Fuel Pump Relay

[Donvito]

I posted last week about a problem with my fuel pump system so I spent a week testing the relay output at start, while running, hot, cold, with the headlight plugged in, with the relay hanging and installed, and no problems. Put it back together and went for a ride yesterday. Today, I went to start it and the problem occurred. The relay clicks rapidly but no power to the pump. By the time I got it opened to test it was working.

 

Now I can't find a relay to buy even though I'm not sure if that's the problem. When the problem happens, the starter cranks and nothing else seems to be affected. I tested the ground at the relay and it was good but I'm not sure where it's grounded to. Can someone tell me? Also, if there is anything else I can test let me know. It's frustrating when I can't test it while it's happening. Thanks.

[bongobobny]

From our technical Read Only library. Kudos to Dingy for the excellent job on redrawing the schematics!

 

http://www.venturerider.org/forum/showthread.php?t=42358

[Flyinfool]

For intermittent electrical problems, I have hooked up a LED idiot light to different points on the suspected circuit to find where the failure point is.

In your case connect a LED across the fuel pump. This will tell you if it is getting power during the failure. If the LED goes out at the same time as the pump goes out you then know the failure is something other than the pump, if the light stays on but the pump goes out then the problem is the pump. each time you verify a component with the LED, move the LED to a different part of the circuit.

 

There is nothing tougher than finding an intermittent issue, especially while on the road.

[Donvito]

Thank you both for the helpful advice. My understanding, please correct if wrong, is the relay is powered by turning the ignition switch which then sends power to the fuel pump for several seconds before turning off. Once the engine starts, the ignitor determines the bike is running and sends a constant signal to the relay to power the pump which is continuously powered until the bike is turned off or the engine is stopped from another system.

 

As I have experienced problems at start and while the engine is running, what is common to both conditions? I understand the relay and pump are, but, is there something else? I don't think the sidestand switch effects the fuel pump nor the "fall over" sensor other than to stop the engine, which, in turn, causes the ignitor to stop the relay from powering the pump. Correct?

[Flyinfool]

When you first turn on the key, will the engine crank with the starter button? Will it start?

Even if the fuel pump is not running, it should still start and run till the float bowls run out of fuel.

 

When you said that the relay was clicking rapidly when you turned on the key.

It is normal for the fuel pump to click rapidly and it does sound like a relay clicking. Are you sure it is the relay that you are hearing clicking and not the fuel pump?

 

IF the float bowls are already full you will not hear any clicking when you first turn on the key. The fuel pump only clicks while it is pumping, once the system is full it will not click anymore till there is someplace for it to pump fuel into.

Edited March 18, 2014 by Flyinfool

[Donvito]

When you first turn on the key, will the engine crank with the starter button? Will it start?

Even if the fuel pump is not running, it should still start and run till the float bowls run out of fuel.

 

When you said that the relay was clicking rapidly when you turned on the key.

It is normal for the fuel pump to click rapidly and it does sound like a relay clicking. Are you sure it is the relay that you are hearing clicking and not the fuel pump?

 

IF the float bowls are already full you will not hear any clicking when you first turn on the key. The fuel pump only clicks while it is pumping, once the system is full it will not click anymore till there is someplace for it to pump fuel into.

 

When the problem occurs the engine will start and run until it stalls, Then, after a period of time and turning the key, I will hear the pump click and it will run fine, usually until I turn it off although it did stall one time while running. Every other time the problem has occurred at start up.

 

I know the difference between the pump clicking and the relay clicking and, when the problem occurs, it is definitely the relay clicking.

 

I understand the pump will only pump when the carb requires gas and it is continuously powered while the engine is running but will only pump as needed. When it is operating properly, I can see this on my tester. But, I have not been able to test during the problem yet.

 

As I have been testing it all last week, but running the engine and not riding it, I haven't had the problem. It seems to only happen after a ride. Does that mean anything?

