Fuel pump won't stop running

[port67]

Riding the 89 max to work & she shuts off. Just filled up so i know i have plenty of fuel. Turn the key off then back on & i hear the fuel pump clicking like mad for 5-10 seconds. Normally i hear it for about 1 sec when i turn the key on.
Pull the pump & it is pretty rough(original 89 pump). I clean out the tank,replace the filter & lines from the tank to the pump.I have an extra pump so i install it.I hold the end of the line(tank side) up & fill the filter & pump with gas & fill the tank.I turn the key & it primes for 2 seconds & stops.I cycle the key a few more times till the pump only runs for 1 second like always.Crank it up & everything seems fine; pump only comes on every 5 to 10 seconds but it runs for just a second then repeats the cycle.Come back an hour later & turn the key & she is clicking like mad again.I crank it up fine & run it for about 15 minutes but the damn pump won't stop running. I unplug the low gas sensor & try the normal & res switch in both positions but no luck. The only thing left i can think of is the relay. How do i check it & any other ideas would be great.
BP
(UPDATE) OK. I have been able to get an exact repeat of the problem 3 times in a row. When the max is cold the pump works like it should;pulsing every 5 seconds or so. When it reaches normal operating temp after 10-15 minutes the pump slowly starts to increase the cycle until it is clicking constantly.Shut it off & wait an hour & then it is fine again when i crank it until 10-15 minutes later. Same thing over & over. I don't know what to check next.

 

[maleko89]

First thing I would do is check your tip over valve mounted in front of the battery box. Also, ensure all the lines are tight including fuel tank, vent, fuel filter, pump and finally the carb rack.

Next, remove fuel line from the carb rack and aim in a bucket. Turn key on and make sure fuel is getting pumped out. It that is all good then I would take pump apart an check on the small rubber diaphragms and make sure they are fully seated. I believe there are 2. Normally I wouldn't think this is it since you are having the same problem with 2 different pumps. But, the misplaced diaphragms is a fairly normal occurrence. Mine from a '99 does this occasionally. If that's good then I would make sure you floats are stuck closed by draining the fuel out of each carb and seeing if you are getting close to the same amount out. Lastly, troubleshoot your fuel pump relay.

 

[wayne z]

The last time I rode my Vmax, about 2 months ago, I was about 20 miles from home. When I turned on the key to go home, the fuel pump kept continuos pulsing.
I started it and it ran fine on the way home, but I had a fuel system fire after 15 miles, that almost toasted the bike.
The hottest area of the burn pattern was the motor end of the fuel pump. Burned thru the wiring harness and fuel lines between the pump motor and the frame.
I found one of the rubber check valves dislodged inside the pump. This would cause constant pulsing. I also found the tip- over vent valve plugged. With sloshing gas pressurizing the tank, enough fuel gets pumped so the engine runs OK.

Kinda' suspect fire started by the pump contacs under the plasric cover may have overheated from constant pulsing for 15 miles ( last 5 at 85 mph).

So, If anyone has a constantly cycling pump ya better fix it.

BTW, the $60 aftermarket ebay pumps have interchangable parts with stock Vmax pump parts. identical construction on the basic pump. I used my original studded mount and end plate on the new pump.

 

[maleko89]

Good info, do you know the part numbers?

 

[wayne z]

No numbers but here's a link.

http://www.ebay.com/itm/FUEL-PUMP-F...s=Model:Vmax+1200&hash=item43ce31ded6&vxp=mtr

 

[Traumahawk]

Thanks.....I have it "watched" now.

 

[maleko89]

Dayum, $47?

 

[wayne z]

Yep, same vendor I used back in Dec. for $60. He must be overstocked. I might buy another for a spare. The grommet mount is just a clamp screw mount and it is easily removed and discarded.

 

[maleko89]

Yep, same vendor I used back in Dec. for $60. He must be overstocked. I might buy another for a spare. The grommet mount is just a clamp screw mount and it is easily removed and discarded.

Again, thanks for the info! I'm going to look at getting one...can't beat that price! I think I'll see what other stuff he has.

