Kawasaki Ninja ZX-6R Forum banner

Fuel pump is hit or miss when ignition is turned on?

2326 Views 29 Replies 6 Participants Last post by  Mattel
I'm having problems with my race bike.
It is hit or miss when I turn the key. Sometimes the rule pump comes on, sometimes it does not. Everything else lights up and is normal.

I tried wiggling all the connections and I can't figure it out?

Any suggestions?

It's not the ECU, I had replaced it and the problem continues.

When I'm all leathered up and about to get out on the track I turn the key and the starter cranks, but no fuel pump.... No starting...
I have to take my helmet off and put my ear to the tank to listen for the humm of the fuel pump and keep turning the key on and off without doing anything else, just the key before hitting the starter.

Any suggestions?
1 - 20 of 30 Posts
If u can....lift the tank when the pump is stuck. Test voltage at the terminals. Thatll tell u if its the pump thats failing or if its something else and its cutting power to the pump.
  • Like
Reactions: 2
If u can....lift the tank when the pump is stuck. Test voltage at the terminals. Thatll tell u if its the pump thats failing or if its something else and its cutting power to the pump.
Great idea! Thanks ...

Any other suggestions?

I may just put a set of jumpers on those wires and leave the tank down.

Come on guys, I will post the result on this.

I'm also going to be selling a cool flash tune ECU soon. Great product!!!
I'm having problems with my race bike.
It is hit or miss when I turn the key. Sometimes the rule pump comes on, sometimes it does not. Everything else lights up and is normal.

I tried wiggling all the connections and I can't figure it out?

Any suggestions?

It's not the ECU, I had replaced it and the problem continues.

When I'm all leathered up and about to get out on the track I turn the key and the starter cranks, but no fuel pump.... No starting...
I have to take my helmet off and put my ear to the tank to listen for the humm of the fuel pump and keep turning the key on and off without doing anything else, just the key before hitting the starter.

Any suggestions?
A few things to check.

1) Ensure there is no corrosion between the contacts and the leads.
2) check the crimp of the contacts.... see if you can compress them a bit (very slightly) to make a more solid contact pin to pin.
3) Verify the retaining mechanism on the connector bodies is still good. if the latch backs off slightly, it may make for intermittent contact.

Once you've done all of that, it may be time to pull the pump and do an operational check on it outside of the tank.

Could also be a flaky relay that is supposed to provide power to the pump; look at all the connections in that path as well.

Come to think of it the pressure regulator that shuts the pump off when the rail is at the right pressure..... you might want to see if that's okay.

Do you get any fault codes when this happens?
See less See more
A few things to check.

1) Ensure there is no corrosion between the contacts and the leads.
2) check the crimp of the contacts.... see if you can compress them a bit (very slightly) to make a more solid contact pin to pin.
3) Verify the retaining mechanism on the connector bodies is still good. if the latch backs off slightly, it may make for intermittent contact.

Once you've done all of that, it may be time to pull the pump and do an operational check on it outside of the tank.

Could also be a flaky relay that is supposed to provide power to the pump; look at all the connections in that path as well.

Come to think of it the pressure regulator that shuts the pump off when the rail is at the right pressure..... you might want to see if that's okay.

Do you get any fault codes when this happens?
Will do that. NO error codes. It just lights the dash but I don't hear the buzz of the pump.
My guess is the pressure regulator on the rail is supposed to open or close a contact to indicate the pressure in the rail is right.... if the sending unit sticks in the 'I'm full' position, the fuel pump would never be commanded to come on.

What I don't know is which state indicates what. Is the pressure transducer normally closed, or normally open? Does all of that pass through the ECU, or is it independent of that?

If you pull the pump, and it runs with direct connections to the power source, that indicates a logic problem in the control circuitry. That's all low power stuff, so it's likely to be harder to spot.
OK, I'm still learning electrical but I am a quick learner.

I have three wires coming off the fuel pump. I want to test it for power when I turn on the ignition.
Wires are Black / lt.blue stripe
Black / yellow stripe
Wite / red stripe

Which wires do I connect to the red and black multimeter and what setting on the meeter?
OK, I'm still learning electrical but I am a quick learner.