[bongobobny]

You are correct in your understanding of the relay operation. That being said, what Jeff said! The relay does not click, the fuel pump clicks. The contacts on the fuel pump are known to go bad, and unless your fuel filter is in good shape it can shut off fuel delivery to the carbs. Also, remove your petcock and screen and inspect them. If the screen gets clogged it will shut down the supply of gas to the fuel pump and that will make the fuel pump click rapidly the same as it does when you run out of gas...

[bongobobny]

You posted while I was typing. Once again, the relay only clicks twice, once with key on, and again when spark is detected. After that it never clicks again until you turn the key off and then back on. If you are hearing the relay click, then either you have an intermittent somewhere or the relay is defective...

[Donvito]

You are correct in your understanding of the relay operation. That being said, what Jeff said! The relay does not click, the fuel pump clicks. The contacts on the fuel pump are known to go bad, and unless your fuel filter is in good shape it can shut off fuel delivery to the carbs. Also, remove your petcock and screen and inspect them. If the screen gets clogged it will shut down the supply of gas to the fuel pump and that will make the fuel pump click rapidly the same as it does when you run out of gas...

 

When the problem first happened, I removed the fuel hose at the pump and drained several pints of fuel because I though it was bad gas. So, I don't think fuel supply to the pump is the problem. I have checked the filter and it's good but I'll remove and inspect the petcock and screen.

 

The rapid clicking is definitely coming from the area of the relay, not the pump. I'm familiar with the pump sound as I've owned the bike since 1987. Once the event is over, the pump clicks and the bike runs fine. Thanks for your advice.

[Donvito]

I was just able to test while the problem was occurring. When the relay clicks repeatedly and the pump doesn't operate, the voltage at the relay is less than 10. I tested the headlight also, and that is reading 12 volts. After the clicking stops, it also hums/vibrates briefly. I held it in my hand while this was happening so the clicking IS coming from the relay.

 

I tested the relay at the power supply (R/W) and at the fuel pump wire (L/B) and they are both low. So, sometimes, there is insufficient power going to the relay and, consequently, the pump. The starter will work while the problem is happening and, as I said, there is 12 volts going to the headlight.

 

Trying to trace the R/W wire on the schematic, it seems to supply power to the sidestand relay, flashers and some other components and is fed from the ignition fuse. I suck at schematics so if anyone can help there I'd appreciate it.

 

What could cause intermittent decreased voltage going to the relay?

[Flyinfool]

If the voltage on the red/white wire is low and all other wires are still at 12 V then you have a bad connection somewhere.

 

This will take a while to walk you thru this, there are a lot of connections in that red/white wire.

Please do not be upset if we go down to to low of a level, we do not know your experience level.

 

Start at the very beginning with the fuse block. Do you still have the stock fuse panel with the glass fuses?

If you can get the bike into the condition where you are seeing low voltage on the red/white wire at the relay. Check the voltage on both sides of the Ignition fuse (15A fuse) this is the beginning of the red/white wire. Do not just touch the ends of the fuse but get to the wires themselves.

 

Try not to move the wires while testing them, you might just move them into a good position from the bad position they were in.

[Donvito]

If the voltage on the red/white wire is low and all other wires are still at 12 V then you have a bad connection somewhere.

 

This will take a while to walk you thru this, there are a lot of connections in that red/white wire.

Please do not be upset if we go down to to low of a level, we do not know your experience level.

 

Start at the very beginning with the fuse block. Do you still have the stock fuse panel with the glass fuses?

If you can get the bike into the condition where you are seeing low voltage on the red/white wire at the relay. Check the voltage on both sides of the Ignition fuse (15A fuse) this is the beginning of the red/white wire. Do not just touch the ends of the fuse but get to the wires themselves.

 

Try not to move the wires while testing them, you might just move them into a good position from the bad position they were in.

 

Yes, still have the glass fuses. Ignition fuse tests 12.25V at left and right side wire terminals. R/W wire at relay 10 V not running. At idle, 13.3 V at fuse, 11V at relay. Thanks.

I have to go out for a few hours so will reply next asap. Thanks.

