K75 Starting Issues.. Fuel Pump priming?

[bluebossa]

Howdy,


Recently commissioned K75 was running fine, now won't start.


Sparks present
Engine Turns Over
Splutters, coughs and backfires
Battery Charged 13.2V
Took the plugs out - which seemed to be wet and cleaned them


Took the Tank off to clean out the fuel pump and also found a suspect connector which was replaced.


When the ignition key is turned on the Fuel pump DOES NOT whirr - which I am used too on my other K75...


So I took the pump out of the tank and Wired the fuel pump direct to a battery and it pumps.
When cranking with the fuel pipe from the tank disconnected, fuel pumps into a Can...


Do all K75s have to have that Fuel pump priming noise when the key is turned?
Mine doesn't do this so what would that point too?
I'm thinking something is wrong with the Pump of Control system?


Any ideas gratefully received.

[Scott_]

From what I have read of the k75's, they do not prime with key on. Only when starter button is pressed.

[Laitch]

When the ignition key is turned on the Fuel pump DOES NOT whirr - which I am used too on my other K75...  Mine doesn't do this so what would that point too?

It doesn't point to anything yet, as far as I'm concerned.

My K75 does not whir when the key is turned to On.  The pump makes no sound when the key is turned to the On position and never has. Your other K75 is the first I've read about where the pump makes a whir when the key is turned to On. More information is needed to make a diagnosis.

The spark plugs, their gaps, the spark plug lead connection sequence, the water temperature sensor connection and its operating range, the overall wiring condition to the parts involved—all must be checked in turn to remedy this very common condition of used bikes that have been neglected.

[Blue]

I would take apart every electrical connector and toothbrush them with baking soda and vinegar.  Before putting them back together I would get some pig fat, also known as lard, anyway some really nice pig fat and spread it on every conector and button it up.

[Laitch]

I would take apart every electrical connector and toothbrush them with baking soda and vinegar.  Before putting them back together I would get some pig fat, also known as lard, anyway some really nice pig fat and spread it on every conector and button it up.

What do you do about the ants?

[Blue]

I would give the ants a popsicle.

[bluebossa]

Thanks guys...


Maybe I'm getting confused then with the K1100RS I owned, that definetely made the noise on key on.
Good to know.


This afternoon - took the tank off, took apart every connector, cleaned and put some WD40 on them and put them back.
Cleaned all the earths, took out the Relays and did the same.


3 Big Fat sparks so definitely no issues there - checked Gaps on plugs - couple of tweaks, cleaned them and refitted.
I still think it's fueling, Fuel pressure.


Uploaded a Video to YouTube to help... diagnose?


https://www.youtube.com/y5gTe-ixNgM

[bluebossa]

[BrickMW]

Sounds like the firing order is wrong. Have you verified correct plug wires to correct cylinders?

[bluebossa]

Yep - first link duff - but embedded above

[alexg]

I used to have starting problems on an old E36 coupe. The issue was leaky fuel injectors, that would flood the car. If I turned the engine off with a cold engine (like backing out of the garage), it will not start next day. From what I read, plugs fouled, you might have such a problem. I used to clean and dry the plugs with a hot air gun, wait for at least a day, charge the battery full, and crank the car with the gas pedal to the floor, to lean whatever mix in the cylinders.


Sent from my iPhone using Tapatalk

[bluebossa]

Thanks BrickMW - but the leads are sized exactly and haven't been moved since it was running perfectly.


It was started post build and ran perfectly for 50km then just wouldn't start and is in the mode you hear in the Video...


Sparks are all present and strong, plugs are gapped and new, Battery is charged and at 13.2.

[bluebossa]

Just another thought - when we took the tank off yesterday, there was a load of crud stirred up and settled in the Fuel Filter.
Clean the filter, flushed the Tank with petrol and refitted



I'm wondering whether some of the flakes could have reached the Injectors and blocked them?
How to diagnose and check?

[rbm]

I don't hear the pump run on for 1.5 seconds after you release the start button in the video.  Can you positively confirm that is happening?  It would point to tank connector problems.  I think the bike is farting because the fuel is just leaking into the cylinders and then enough accumulates to ignite.

