Crank, no start on 94 K75

[rdivy725]

Greetings,

I have been chasing an interm hot soak crank, no start condition on my K75 (after a long ride and 25 minutes of sitting). A couple of days ago, after sitting two weeks, it started and shut back off again and wouldn't restart for a couple of minutes. I took it for a ride and one time it hiccupped and then ran good for an hour. Come out yesterday, crank no start. I have spark. Checked fuel system fuse and power at the fuse and relay. Checked 4 pin connector to the tank, power on green/white wire when cranking. Pulled the tank and looked inside, both fuel pump terminals took the slightest tweek but still no start or pump noise. I checked continuity and this is where i need assistance as I am leaning towards the fuel level sender. I could not fit my fat hand and see wtf I was doing trying to get my multimeter lead to the sender contacts. But when I touched the opening of the tank and had a lead connected to the green/white wire I have continuity. In fact, 3 of the 4 have continuity to the tank except for the brown wire. Why would three of the pins have continuity with the tank? Thanks in advance

[Laitch]

When you crank the starter but the engine doesn't start, do you hear the fuel pump whine for a couple of seconds after you finally release the starter button?

[rdivy725]

Laitch,

I do not hear the pump whine. The last time I reattached the tank to the bike I had the fuel lines loose and no fuel came out when cranking. Still had voltage at the connector. I am guessing next step is to pull the pump and put 12v to it to see if it runs, then pull the fuel sender and check it closer. There is NO corrosion on anything inside the tank - it only has 11k miles on it but many years , I have seen horror pics on this site of other bikes internal tanks but everything looks new.

[Martin]

I very high percentage of non starts is caused by the 4 pin connector. The infamous 4pin connector can have power on the input side but when connected still not have power to the pump. You can try cleaning with DeOxit which can work, however sometimes the best method to insure it's continuing cooperation is to replace it with a good quality waterproof connector. These can be obtained from your local electronics supply store.
Regards Martin.

[Ted]

In fact, 3 of the 4 have continuity to the tank except for the brown wire. Why would three of the pins have continuity with the tank?

Had a similar starting problem this week (power to green-white, but no pump), and found one of the black wires in the tank, from the pump to the base of the fuel levelsender, loose. The solder joint had broken. I can imagine that if such a loose wire would touch the tank somewhere you could measure continuity to the tank through all exterior wires except the brown one.

Just a thought...

[technostructural]

I've had the exact same issue, though in my case there was no continuity between the male end of the 4-pin connector and the solders on the sender unit inside of the tank. I even tried by putting my multimeter probe on the back side of the 4-pin connector (where the crimp is) to rule out something wrong with the 4-pin itself.

In my case at least, the continuity issue is somewhere within that 90 degree, white plastic, gas/liquid sealed connection that goes from outside of the tank to the inside. I wish it were just the 4-pin, but the 4-pin had perfect continuity on both sides when tested.

So, in my case, I need a whole new damn sender unit which is not cheap. I recommend doing every multimeter/continuity test you can think of.

Have you bench tested the pump by giving it 12v to see if it works? It's probably the least likely to have failed but it's worth knowing.

[rdivy725]

Thank you Ted and Technostructural. I did pull the pump out completely and put 12v to her, she spun right up and spit gas 6 feet. I am going to pull the sending unit out later this week when I get back home and bench check it. I just can't get into it to test with it sitting in the tank. Then I will either order a sending unit, an o ring or a 4 way connector. The continuity to the tank on the three wires (except ground) is what has me baffled. It may very well be in the 90 degree. The hot soak restart concern that led up to this could certainly be heat off the engine at the sender. Stay tuned.

[volador]

4 pin configuration on the male end of the Petrol Gauge Level Sender

1.Brown-is ground continuity to the larger diameter ring terminal

2.Green-is 12V continuity to the smaller diameter ring terminal

3.Yellow-is fuel level

4.White-is 4 litre reserve indicator

Remove the ring terminals from the fuel pump to perform the continuity test

Easter Beaver Sumitomo TS090 Sealed Connectors

the 'Sumitomo Not in Catalog Male 4P Connector'  3/4 of the page down sleek discreet connector

get extra pins and seals

[technostructural]

Thank you Ted and Technostructural. I did pull the pump out completely and put 12v to her, she spun right up and spit gas 6 feet. I am going to pull the sending unit out later this week when I get back home and bench check it. I just can't get into it to test with it sitting in the tank. Then I will either order a sending unit, an o ring or a 4 way connector. The continuity to the tank on the three wires (except ground) is what has me baffled. It may very well be in the 90 degree. The hot soak restart concern that led up to this could certainly be heat off the engine at the sender. Stay tuned.