Edited March 18, 2014 by Donvito

[Flyinfool]

The glass fuses in these bike are very well known to cause a lot of electrical grief. It is highly recommended to replace the glass fuse panel with an AGM fuse panel. Skydoc_17 sells a kit with good instructions on how to do this.

Although if you have 12V in the wires at the fuse panel then that is not likely your issue at this time.

 

The next place that the red white wire goes is to the kill switch on the right handlebar.

 

The wire bundle that comes down from the handlebar has a connector in the right side of the faring. If you already are in to the relay then you should also be able to get to this connector.

There are 2 red/white wires in that connector. Check to see if they both show 12V while the relay is showing 10. If one of the wires has 10V and the other 12V. then you have a dirty contact in either the connector or the switch its self. The switch can be disassembled for cleaning the contacts. Give each of the wire a gentle tug to be sure it is well crimped, Last summer I had a loose crimp in that connector that drove me nuts for over a month trying to find find my intermittent connection.

[Flyinfool]

In case you are interested here is the thread that I made while I was chasing my intermittent electrical issues. Coincidentally mine also involved the red/white wire......

Unfortunately I became fairly intimate with that red/white circuit....

http://www.venturerider.org/forum/showthread.php?t=79290

Edited March 18, 2014 by Flyinfool

[Donvito]

The glass fuses in these bike are very well known to cause a lot of electrical grief. It is highly recommended to replace the glass fuse panel with an AGM fuse panel. Skydoc_17 sells a kit with good instructions on how to do this.

Although if you have 12V in the wires at the fuse panel then that is not likely your issue at this time.

 

The next place that the red white wire goes is to the kill switch on the right handlebar.

 

The wire bundle that comes down from the handlebar has a connector in the right side of the faring. If you already are in to the relay then you should also be able to get to this connector.

There are 2 red/white wires in that connector. Check to see if they both show 12V while the relay is showing 10. If one of the wires has 10V and the other 12V. then you have a dirty contact in either the connector or the switch its self. The switch can be disassembled for cleaning the contacts. Give each of the wire a gentle tug to be sure it is well crimped, Last summer I had a loose crimp in that connector that drove me nuts for over a month trying to find find my intermittent connection.

 

I have 12 volts at the plug but only from one of the R/W wires, the other has no voltage. I'm testing with the plug unplugged, the key on and the bike not running. Trying to trace the wires on the schematic, it looks like one goes to the sidestand switch and the other to the ignition coils, is that correct? Why wouldn't there be power to one of the wires? I also tried testing with the start button pushed and the sidestand up and down.

 

Also, currently I have 12 volts at the fuel pump relay and it is operating properly.

 

Thanks.

[dingy]

Would a fuel pump relay help you?

 

I have I spare I will loan you. I opened it up a while back to see what was in it.

 

Does bike have cruise control on it? If it does, indicator lights are fed from same circuit that powers pump relay. Turn cruise on and watch to see if lights go out. Set, Resume & On all have same 12v+ feed.

 

Gary

[Flyinfool]

If you unplugged the connector then there will only be 12V on one of the red/white wires.

as a test, hook a jumper across the red/white wires in the connecter to see what the voltage is at the relay.

[Donvito]

Would a fuel pump relay help you?

 

I have I spare I will loan you. I opened it up a while back to see what was in it.

 

Does bike have cruise control on it? If it does, indicator lights are fed from same circuit that powers pump relay. Turn cruise on and watch to see if lights go out. Set, Resume & On all have same 12v+ feed.

 

Gary

 

Thank you for the offer. Not sure it's the relay at this point but if everything points to that, I'll take you up on your offer to confirm that's the problem before I buy one. Thanks for the info about the cruise control and, yes, I have it.

[Donvito]

If you unplugged the connector then there will only be 12V on one of the red/white wires.

as a test, hook a jumper across the red/white wires in the connecter to see what the voltage is at the relay.

