K75s Not starting

[Smistik]

Hi! My first topic here...If I start from the begining of problems with this bike... First time I got total dying when riding It was fuel tank/sender connector issue. Changed new sender (used one) and changed whole 4-pin connector to new water restistant one. Then I got bike working and rode many times. Then I got again this same total dying problem and could not get bike running anymore. Finally when I made some voltage test in fuse #6 I did not get voltage. I removed the FI relay, and noticed that one of the cables was very deep inside the relay terminal. I removed the terminal and pushed all cables to touch fully to relay legs. And then bike was alive again. Last summer I got again same problem. During riding bike just dies and was cranking but not starting. I let it cool down and then it was alive again. It happened several times and then I thougth that it might problem with HES. I tried heat gun staright to HES when idling, but did not get bike die.

When I was starting my season here (Finland) couple of weeks ago, I purchased new coolant temperature sensor, new temperature relay, new FI relay,  new thermostat and flushed radiator and motor and then applied new coolant. I was pretty sure it was temperature sensor as I old one was giving 4500ohms when room temperature. I got bike running and made small trip and boom...it died again after 20 kilometers. I let it cool down a bit and it was cranking, and got it rough idle for two-three seconds and then nothing. I got the bike back home and started to investigate, put battery charging full but it is cranking but not getting whirring sound from fuel pump after pressing start button. I checked FI relay is getting ~12V at #86 and at #85 it is getting something like 0.1V when hitting start. Also Fuse #6 is not getting any volts to left leg. FI relay cables are sitting 100% in their places.

What should be checked next?

[rbm]

First, don't measure the resistance of the water temperature sensor between both pins on the connector; that is the wrong method.  Measure the resistance between either one of the pins and the main body of the sensor. 

If you are not getting the fuel pump to run on for 1.5 seconds after releasing the start button, then you have a problem with the electrics to the pump.
1. disconnect the fuel pump at the harness on the right side of the battery.
2. attach a DC voltmeter between the Green/White wire on the HARNESS side of the connector and a ground point
3. Turn on the ignition and press the start button for a second or two and then release the button; watch the voltmeter throughout this procedure
4a. If the voltmeter goes to 12V and remains at 12V for 1.5 seconds after releasing the button, then your problem is not with the ECU / ICU on the bike, it is with the wiring to the pump or the pump itself
4b. If the voltmeter does not go to 12V or does not remain at 12V after releasing the button, your problem is with the bike electronics and not the pump.

If it's the pump:
5. measure the resistance between the Green/White wire and Brown wire on the TANK side of the pump connector.  It should read about 120 Ohms or so.
6. while continuing to do this resistance measurement, carefully wiggle the cable leading to the tank and the wires going to the pump inside the tank.  Watch for variations in the resistance during this procedure.
There's only a few suspects - the fuel pump, the fuel level sender, the new 4-pin connector or the cable to the tank.

If it's the bike:
5. Reseat the connectors for BOTH the ECU (under the seat) and ICU (under the tank).  Do this several times in a row.  Don't be ham fisted as you don't want to bend pins or distort the contacts in the connector shells.

That's all for now.  Report back with any findings.

[johnny]

greetings...

thats right... and at no time be ham fisted...

j o

[LeMoeur]

While you’re at it, if you find point 4a or 4b to be true, try and check the voltage between ground and key switch wire. It’s a connector located under the tank on the right side, synthomps makes me suspect for a dirty ignition switch.

[Smistik]

Thanks for advices!

First, don't measure the resistance of the water temperature sensor between both pins on the connector; that is the wrong method.  Measure the resistance between either one of the pins and the main body of the sensor. 

If you are not getting the fuel pump to run on for 1.5 seconds after releasing the start button, then you have a problem with the electrics to the pump.
1. disconnect the fuel pump at the harness on the right side of the battery.
2. attach a DC voltmeter between the Green/White wire on the HARNESS side of the connector and a ground point
3. Turn on the ignition and press the start button for a second or two and then release the button; watch the voltmeter throughout this procedure
4a. If the voltmeter goes to 12V and remains at 12V for 1.5 seconds after releasing the button, then your problem is not with the ECU / ICU on the bike, it is with the wiring to the pump or the pump itself
4b. If the voltmeter does not go to 12V or does not remain at 12V after releasing the button, your problem is with the bike electronics and not the pump.

