Four Wheel Forum

Another dumb question. The fuel pump is supposed to hum when turned on right? I turned the ignition on today for the first time with a new battery in years. The lights came on the dash and the controls seemed to work but I didn't hear anything from the fuel pump. I can check the connector for power tomorrow with a test light I suppose. I elected to call it a day when I got the fuel hooked up and I didn't hear the pump turn on. I don't know what position to turn on the fuel selector so I figured I would find out the answer to both these problems and get back at it tomorrow. Hopefully she'll fire up. ANd I hope I don't have any fuel leaks as well.

Connecting the fuel lines:

So I checked to see if I was getting any power to the plug that goes to the fuel pump and that turned out to be not energized. Maybe that's why this bike was pushed to the sidelines in the first place years ago?

Next I made a couple jumper wires to connect the ground and positive pump wires to the battery. It was pulling juice but the pump was not vibrating at all. I then took off the fuel feed hose to the carburetors and put a foot long length of clear tube on it so that when I did power it next then the fuel would hopefully come out into the bucket. No dice! So the Kawasaki fuel pump is not working - probably frozen from old fuel that dried up inside it.

I did indeed take the fuel line from the ZX-7R petcock off to make sure that fuel was getting down to the pump so fuel supply is not a problem.

Well I guess the next step is to buy a new fuel pump. Not looking forward to buying this item.

Did you disconnect the harness? There are several things that have to be in order for the pump to work on the ZX7.

Best way to check the pump with the harness on is to put the bike in gear, turn the key on, make sure the kill switch is off and have a FULLY charged battery. These things are fickle with voltage. The pump does not make much noise, so you have to touch it to feel if it is working.

If that does not work, make sure the fuel pump relay is connected. It is a small black box with a red connector in the corner. These can fail and is more likely the issue.

If that is not it you may have a bad key switch. There is a resistor in the key switch that reduces the voltage as a theft deterrent. If the CDI sees 12 volts direct it shuts down the fuel pump and the coils. Do you have spark? If both are out it is either the key switch or not enough voltage from the battery.

If it is the fuel pump they are common to the ZX6, ZX7 and ZX9. Not hard to find but still not cheap.

I was hoping it was just an old fashioned setup without any fancy anti-theft stuff. I have a new battery and I hooked it directly to the battery and it didn't vibrate, make a noise let alone pump any fuel. I should have a new one in my hands by Thursday. I still need to check the pump relay to make sure it's fully operational. I didn't think I got power from it but I'll go back and check it using your advice.

The bike was shut off and parked back when it was put away to everything should be operational so I'm hoping everything checks out ok.

Alright I was looking at the Clymer manual wiring diagram of this ZX-7R and the fuel pump doesn't get power just by turning the ignition switch on. I noticed that the starter button actuates the pump and I'm pretty sure that once the bike starts that the pump is powered from then on out. I guess this keeps the pump from just running while you have it parked with the key on. I guess that's a good thing.

The pump works great and I used the jumper wires to pressurize the fuel system to check for those leaks so that was a good idea after all. I'm just glad I didn't order a relay thinking that was the problem. And what a noise that little pump makes. Reminds me of a hyper aquarium pump that rattles a little but of course once it pressurizes it stops until the pressure drops in the carbs. The old fuel pump was definitely toast.

Here are a few pictures of my new fuel pump install going on. The fuel pump cost about $165 by the time tax was added on. Then I spent another $30 on premium Honda fuel lines which IMO are the best fuel hoses you can get.



And here it is! Brand new and ready to pump fuel into the thirsty Keihin carburetors.


With a couple 10mm head bolts removed the fuel pump bracket comes off the engine allowing you to swap out the surrounding fuel pump rubber isolator much easier.

Now to test the new fuel pump and also to prime the fuel system to check for leaks in your hoses or carbs you can simply make some jumper wires to feed power directly from the battery to the fuel pump plug. The fuel pump only comes on when the ignition is turned to "on" and the starter button is pressed. Then when the engine is running power is also fed to the pump but when the key is just switched "on" and the bike is not running there won't be any power. So this little jumper wire helps out. Pretty easy to do. I cut down a couple connectors so they would fit in the tiny fuel pump connector. Then I put an alligator clip on the positive side. I just left the negative one hooked up all the time. I'll take it off when the bike is ready to hit the road.

Here's a closeup of the fuel pump plug with my wire adapters. They are basic 2 prong spade connectors with one side cut off.

And just for good measure a couple videos. The first showing me connecting the jumpers to turn on the fuel pump to check operation: And the next video with fuel poured into the tank and checking that it actually is pumping and is stopping once fuel pressure is adequate. Working fine now: