don't hunt. The pulses should be distinct although momentary. As Scott indicated, there could be wiring problems interfering with correct operation. Below is an image containing a diagram of the Motronic 2.2 fuel injection relay output. The relay can be clicking and the wire running the fuel pump could be okay but the wire that activates fuel injectors—shown at the red arrow—could be faulty somewhere along its length or at its terminals. The Hall sensors are working but the Motronic might not be receiving power to the fuel injectors to complete the process of injection.

When the ignition key is turned On, do you hear the fuel pump start up then stop before the starter button is pressed?

[Ern]

Thanks for the support guys, what a great community !

ok, so I have tested all the fuses and they have all checked out

I've done a video of the bike cranking, with a test light on the injector wiring pins. (Trying the test light on both pins, with the test light connected to battery negative terminal)
From what I understand, it should not look like this.

https://1drv.ms/v/c/e54d88d21dddc7fd/IQA6FS4nPo4CRJNekrruISZdAUjkTsYzA4ZxjJEAQoUUoYc?e=byjMDC

I'm a little suspect that maybe the test light just can't handle the pulses, but maybe that's just a red herring ...... starting question my sanity on all fronts now :)

[daveson]

You can't test the injector earth signal with the test light clamped to the battery earth terminal. Connect the clamp to the battery positive terminal, then with the probe on the injector earth plug, crank, and it should pulse.

The video isn't working well for me but I think it glows constantly at both contacts with the clamp on battery earth? This test result seems to be saying that there is power on both sides of the injector. In that case the computer is failing to provide earth to the injectors. The computer can't provide earth to the injectors if it isn't getting earth. I think there are two earth inputs to the computer, it might be worth checking there.

It would be a good idea to clean up the earth wire connections. You will find a lot of Brown wires connected to the frame under the tank (at least on K100 bricks anyway)

I'm not familiar with K1100 bricks, so this might not be the best next step.

[Scott_]

You will find a lot of Brown wires connected to the frame under the tank (at least on K100 bricks anyway)

I'm not familiar with K1100 bricks, so this might not be the best next step.

On the 1100's the grounds are in the same location, under the tank, bolted where the frame tubes join near the steering head. There should be 2 or 3 brown wires.

Ern, if you still have the old injectors and a VOM meter, measure the coil resistance(in Ohms) and compare the values to the new injectors. You haven't said what injectors you put in, it's remotely possible that the new injector coil "current" requirements for them to properly operate are beyond the capacity of the Motronic control ground sink input.

[Kaos]

Have you tested the injectors themselves (you can do this with a 9v battery and carb cleaner)
Unlikely they're all messed up though. So it could, by the sounds of it, be fuel flow.
In your initial post you've stated you had drained your tank, how have you drained your tank?
Could it be you have a fuel hose blocked, knicked, bend or whatsoever to prevent gas flow to the injectors?
Also have you checked if all hoses inside the tank are whole and connected properly?

[daveson]

From what I understand, it should not look like this.

No, this test result is good. With this test you have proven that the positive pin gets constant power while cranking, which it should.

Your hall sensor test was also good, pulsing while cranking, as it should.

The injectors only need constant power and a pulsing earth to work properly. They're getting constant power, it seems that there is a problem with the pulsing earth.

I'm also starting to wonder if this could be some sort of stupid safety feature denying earth, or something simple like that.

There are two hall sensors, did you also test the other one, at the orange wire? Sometimes they get lazy and can't turn on or off as quickly as they should. The hall sensor wiring colours are sometimes different from the electrical drawings, normally, brown and orange are the output signals.

[Ern]

Hi Guys, so the latest update.

So there a bunch of things that people have asked/suggested so I will try to remember them all.

HALL sensor - Brown wire - tested and looks good
HALL sensor - Orange wire - not tested yet

Fuel - definitely fuel in the fuel rail
Injectors - will squirt if triggered manually
Injectors resistance -  according to the lord almighty, (Google), the injectors should read 15-16ohm. My old injectors read 30 ohm(+/- 2 ohm), the new injectors 50 ohm (+/- 2 ohm).......  ARGH

Earths - I've made up a new earth from the battery to the external earth plug on the ECU. I haven't gone through and tested all earths. (looking forward to that like a poke in the eye with a blunt stick)

and to top it off, the ignition switch now seems to be on the fritz. 2 out of 3 times after I turn the key, I need to press on the bottom of the ignition barrel to get power.....

getting very close to the "parting it out" option and trading back in the registration...

[Past-my-Prime]

Are you certain that the ignition switch hasn't been the root problem all along?

[daveson]

getting very close to the "parting it out" option and trading back in the registration...

Hang in there, it might still be a simple fix.

I wasn't sure if you checked two spark plugs or four. If you had good spark at all four plugs, you can cross the orange wire test off the to-do list. Four plugs sparking means that both hall sensors are working.

To me something doesn't seem to add up. If you're getting constant power and constant earth to the injectors, there should be a constant stream of fuel, instead of no fuel. But let's go with that for a minute. One possible explanation is that there is a short on the earth side. An easy test is to set the test light up as with the pulsing earth test. With the ignition off, the light should be off, if the light is on, there's a short. Then I would remove the injector plug to cylinder one and see if the light is still on. If yes remove plug two as well. If still on remove plug three so that all injectors are unplugged, and check if the light is on. With all injectors unplugged, check also for a pulsing earth while cranking.

[Scott_]

As I look at the video in post #10, I suspect that the internal ground path from the injector sink input to the earth inputs of the ECU is broken.
The test light is lighting on both injector connections when only 1 plug is disconnected, which would make sense as the plugs are wired in parallel to all 4 injectors.
As Daveson suggests, test the injector leads with all 4 injectors disconnected.
You have already shown that you have the +12 when cranking so you don't need to test that again.
To test the ground, as suggested, connect the test light flying lead to the battery positive connector, When cranking the light should NOT be lit on the "hot" wire(green/white), and the light should "pulse" on the ECU ground sink line(yellow/grey).
If it doesn't pulse on the yellow/grey, you have other issues.
If my schematics are correct the yellow/grey line should terminate at the ECU terminal #27. You could check wire continuity from #27 to the injector plug to verify that it's not damaged or that the splice is still intact.

There should be 3 battery ground 'inputs' to the ECU. Terminals 13, 21, and 26 are all connected to battery ground.

Ern, when you said earlier that one of the original injectors was "stuffed", what did you mean by that... fuel plugged? coil shorted?  What wasn't working about it.

I attached a page from the BMW factory motronic testing manual that might help.

[Ern]

 Thanks for the continued support guys, very much appreciated.

So 1 step forward, 3 steps back......

So I've now tested and can confirm - ECU cable pins 13, 21 & 26 are all connected to ground with the correct spec resistance (all 3 showed as 22 exactly the same as the page from the manual) (Thanks Scott for sharing that).

I can also confirm that I have continuity between all of the injector cables and pin 27 on the ECU cable.

BUT....that's where all of the progress halted and has now gone down hill. I now no longer have any spark and the fuel pump does not start up either ......so its like the kill switch has been triggered !?!

The bike still cranks, still has instrument lights ....checked all the fuses, they are still all good. I'll check up on how to test relays.

Tomorrow will be removing the ignition switch and testing it, will let you know how that goes.

Has anyone built an ignition switch bypass before , I imagine you just take power from pin 2, put it through a switch and on the other side give power to pins 3,6,7,and 8. ?

(yeh I'm getting desperate)

(almost forgot, for Scott, the dead injector has a stuck coil so that's why I needed to replace)

[Laitch]

Tomorrow will be removing the ignition switch and testing it, will let you know how that goes.

[daveson]

Tomorrow will be removing the ignition switch and testing it, will let you know how that goes.

 

[Ern]

 

Welcome back everyone to the ongoing saga of electrical gremlins.....in today's episode we will be relay testing, continuity testing, doing an ignition switch removal, and questioning your life choices.....

