Bad fuel pump I think...Please Help!

Aero540T · 07-06-2007, 05:55 PM

I just picked up a Yamaha FZR600 and the day after I took it home I went to start it and heard some clicking noise from under the seat (fuel pump) and realized I forgot to turn on the fuel...Oops. I tried again with the fuel on and nothing happened.

I talked to our local dealer and he suggested to take the fuel line from the pump to carb off and try putting the kill switch to run and see if fuel shoots out. I just tried that and it does squirt fuel out (to prime the engine) but the pump makes a lot of noise while doing it, pulsing pretty good and whatnot. So i hooked the line up again and tried it and it pulsed a little bit but not for the whole 5 seconds...

Do I need a new fuel pump or could this be something else? I'm not sure how a dying fuel pump acts!!

scatterbrained · 07-06-2007, 05:58 PM

If that is the same as the FZR 1000 I wouldn't worry about it. The fuel pump doesn't run all the time, its just there to keep the float bowls full. It should click for a while if the bike has been off to prime up the system, then shut down. A problem I ran into with mine was the intank sensor going bad and not killing the fuel pump. I'd run out of gas without ever having switched the switch to reserve.
how does it run?

Aero540T · 07-06-2007, 06:04 PM

Quote:

Originally Posted by scatterbrained

If that is the same as the FZR 1000 I wouldn't worry about it. The fuel pump doesn't run all the time, its just there to keep the float bowls full. It should click for a while if the bike has been off to prime up the system, then shut down. A problem I ran into with mine was the intank sensor going bad and not killing the fuel pump. I'd run out of gas without ever having switched the switch to reserve.
how does it run?

I know the 1000 has the pump attached to the frame while the 600 and 750 are on the tank (as per the Haynes manual), but other than that I don't know.

It seems to me that it should hum rather than click and pulse the way it does (I'm new to bikes though so correct me if I'm wrong).
The problem though is that with a tube hooked up to the line it goes the entire 5 seconds pumping gas into my container, but when I hook the carb line back up it quits after a second or two and the bike WON'T fire up (it turns over fine).

scatterbrained · 07-06-2007, 06:19 PM

a cars pump will hum because it is rotating, an FZR's pump is an electric solenoid moving a rubber diaphragm, hence the clicking. It quits because the floats are full, the positive pressure against the diaphragm tells the pump to stop. It will go on forever till it builds pressure. Check for spark first if the bike won't start. Then fuel at the cylinder. I bet if you crack the bleed screw on the float bowls you'll get a lot of gas out, if so then you'd have enough to start with.

Aero540T · 07-06-2007, 07:24 PM

I won't be able to check for spark today, is the screwdriver method still ok to use?

The only reason I kept/keep thinking it's the fuel pump is how quickly this happened. I started it up Sunday night and it went fine, then probably twelve hours later on Monday it wouldn't, how could it happen overnight?

scatterbrained · 07-06-2007, 07:30 PM

Having judgments of what it will be before doing a thorough diagnosis will leave you chasing your tail without a solution. Start by checking the basics:Fuses, battery voltage, spark, fuel, compression. It could be something as simple as fouled plugs.

Aero540T · 07-06-2007, 07:43 PM

Yeah I know what you mean, I just had my mind set on the fuel pump before really understanding it.
Though I do credit myself for checking the fuses and battery voltage first, I did something right!

But let me just put this into words so I get what you're saying. You're saying the fuel pump is probably shutting off early because the float bowls are already full, meaning it has no reason to go the full span?

Thanks, btw, for the quick responses, I'm just frustrated it won't run the day after I bought it...

scatterbrained · 07-06-2007, 07:54 PM

I'll give you a quick explanation of how my FZR's fuel system works, yours should be the same. The fuel pump is a solenoid activated diaphragm; it contracts the diaphragm to ingest fuel, and pushes forward to expel the gas to the carbs, when it can't push out (line pressure) it stops. From then on your carbs will do most of the work with the pump only coming on occasionally to refill the carbs. The pump is a passthrough design so it doesn't need to be running for gas to move through it, unlike a rotary pump that will impede flow if it isn't moving. The ignition system gets it's signal from the crank. It's a very basic and reliable system. Usually the most likely culprit is plugs or there's no gas.
The bike doesn't have a regular petcock regulated reserve. It has a sensor in the tank that kills the pump in extended position till you flip the switch to reserve. Once you hit the switch the pump kicks back in and off you go. If the tank sensor goes out the bike will run through the whole tank without ever stopping till you're completely out of gas.

Has the bike been in the rain or washed since you bought it? You may have a connection that is bad.

Aero540T · 07-06-2007, 08:03 PM

Thanks for the explanation

Here's the story, I went to the guy's house and had him start it up and ride it around the block to make sure it looked and sounded good, blah blah blah. I then trailered it home, started it up for my mom and girlfriend just to show them, and put it in the garage. The next day at lunch I tried to start it just because I was excited I got a bike and wanted to hear the engine and it wouldn't go.

I was able to get it to fire up a couple times rocking the throttle open and closed but it died after a second or two. After those couple times, it wouldn't fire up. It's just so strange

Aero540T · 07-06-2007, 08:22 PM

ok so i got determined and I just did check all four wires and they had a good spark so tomorrow if I have time I'm going to have to pull the radiator and remove the plugs and replace if I have to. If that doesn't work I'll let you all know

scatterbrained · 07-06-2007, 09:22 PM

shouldn't need to lift the radiator just lift the tank.
Are you using the choke?
Carbed bikes don't like to be started then shut off. Pull the plugs and clean them or replace them if the electrodes look rounded off.

Aero540T · 07-06-2007, 09:55 PM

Thanks for the tip, I'll let you know how it goes

Aero540T · 07-09-2007, 06:33 PM

By the way on this bike the plugs are right behind the radiator, so there's only a couple bolts to undo and you can swing it away far enough to get there. Lifting the tank would have been more of a PITA and wouldn't have helped to get to the plugs.

Anyways, my friend picked up the plugs for me and I put them in and BAM fired right up. Bike sounds great, I can't wait to ride it.

Also, I put in a couple ounces of Seafoam in the tank just in case because I don't know how often it had been ridden previously.

Oh and thanks for the help!

Aero540T · 07-09-2007, 06:42 PM

OMG...as I typed that post I had the bike idling in the driveway, I hear a loud buzzing noise and run outside to see smoke coming from the rear of the bike and coolant all over the ground.

I don't know what the buzzing noise was because I shut it off immediately, but I assume it was an overheat warning?

All I did was change the plugs!

gboezio · 07-09-2007, 08:02 PM

Did a rad hose blowed up ??