I have three wires coming off the starter motor. I want to test it for power when I turn on the ignition.
Wires are Black / lt.blue stripe
Black / yellow stripe
Wite / red stripe

Which wires do I connect to the red and black multimeter and what setting on the meeter?

I have the manual which walks through the test for the starter relay. I will do that first.
I don't think the starter motor will have power available until you hit the starter button. The ignition switch should not directly energize the starter.... it will have to go through a few relays before power gets to the starter.

Ignition>idiot switches (neutral, side stand, clutch> (ECU?) > starter button > relay> starter solenoid > motor.
  • Like
Reactions: 1
I don't think the starter motor will have power available until you hit the starter button. The ignition switch should not directly energize the fuel pump.... it will have to go through a few relays before power gets to the fuel pump.

Ignition>idiot switches (neutral, side stand, clutch> (ECU?) > starter button > relay> starter solenoid > motor.

Sorry...brain fart.. I ment fuel pump....
  • Like
Reactions: 1
Mine has done this for about 2 years. It's the fuel pump relay I'm pretty sure. I just give the tank a "WHACK!" and she goes... bzzzzzzzzzrrrrrr...
  • Like
Reactions: 1
Mine has done this for about 2 years. It's the fuel pump relay I'm pretty sure. I just give the tank a "WHACK!" and she goes... bzzzzzzzzzrrrrrr...
Speaking from experience. Can't get better than that.
  • Like
Reactions: 2
New development...

I removed the wire for the fuel pump. And the bike still made the buzzing sound when I turn the key, and it is still hit or miss.

QUESTION: What makes the buzzing sound when you turn the key if its not the fuel pump?

And would that be what is wrong with the bike? IM not into fixes that require me to slap the tank like a cheap whore when I'm leathered up.
  • Like
Reactions: 1
New development...

I removed the wire for the fuel pump. And the bike still made the buzzing sound when I turn the key, and it is still hit or miss.

QUESTION: What makes the buzzing sound when you turn the key if its not the fuel pump?

And would that be what is wrong with the bike? IM not into fixes that require me to slap the tank like a cheap whore when I'm leathered up.
My next guess would be a chattering relay.
  • Like
Reactions: 1
My next guess would be a chattering relay.
I'm guessing it's a relay too?

Which one, and how do I check it?

Is it the fuel rail one? Seems to b comming from that area?
Dig into it and hear from where exactly the buzzing is comin from.
  • Like
Reactions: 1
I'm guessing it's a relay too?

Which one, and how do I check it?

Is it the fuel rail one? Seems to b comming from that area?
The one that energizes the pump. If you can figure that out, the check is to see if the relay will change states when you put 12 VDC across the coil. If it makes a solid 'click' without the buzzing you're hearing, the coil is okay.

With the relay unplugged and loose in your hand, the other check you need to do is between the common pin and the normally closed to see if the wiper is making contact. A low Ohms reading there, would show the moving element that makes the change in state is complete.
  • Like
Reactions: 1
Dig into it and hear from where exactly the buzzing is comin from.
I figured out where the buzz is comming from.



It is located below where my finger points to.

It does not matter whether the fuel pump is plugged or unplugged.
Turn the key and I can hear a buzz that last about 3/4 a second.

It is below where the plugs r. If I hold the plugs I can't feel it directly.

What would be in that spot that would relate to the ignition and whether the fuel pump turns on or not?

Where is the fuel rail sensor located?

Would the fuel pump relay even matter if this goes on and off without the fuel pump connected?

Help please, track days r comming fast!!!
See less See more
Looks like ur pointing at ur #2 secondary injector? Thats not even supposed to come on until 8 or 10k rpms.
  • Like
Reactions: 1
I would presume you are pointing at the secondary injector fuel rail. If you are hearing buzzing there, my guess is that it is a vibration you are hearing. I would check the security of the brackets and bolts that mount up the rail to see if anything has loosened up. Can't say that I think that is directly related to the fueling issue.....

In the photo, it looks like the rubber line connected to the end of the rail is split at the point of attachment. What is the condition of that fuel line/drain line, and how about all of the other rubber bits in the system?
  • Like
Reactions: 1
1 - 20 of 30 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top