 

[blaxmax]

Riding the 89 max to work & she shuts off. Just filled up so i know i have plenty of fuel. Turn the key off then back on & i hear the fuel pump clicking like mad for 5-10 seconds. Normally i hear it for about 1 sec when i turn the key on.
Pull the pump & it is pretty rough(original 89 pump). I clean out the tank,replace the filter & lines from the tank to the pump.I have an extra pump so i install it.I hold the end of the line(tank side) up & fill the filter & pump with gas & fill the tank.I turn the key & it primes for 2 seconds & stops.I cycle the key a few more times till the pump only runs for 1 second like always.Crank it up & everything seems fine; pump only comes on every 5 to 10 seconds but it runs for just a second then repeats the cycle.Come back an hour later & turn the key & she is clicking like mad again.I crank it up fine & run it for about 15 minutes but the damn pump won't stop running. I unplug the low gas sensor & try the normal & res switch in both positions but no luck. The only thing left i can think of is the relay. How do i check it & any other ideas would be great.
BP

Take the pump apart-it is easy- and inside you will find 2 small rubber diaphragms- one will be out of place- it needs to be bubble side up and flat side down. When you put it back to the way it is supposed to be it will run normal again.

 

[wayne z]

Take the pump apart-it is easy- and inside you will find 2 small rubber diaphragms- one will be out of place- it needs to be bubble side up and flat side down. When you put it back to the way it is supposed to be it will run normal again.

That is exactly what I did to my pump. When I went thru the entire fuel system of this bike, after sitting 4 years, the pump was cycling and I took it apart and found the unplugged rubber valve, plugged it back in and the pump worked fine afterward, only pulsing a few seconds when switching on the key. Less than 200 miles later it popped out again and I think it might have had something to do with causing my fire.

If the valve popped out once, it will soon pop out again, as mine did. I don't recomend trying to fix a 25 or 30 year old pump.

 

[port67]

It can't be the tip over valve. I am doing all the tests with the gas cap off;so air getting into the tank isn't the problem. It seems impossible that a new pump would get stuck after only running for 15-20 minutes.Fuel isn't pouring out of the carbs so i don't think a float is stuck. Does it matter if the fuel pump itself is grounded or not? With the old pump the rubber grommets on the mount bracket looked like there was no metal to metal contact between the pump & mount bracket. But on my new pump i had to change the mounting bracket so now the pump is grounded to the frame. Will this affect the way the relay works? The motor is running & idling fine.

 

[maleko89]

It can't be the tip over valve. I am doing all the tests with the gas cap off;so air getting into the tank isn't the problem. It seems impossible that a new pump would get stuck after only running for 15-20 minutes.Fuel isn't pouring out of the carbs so i don't think a float is stuck. Does it matter if the fuel pump itself is grounded or not? With the old pump the rubber grommets on the mount bracket looked like there was no metal to metal contact between the pump & mount bracket. But on my new pump i had to change the mounting bracket so now the pump is grounded to the frame. Will this affect the way the relay works? The motor is running & idling fine.

I don't think the pump needs to be grounded...it'll work whether mounted on the bike or not.

I would pull the pump and check the diaphragms.

 

[blaxmax]

There are 2 rubber diaphragms --- one has flipped over.

 

[wayne z]

How old is this pump?

 

[huskyman510]

There are 2 rubber diaphragms --- one has flipped over.

+1 to this
Had the same issue this week, first thing I did was pull the pump, took it apart, hey look rubber diaphragms had moved.
Refitted all and ALL GOOD!

 

[maleko89]

Port67 tried a second fuel pump and is getting the exact same symptoms. It's unlikely that two pumps would do the same thing but still a wise idea to open up the pump to make sure. There are three diagnostic testing diagrams in the service manual and advised him to do those and make sure fuel lines are tight. Finally, test/replace fuel pump relay and fuel sender. Stupid question. How full is your gas tank?

 

[wayne z]

+1 to this
Had the same issue this week, first thing I did was pull the pump, took it apart, hey look rubber diaphragms had moved.
Refitted all and ALL GOOD!

If it popped out once it will pop out again. Mine went about 200 miles before it happened again. Fuel pump caught fire that same day after constant cycling, on a 20 mile ride towards home.

 

[D-Max2012]

I remember that the only time my pump kept running longer than normal was when I emptied out my float bowls. It had to keep running to build back pressure before the pump would stop. Also when I had a stuck adjustment tab on one of floats, It kept the float valve from closing fully, allowing fuel to leak out of the overflow tubes, and of course, not allowing the back pressure to build.