1994 K1100 Not starting

[Ingo]

Have you considered jumpering (i.e. "replacing " the relay contact) with a pice if wire at the relay socket? That way you can verify the fuel pump easier.

[Ern]

Hi Guys,

Welcome to Troubleshooting and Life choices Season 1 episode 13 and a quarter,

So quickly recapping where we were up to;
Fuel Pump not starting
No Spark
Dodgy ignition switch...  effectively creating a 260Kg BMW branded paper weight..... and so we move forward....

Ignition switch , as per above, I decided to re-create the ignition switch with a DP-DT (Dual pole, Dual Throw) switch, so effectively the key now only controls the steering lock and nothing else.
I wired up the incoming 12V to both input sides and separated out the Green outgoing 12V signal on one output and the Violet, Gray & Gray/Blue on the other Output. 

and it works!       but still the same, no fuel pump and no spark.

Visually checked all of the fuses again and they still all looked fine, the tell-tale wire on the back of the fuses was intact, so logically they were good, but rather than trusting the visual evidence, and since they are all 15A fuses, I swapped out the accessories fuses for the Fuel pump and Engine Management fuses and low and behold.... I have Fuel pump starting and Spark ...

So basically, I am back to where I started ......     

Some observations though - The spark on the rear coil outputs is significantly less than the front. The front coils will generate a spark that leaps out to the nearest earth (around 15mm or 3/4 inch), the rear coils will only generate a spark when the plug lead is held near them, a distance of about 3-4mm (less than quarter inch)..... so they are working, but not well

Next test will be unplugging all of the injectors and then plugging in one by one and test squirts on cranking....  (Have previously tested the ground signal from all of the plugs back to the ecu pin 27)
I will also do the light test on the injectors

[Ern]

Hi Guys,

So we are back, two updates in one day!....

So welcome back to Troubleshooting and Life choices season 7 episode 9 and 3/64th's

So as per advice for Daveson - I unplugged all of the injectors and did the test light test on all 4 plugs. So with the bike turned off, test light gave no lights when touching the pulse connectors, so all good. Turned the bike on, Cranked over and I get pulsing, but not quite the way I would expect, (i.e. With the starter pushed, the earth light comes on and pulses but not distinctly, its more like a brighter and duller pulse but with a constant level of brightness between pulses)  but again that could just be the test light I'm using. I will try to do another video.

While I was there, I went back and tested both the Brown wire from the HALL Sensor and the Orange wire from the HALL Sensor and they are both providing good strong distinct pulses. Yay for small mercies.

So now I'm starting to question fuel delivery.....i.e. is the fuel pressure regulator stuffed/blocked and even thought the fuel pump is working, its not pushing through enough fuel for the injectors to squirty squirt....

[Scott_]

The FPR on the 1100's are a spring style relief regulator(not vacuum like older bikes). As the pump runs and pressurizes the fuel rail the regulator will open as the pressure reaches the spring set threshold to prevent the pump from "deadheading".
If the spring is weak, then the regulator will bypass too much fuel and not let the rail build pressure for the injectors to work properly.
If the internal diaphragm of the regulator is bad, it won't relieve excess pressure back to the tank return line.
You should be able to hear/see fuel being returned to the tank with the fill cap open while the pump is running. It will spray at the top of the tank forward of the fill cap.

[daveson]

After cranking, if you remove a hose from the fuel rail, does fuel dribble out as if under the influence of gravity, or does it piss out as if under pressure (a bit like air coming out of a tyre, typically at 32 psi, when you remove a valve)

While cranking and using a long screwdriver like a stethoscope against the injectors, can you hear them ticking? They should be.

Turned the bike on, Cranked over and I get pulsing, but not quite the way I would expect, (i.e. With the starter pushed, the earth light comes on and pulses but not distinctly, its more like a brighter and duller pulse but with a constant level of brightness between pulses)

There's something funny going on here. In the videos I posted, the hall sensor signals are mostly on and the computer signals are mostly off, your descriptions sound like the opposite is happening. Your earlier video looks like the injectors were getting a constant earth signal.

I'll be interested to see your videos.

When you're set up for the pulsing earth to injectors test, it only takes a few seconds to also test for pulsing earth to the coils at pin one.

https://youtube.com/shorts/5VrtFtr07-4?si=cPGtqrv9qZeYjOHy

[Ern]

Apologies for the delayed updates but did I mention I'm also in the process of selling my house and relocating...... busy doesn't even touch the sides to describe the last few weeks.....

So anyway welcome back to Season 17, episode 32 of Troubleshooting and Life choices...... and IT'S ALIVE....

Turns out it was fuel lines and fuel filter........    After all the electrical testing, I recalled someone said to check the fuel lines because they have a habit of deconstructing....and yes, opened the tank, tried to check the fuel filter and the fuel line basically started falling apart in my hands. So I've replaced the fuel lines and got a fuel filter off a later K model and it started first kick.......

Going back to the start, I did have a dead injector (coil stuck), a slightly dodgy ignition rotary switch and I managed to blow both fuses 5 & 6 during the troubleshooting phases....
I also think that the test light I have doesn't really work well for showing up the earth pulses on the injectors, so that probably sent us down rabbit holes that didn't need exploring....
but lesson learned, always go back to the basics first....

Thank you to everyone that provided advice , it is deeply appreciated

[daveson]

Good work. It's always a bonus when the solution turns out to be an easy one. At one point it was getting increasingly difficult to assume that the computer was good, but that's behind you now, good one.