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"How To" Test Your Fuel Pump

23K views 31 replies 16 participants last post by  porkadian 
#1 ·
Ok, so I've seen where a few people have been asking on how to tell if your fuel pump is bad.
I had someone tell me how to do this, So I'm passing it on to you guy's.
There is an easy way to test it yourself.

Remove your seat.
Pull the black fuel line that feeds the fuel rail,
put the open end into the measuring cup.
Turn the ignition on for 4 seconds only.(Be Precise)
If there is less than 1/3rd cup. Fuel pump needs replacing.
If there is 1/3rd or more, fuel pump is good.
 
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#3 ·
will be checking this ASAP hoping its just my plugs making it run like doodoo right now bec i had an extra pump last week, but its been sold...
 
#10 ·
A difference for the Gen 4:
With the fuel line disconnected from the fuel rail, the fuel pump should stop after three seconds. Per the service manual, the amount of fuel collected over the three seconds should be:
Amount of Fuel Flow
Standard: 67 mL (2.3 US oz.) or more for 3 seconds​
Which is around 30% or more of a cup.

Also the fuel pressure at idle (measured with an oil pressure gauge off a T-hose on a test fuel line):
Fuel Pressure (with Engine Idling)
Standard: 294 kPa (3.0 kgf/cm², 43 psi)​

• If the fuel pressure is much higher than specified, replace the fuel pump because the fuel pressure regulator in the fuel pump have been clogged or stuck.

• If the fuel pressure is much lower than specified, check the following:
Fuel Line Leakage​
 
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#12 ·
2011 Gen 4

My current issue is that the fuel pump isn't priming when the key is switched on. I checked the IG fuse but is there another fuse or a relay I can check for the fuel pump?

Can I jump it with a 9V or 12V power adaptor for a second or two to make sure it's not the pump itself?

The dash flashes the fuel light and yes she has gas... Thx
 
#17 ·
should work if the signals are the same, you maybe able to get away with using a single relay for the one that is bad but would require some splicing and wiring plus testing but it's possible....basically the relay box is just that housing a few relays in ONE box nothing special.

Bloo
 
#19 ·
yeah if signals and connectors are the same you shouldn't have to pay more...then there is fitment...if all those are the same it should be good to go using another but sounds like you're not sure yet...you really need to make sure it's the problem first it's just a relay you can test it most times off the bike....especially in this case if it's a matter of on and OFF.

bloo
 
#20 ·
bloo,

So you got me thinking and I attempted to test red and tan w/ yellow strip pins on the main relay and the ohms does change from " 1 " to " 0.2 " using the "20K" setting. Does this mean the relay is or has the ability to close like it should?

This is all new to me so sorry if this doesn't make sense...
 
#21 ·
you can apply 12v to the relay and there need another voltmeter to see if the the other 2 wires close.....basically there is already 12V on one side of the relay and the circuit applies ground then the Voltage needed is applied to the Fuel pump...this takes 4 wires for all this to happen if your not comfortable doing this test best to have someone that is...bottom line easy to check the Relay but keep in mind off the bench may give false results when in circuit because of bad wiring, corrosion etc causing the relay to fluctuate or bad contact.

bloo
 
#24 ·
I pulled the other end off the tank, put my own pipe on there and ran that into a cup because it disturbed less.

I used a spray can cap, measured its diameter and depth and marked off a line showing 76ml, the 4 second prime must exceed this.
 
#26 ·
If you are putting out 1/2 cup of fuel or more within the time specified, it passes that portion of the test. However, you would still need to test fuel pressure before you can give the pump assembly a clean bill of health.

If you believe you are having fueling issues, be sure to replace the fuel filter/pickup mounted on the fuel pump. Kawasaki claims they cannot be replaced, however they are available on eBay for around $10 with free shipping. I recently changed mine out and it was absolutely horrible, full of black grit and other crap.

While my pump still passed the flow test even with the nasty filter, the engine idle fuel pressure was low. After replacement, I gained about 6psi, putting it within spec.
 

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#32 ·
Ok, so I've seen where a few people have been asking on how to tell if your fuel pump is bad. I had someone tell me how to do this, So I'm passing it on to you guy's. There is an easy way to test it yourself. Remove your seat. Pull the black fuel line that feeds the fuel rail, put the open end into the measuring cup. Turn the ignition on for 4 seconds only.(Be Precise) If there is less than 1/3rd cup. Fuel pump needs replacing. If there is 1/3rd or more, fuel pump is good.
What size should the cup be?
 
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