[The Mighty Gryphon]

Your 1100 has a Motronic ECU which runs the fuel pump for 2 seconds when the key is turned on.  The K75 has a Jetronic ECU which turns on the fuel pump for two seconds when the starter button is pushed.  Both require a signal from the Hall Effect Sensors to keep the pump running. 

Try to start and then pull a spark plug.  Is it wet or dry?  If it is wet and you can smell fuel you may have a flooded engine.  I had a similar problem recently.  Once the engine is flooded, the enrichening of the mixture for a cold engine will keep flooding the engine with fuel.  The best way to clear the flood is to unplug the tank connector and run the starter.  It will take several seconds of burping and farting before it will fire for a second or two.  Reconnect the tank connector and try again.  The chances are good it will start.  You might have to do this a couple of times.

[bluebossa]

Hi RBM - we do hear the pump for a second or so after the start - can confirm that..

[bluebossa]

Hey the Mighty Gryphon - thanks for the tips.The Mighty Gryphon


Can confirm that the plugs are wet when we pull them. I say we as the Bike is a friend of mine and I'm lending him a hand to try and get it going.
There is a Bike night tonight in Dubai and we were doing everything we could to get it out for it's first showing.


I'll try starting it with the main Fuel pipe disconnected - think that is what you are suggesting, though guess Fuel will pump out. So need to rig a catch tank?
Also planning to Sun bake the plug to give them a dry out.. But great sparks so no issue there...

[bluebossa]

Can confirm that the plugs are wet when we pull them. I say we as the Bike is a friend of mine and I'm lending him a hand to try and get it going.
There is a Bike night tonight in Dubai and we were doing everything we could to get it out for it's first showing.




I'll try starting it with the main Fuel pipe disconnected - think that is what you are suggesting, though guess Fuel will pump out. So need to rig a catch tank?
Also planning to Sun bake the plug to give them a dry out.. But great sparks so no issue there...

[Martin]

If the plugs are wet try starting it with fuel pump fuse removed.
Regards Martin.

[bluebossa]

Thanks Martin will do... which fuse is it top to bottom?

[Martin]

Number six from the top marked Krafftstoppe on the lid.
Regards Martin.

[bluebossa]

Number six from the top marked Krafftstoppe on the lid.
Regards Martin.

Thanks Martin v Helpful..

[Laitch]

Download the K75 Rider's Manual at this link, bluebossa. You can then look up what the other fuses handle, plus learn other features of your bike.

[The Mighty Gryphon]

BlueBossa, I was referring to disconnecting the electrical connector to the tank.  That will cut the power to the fuel pump without shutting off anything else.  The idea is to crank the engine to blow out the extra fuel that is flooding the engine.  I find it is easier than trying to get the right fuse.  Once the engine is cleared out and will fire properly reconnect the connector and try starting again.  If the problem was too much fuel in the cylinders, it should now start.

[bluebossa]

So the latest installment - we (myself and Tony, the owner) still can't get it to run, we've spent 2/3 days on it now, Tank off, Tank on, Plugs in, Plugs Out.
We've so far:

• Charged the Battery and tried an additional Booster to ensure we get Max Amperes, Volts
• Latest - We took the injectors out and got them Sonic cleaned - some rust flakes were noted in the Fuel line - refitted, still won't start.
• Still got 3 Sparks - each plug when cranking, plugs cleaned, dried, re-gapped and are new. Big Blue Sparks when cranking
• Cleaned every Earth and Connector on the Bike - had every connector apart - including the ECU, cleaned, WD40 and re-fitted

At a loss now, the Bike was running after the re-build, did 50km, then overnight decided not to run again - very frustrating.

• The Pump is switching in and out, it runs for a second or so after cranking - so that means relay is working and wiring is OK - we've re terminated the Pump connectors
• Plugs have been taken out, cleaned, heat dried and we've run the engine without Fuel connected to try and burn off any excess or flooding..

Ideas still welcomed on what to try next...?
[size=78%]We're losing the plot with it now a little... [/size]