So the issue with the ignition switch is -
1. Someone has been in here before me and
2. To get the dash lights (or anything else) to power up, you need to press on the plastic cap at the bottom of the switch. If you don't apply pressure, its dead
as a dodo. After you have applied pressure, it will stay "lit up" until you turn it off again. Lets just call this status "pretend on".....

So after achieving "Pretend on" I tested power at the orange connector under the tank.
Red - (12V from the battery) - Check
Green - (12V from the Switch) - Check             
Gray/Blue - (12V from the Switch) - Check       
Gray - (12V from Switch) - Check
Violet - (12V from Switch ) - Check

But still No Fuel pump powering up and No Spark.....so I figure "Pretend on" is like a ladyboy in thailand, looks good on the surface but is really just being a dick

So lets move on to the relays....
Pull the Fuel pump relay - check the resistance - shows 100 Ohm internal resistance between pins 85 & 86... so within spec.
Remove the Horn relay, plug the fuel pump relay into the horn relay slot and Boom - Horn works..... so assumption is that the Fuel pump relay is good.
Check the Fuel pump relay socket with ignition on - 12V showing up on the Pin 30 socket - So power is making it to the relay, and the relay is good, but the pump doesn't get power - Going to need to do some more testing from Fuel pump relay onwards - that will be a future episode, so stay tuned

So on to Miss "Pretend on" ignition switch...
So I found an excellent article on the K1100 ignition switch here: https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/4vignsw.forklock/4vignsw.forklock.htm
I drilled the security bolts in about 3mm and then reversed the drill, luckily the drill bit caught the bolt so they basically unscrewed using the drill bit on reverse.... yay for small wins
Found the grub screw, some Neanderthal had definitely been there before me as the driver slot was already flogged out, but finally managed to get the screw undone and then promptly screwed it out to far and away she went bouncing across the floor....... thank god for magnets.... there was no way I would have found the little f*cker with my eyesight... so crisis averted.

So pulled apart the switch, tested continuity from the plug through to the switch, every thing fine on the wiring side, but yes, unless the body of the switch is pressed down firmly, the switch doesn't make contact with the pins..... so I am up for a new switch  (BMW Part # 61322305292).... which after some googling, seems to be almost impossible to get hold of .... the only one I did find is $200Euro plus freight from Germany to Australia......UGH 

So if any of you guys have spares, please let me know !

In the meantime, I'm going to dissect the current cable and make up 2 switches, one for Red to Green and one for Red to Violet, Gray & Gray/Blue

and then contemplate searching for earthing problems on the Fuel system.....   To infinity and beyond.....   

[Past-my-Prime]

Perseverance will win the day. When you get this running again, you'll have earned it.

The opposite of ADHD is AEHD (attention excess hyperactive disorder) which is sort of the reverse of the coin, and shared by many. It can be a helpful adaptation and summarizes many of the successes I've enjoyed in my life.

Since we're in the northern hemisphere where it is now the middle of winter, I'll be observing your diagnostic course with interest. At least until I have a heated workshop, myself.

[daveson]

I tell myself not to post on K1100 threads because I'm not familiar with them, but I've tumbled in, once again. The Clymer drawings I'm looking at don't number the relay pins and don't show a circuit for the violet wire, but that won't stop me from taking a punt either, even though it should.

Your new problem looks to me like no power to the pump and no power to the coils. The first thing I think they have in common is power from the ignition switch. You have power from the switch to the plug, goodo, but is there power from the plug? I'm referring to the green wire. I think so not, but, if yes, keep probing back to the coil unit you find where the power loss is.

Once the new problem is fixed, repeat the pulsing earth test while cranking, with the injectors unplugged. If there is a pulsing earth signal, that hopefully means that there is nothing wrong with your bike, and simply the injectors aren't suitable.

Question; attention excess hyperactivity disorder, that sounds pretty good, where can I get some of that?