 

OK, I don't have small enough connectors to make a jumper so have to buy some. I did notice something that you may be able to explain. With the petcock closed, the voltage drops 2 volts at the R/W wire at the relay and at the wire going to the pump. This happens whether the engine is running or not. So, if I turn on the key with the petcock closed, the relay will click and the voltage is at about 10. Then, when I open the petcock, after a few minutes, the voltage goes back to normal and the pump operates. Any thoughts?

 

Have to go to work. Keeps getting in the way of working on the bike.

[Flyinfool]

???

You mean the fuel petcock?

That should have no effect at all on voltages. I have to think about this one now.

[dingy]

Can you disconnect fuel line to carbs at fuel pump?

 

Then put 12v + & - to fuel pump leads, after disconnecting from harness.

 

Reason being is it would be interesting to see if fuel pump is funcioning as it should with power direct to it.

 

Only way closing petcock could have any effect on voltage is that the plunger inside the fuel pump is not able to retract after it is cycled foward, this possibly could prevent the contacts from opening as they should on the return stroke of the plunger. There may be an issue in the pump solenoid windings that is drawing down voltage.

 

Other than that, petcock & electrical systems are totally unrelated. Also the flapper valves may be malfuntioning in pump.

 

Gary

[Donvito]

Yesterday, I was tying to cause the problem so I ran the bike with the fuel petcock closed until it stalled. I wanted to empty the carbs so the pump would operate. After doing this, I forgot to reopen the petcock and had 10 volts at the relay which caused the relay to click and vibrate, which is the same thing it was doing when the bike wouldn't run. When I opened the petcock, the pump operated and the voltage returned to 12.

 

Currently I have 12 volts at the test points. I'm pretty sure I can cause the problem again by closing the petcock and running the bike until it stalls but I don't know if I could cause damage by doing it. Even though I have disconnected the fuel line from the pump and drained fuel at what seemed to be sufficient flow, I think I should drain the tank and check the screens at the petcock in addition to continuing to check the electrical system. I had assumed a restricted fuel flow had no effect on the relay voltage but now I'm rethinking that.

 

What do you think and what should I check next?

[dingy]

Can you disconnect fuel line to carbs at fuel pump?

 

Then put 12v + & - to fuel pump leads, after disconnecting from harness.

 

Reason being is it would be interesting to see if fuel pump is functioning as it should with power direct to it.

 

 

Gary

 

Yesterday, I was tying to cause the problem so I ran the bike with the fuel petcock closed until it stalled. I wanted to empty the carbs so the pump would operate. After doing this, I forgot to reopen the petcock and had 10 volts at the relay which caused the relay to click and vibrate, which is the same thing it was doing when the bike wouldn't run. When I opened the petcock, the pump operated and the voltage returned to 12.

 

Currently I have 12 volts at the test points. I'm pretty sure I can cause the problem again by closing the petcock and running the bike until it stalls but I don't know if I could cause damage by doing it. Even though I have disconnected the fuel line from the pump and drained fuel at what seemed to be sufficient flow, I think I should drain the tank and check the screens at the petcock in addition to continuing to check the electrical system. I had assumed a restricted fuel flow had no effect on the relay voltage but now I'm rethinking that.

 

What do you think and what should I check next?

 

If you want to drain fuel, use pump as noted above and see if it operates correctly with direct power to it.

 

Gary

[Donvito]

Can you disconnect fuel line to carbs at fuel pump?

 

Then put 12v + & - to fuel pump leads, after disconnecting from harness.

 

Reason being is it would be interesting to see if fuel pump is funcioning as it should with power direct to it.

 

Only way closing petcock could have any effect on voltage is that the plunger inside the fuel pump is not able to retract after it is cycled foward, this possibly could prevent the contacts from opening as they should on the return stroke of the plunger. There may be an issue in the pump solenoid windings that is drawing down voltage.

 

Other than that, petcock & electrical systems are totally unrelated. Also the flapper valves may be malfuntioning in pump.

 

Gary

 

Thanks for the suggestion. I know the pump operates when it's getting 12 volts to it. So, after I drain the tank and check the petcock I'll confirm the pump operation. Since you understand the pump operation, what does it do when the fuel flow is not sufficient due to an obstruction in the supply system?