When pressing start button it was giving 11.25V for a second when attached to green/white cable.

If it's the pump:
5. measure the resistance between the Green/White wire and Brown wire on the TANK side of the pump connector.  It should read about 120 Ohms or so.

No resistance. I checked also old fuel sending unit, it was not givin resistance either.

6. while continuing to do this resistance measurement, carefully wiggle the cable leading to the tank and the wires going to the pump inside the tank.  Watch for variations in the resistance during this procedure.
There's only a few suspects - the fuel pump, the fuel level sender, the new 4-pin connector or the cable to the tank.

If it's the bike:
5. Reseat the connectors for BOTH the ECU (under the seat) and ICU (under the tank).  Do this several times in a row.  Don't be ham fisted as you don't want to bend pins or distort the contacts in the connector shells.

That's all for now.  Report back with any findings.

I also gave +12V to tank connector from other battery. Nothing happened. So it may be the sending unit or pump I guess?

[Smistik]

While you’re at it, if you find point 4a or 4b to be true, try and check the voltage between ground and key switch wire. It’s a connector located under the tank on the right side, synthomps makes me suspect for a dirty ignition switch.

I have cleaned switch last summer and also did today. It is clean for sure.

[rbm]

When pressing start button it was giving 11.25V for a second when attached to green/white cable.

It's not so much the exact value you get (11.25 versus 12V or 12.5), rather it's whether the voltage remains for 1.5 seconds following the release of the start button.  Your response doesn't confirm nor deny this claim.  Can you confirm that the voltage remained??

I also gave +12V to tank connector from other battery. Nothing happened. So it may be the sending unit or pump I guess?

It's looking more and more like the sending unit or its wiring. I'd concentrate on diagnosing that area of the bike over all others.

One suggestion is to temporarily connect separate wires to the pump terminals.  USE CAUTION!!! (yes, I'm yelling)
- use firm attachment methods such as alligator clips or ring terminals attached to the pump posts
- make certain that the wires cannot touch in the tank; an explosion could result.
- make sure the wires are a couple metres long so that you attach the battery far away from the gas tank to avoid an explosion should there be sparks
- Make sure the tank connector is detached from the harness when you conduct this test

Touch the wires to an external battery and see of the pump is OK. I suspect that it is ok, but you never know until you confirm it.

If the pump runs in this configuration, then your only remaining problem area is the sender unit or the attached wiring.

[Smistik]

When cranking it stays over 11V for around one second and then I hear relay click and voltage drops to zero.

Next I will drain the tank and try feeding 12V to pump skipping sender unit.

[Smistik]

So, I have now emptied the tank and removed fuel pump. It is working when I give 12V from external battery. I was not working via sending unit. I have also old sending unit which do not give current to fuel pump if connected to it. So maybe I have 2 broken sending units? I measured resistance from both units and they have resistance in ground wire, but not in yellow + wire if measured from tank connector end to fuel pump connector end.

[Smistik]

So, I have now emptied the tank and removed fuel pump. It is working when I give 12V from external battery. I was not working via sending unit. I have also old sending unit which do not give current to fuel pump if connected to it. So maybe I have 2 broken sending units? I measured resistance from both units and they have resistance in ground wire, but not in yellow + wire if measured from tank connector end to fuel pump connector end.

Sorry I measured wrong cable. I made it again from green wire to fuel pump end and "new" sender which is now in tank is not giving resistance bu old one is giving ~2.7ohms and fuel pump works via it. I have to change it to tank and give a try.

[Smistik]

 :riding:  It is alive  :yow :yow But I cannot test ride it as I need my wife to get it back home on trailer if it acts like idiot. Thanks mates for helpful comments. New Sending unit will cost 180€ in Germany, so it is my next step if it stalls again...