As Volador indicated, one thing you can check before pulling the whole sending unit is whether you are getting continuity between the male end of the 4-pin and the two leads that go to the pump inside of the tank. They are long enough that you can pull them outside of the tank through where the fill cap normally sits. I believe the white/yellow lead to the fuel pump will correspond with the solid green on the male end of the 4-pin, and the black lead from the fuel pump will correspond to the brown wire on the 4-pin.

If you test this and do not have continuity, then it may be worth pulling the sender to see if there is a split in the wire sheathing or maybe damage at one of the solders on the sender. The sender comes out fairly easily (4 big philips screws) but you may want to soak them in penetrating oil for a bit first. Mine took a bit of persuasion.

Good luck.

[rdivy725]

Checked wiring today with pump out, sender still in the tank.

1. Checked continuity from green terminal at the 4 way to yellow connection for the pump - have continuity on it only and no other terminals in the 4 way

2. Check Brown wire (ground) at the 4 way to black connection for fuel pump, have continuity (and I have checked for ground on the bike side as well, good ground)

3. Check Yellow wire at the 4 way, no continuity to pump or tank (this is for the gauge, mine is not equipped)

4. Check White terminal at 4 way, have continuity both at black wire to pump AND continuity at tank. This is for the low fuel light indicator in the dash

#4 is what has me suspect to pulling the sending unit and checking

[Martin]

You will only have power to the fuel pump wires in the tank when pressing the starter button.
Regards Martin.

[rdivy725]

Martin, I have 12V from the bike to the 4 way when starter button engaged (but fuel pump does not run). That is why I pulled the tank, tested the pump and started checking wiring. I am hung up on the white wire at the 4 way going to ground. That does not seem right and I am not sure how that impacts the fuel pump from running.

Readings below for the wiring:

Checked wiring today with pump out, sender still in the tank.

1. Checked continuity from green terminal at the 4 way to yellow connection for the pump - have continuity on it only and no other terminals in the 4 way

2. Check Brown wire (ground) at the 4 way to black connection for fuel pump, have continuity (and I have checked for ground on the bike side as well, good ground)

3. Check Yellow wire at the 4 way, no continuity to pump or tank (this is for the gauge, mine is not equipped)

4. Check White terminal at 4 way, have continuity both at black wire to pump AND continuity at tank. This is for the low fuel light indicator in the dash

[technostructural]

This is peculiar. If you have continuity for both leads to the pump itself (black and yellow) to (respectively) brown and green, AND you are getting 12v from the female end of the plug when pressing the starter, AND your fuel pump works when given 12v... I am a bit out of ideas for what could be causing it.

In my case, there was no continuity between the yellow pump lead and the green pin in the male end of the 4-pin connector. This was the culprit, and I traced it back to that 90 degree white plastic fitting in the sender. I just received my new sender in the mail yesterday, installed it, and my pump now runs. I did not fire up the bike completely yet but it seems as though the issue has been resolved.

In your case, I am a bit confused as to what it could be if there is good continuity all around.

[rdivy725]

This is peculiar. If you have continuity for both leads to the pump itself (black and yellow) to (respectively) brown and green, AND you are getting 12v from the female end of the plug when pressing the starter, AND your fuel pump works when given 12v... I am a bit out of ideas for what could be causing it.

In my case, there was no continuity between the yellow pump lead and the green pin in the male end of the 4-pin connector. This was the culprit, and I traced it back to that 90 degree white plastic fitting in the sender. I just received my new sender in the mail yesterday, installed it, and my pump now runs. I did not fire up the bike completely yet but it seems as though the issue has been resolved.

In your case, I am a bit confused as to what it could be if there is good continuity all around.

Techno, since you have everything back together - can you check for continuity at the 4 way (sender side) between the white and brown wire? This will determine next steps for me. Thanks in advance

[Scott_]

Sounds to me that if you have power present at the pins on one half of the 4pin connector, and continuity to the pump on the other half of the connector, yet still no pump operation, I've venture to bet you need to replace the 4pin connector...
Not uncommon for them to go bad and not make contact when connected together.

[rdivy725]

Sounds to me that if you have power present at the pins on one half of the 4pin connector, and continuity to the pump on the other half of the connector, yet still no pump operation, I've venture to bet you need to replace the 4pin connector...
Not uncommon for them to go bad and not make contact when connected together.

Scott I am 95% there with you - just need to know if, at the fuel sender side of the 4 way, it normal for the white wire (bulb indicator light)  to have continuity with ground (brown wire). If someone could test this for me It would tell me my next steps.

[Laitch]

Scott I am 95% there with you - just need to know if, at the fuel sender side of the 4 way, it normal for the white wire (bulb indicator light)  to have continuity with ground (brown wire).

If you lift the sender's float arm while testing, do you lose continuity?

[rdivy725]

Laitch - yes, I lose continuity when I lift the float, which educates me that when the fuel level gets below the threshold the circuit goes to ground, illuminatng the low fuel indicator light. So 4 way it is. Going to replace the fuel damper (just starting to come apart), fuel lines and filter while it is apart.

Thanks all . Just needed to understand how it works.

[Laitch]

 

[rdivy725]

4 pin configuration on the male end of the Petrol Gauge Level Sender

1.Brown-is ground continuity to the larger diameter ring terminal

2.Green-is 12V continuity to the smaller diameter ring terminal

3.Yellow-is fuel level

4.White-is 4 litre reserve indicator

Remove the ring terminals from the fuel pump to perform the continuity test

Easter Beaver Sumitomo TS090 Sealed Connectors

the 'Sumitomo Not in Catalog Male 4P Connector'  3/4 of the page down sleek discreet connector

get extra pins and seals

Volador,


What gauge wire connector do I need to get? 14-16 or 18-24?

Thanks in advance

[technostructural]

My apologies, I have been out of the loop for a few busy days.

I will check this as soon as possible for you. I can confirm that everything is now back together and it runs. For me, it was the wiring in the 90 degree white plastic fitting in the bottom of the sender.

[rdivy725]

Latest update. Replaced the 4 pin connector. Pump still does not run. But now I have extra terminals to plug in and test. I run 12v to the pump through the tank side connector, pump runs. Check voltage at bike side 4 way connector (Green wire) AND at power side of fuse I have 5.86 volts when cranking, when I let off the starter switch it spikes to about 11.5 volts then goes to 0 volts. I know the starter is going to take some juice but shouldn't I have close to 12V at the pump? Ground is good on the brown wire, both sides.  I want to back trace from the fuse box to the relays BUT my relay layout doesn't match any I have seen on here (or the web). According to my schematics and other sources, there should be a fuel pump relay to check. I have included a image of the relay box to try and get clarification.





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[Laitch]

Check voltage at bike side 4 way connector (Green wire) AND at power side of fuse I have 5.86 volts when cranking, . . . I know the starter is going to take some juice but shouldn't I have close to 12V at the pump?

Yes.

As far as the relay box diagrams go, they're all over the map. Contents is dependent on the moto's year and the modifications of previous owners, too. How many five-pin relays are in that box?

[rdivy725]

So, another learning experience on the BRICK. The long and short is the 4 way connector was buggered, but so was the 4 pin FI relay in the box. I have been chasing looking for a 5 pin relay when it is actually, for this model year, a 4 pin (Make sure you find the RIGHT schematic!). I was able to get a layout for my bikes relays and I checked for power (12v) and output when cranking (5.8v). I swapped the relay with the horn relay (now 12v output) and she runs (and now the horn doesn't work!). I had replaced these relays last year (load shed and horn specifically to fix a concern) and I thought the third relay was for the fan. I replaced it anyway. Im wondering if the internal issue with the 4 pin caused the relay to go bad? The

So now I know my fuel pump and sender circuit A-Z.

Green and red wire from the relay pictured below (to fuse box) had 5.8v cranking with old relay.

While I was inside the tank I replaced the rubber pump isolator, fuel filter and submersible rubber lines. I replaced the 4 pin connector.

Thank you all for the help and suggestions.

[Laitch]