'86 VFR700F: diagnosed bad fuel pump - please confirm

Please confirm my bad FP diagnosis:

Stalled while riding the other day - first throttle response became intermittent, then the engine shut down. Came to a stop, restarted with open choke, it ran for a few seconds, then died again.

I have gas, fuel valve is open, electrical system is good (checked it recently). Started checking the fuel pump. First thing I noticed is that I have continuity across the two wires going into the pump, with AND without them connected to the fuel pump relay. Figured this can't be good. Disconnected the pump outlet hose, jumped the fuel relay connector and cranked the bike for several seconds (per FSM) - a few drops of fuel came out, but that's it. While ignition was on, the pump was making a very rapid clicking noise, which stopped after I turned the key off. If I disconnect the inlet hose and open the fuel valve, gas pours out.

Conclusion - bad pump. Yes?

 

Plugged filter? Pump clicking means it's working. Or at least trying to. Take the filter off then hook pump inlet up to fuel and output to a container. Then hook the pump straight to 12v. I think white is 12v and black is ground. See if it pumps fuel.

 

Thanks, I'll give it a shot tomorrow.

 

Fuel pump......if it clicks, it works. You need to pull off lines to prove fuel from tank flows to pump.

Yes, if your pump is in working condition, it will show some continuity across the plug terminals.

Rapid clicking without slowing down means that fuel from the tank is probably not flowing TO the pump.


Pump relays fail more often than pumps.

Pump works like a heart, and both inlet and output valves can get clogged with crap. Blow into the intake side, then suck on the output side (through a rag so you don't suck fuel), and air should flow but NOT in the reverse direction on either valve.

 

on some of the older bikes i have seen people put the tank selector valves on weird like 1 of my vf1kr's it would run out of fuel on a full tank of gas while in the on position and it would run fine in the off position, and not run in the reserve, it was weird but pulled the valve apart and found the internals clocked improperly.. its just a thought if the above doesnt work.. if after it sets for a bit and you go to start it and it runs. could be a fuel filter and the fuel is slowly trickling by. is the inside of your tank clean.. if its a lil rusty then over tym that rust will plug up a filter.. remember you wil have to crank the bike for the fuel filter to run so listen carefully for a tic or series of tics right after you stop cranking.. the electronics shuts the fuel pump off when its not running. and as soon as the coils start to fire the relay for the fp engages.

 

This isn't it because I've verified fuel valve operation - in 'off', no fuel comes out of the tank. In 'on' fuel comes out of the tank.

Yes, good idea. Sounds like the fuel filter needs to be taken out of the loop for a proper check.

So, my next steps will be:
1) Bypass the fuel filter and go from tank straight to fuel pump
2) Jump the fuel pump relay connector, just like I did before, crank and see if fuel comes out of the pump
3) Try this in both 'on' and 'reserve' positions of the fuel valve.

BTW, where is the reserve located? Is it just the bottom of the tank?

Thanks for all your help guys.

 

Is your tank vent in the cap clear?

 

Well, I'm an idiot. But being a newb to motorcycles, I don't feel too bad. I ran out of gas.

The reason I didn't think I ran out of gas is because when the bike first stalled on me, switching to reserve didn't help. Is it possible to completely run out with the fuel valve in the 'on' position? I didn't think so. And then I looked inside the tank and there was a little fuel sloshing around the bottom of the tank, so I figured - eh, I have gas.

But when I was troubleshooting it this weekend, I followed the steps above and after I noticed that nothing was coming out of the tank, that's when I realize what really happened. Anyways, I'm happy that I didn't have to replace the fuel pump!

Followup - any negative consequences to running out of gas as far as the motorcycle is concerned?

 

better you have something silly happen like that than a real, difficult to troubleshoot issue

 

So what's this tell you?

If the fuel valve was in the "ON" position and you ran out of gas. Then your fuel valve is bad. It's letting fuel flow from the reserve part all the time. Sure the valve was fully on the "ON" portion of the valve or could it have been in between. I'm not familiar with a 86 fuel valve.

 

Just posting about it on this forum.... you are BRAVE.. the ridicule pointing and laughing has already commenced on your behalf.... ound:

what did we learn boys and girls.... when we have what we think is a fuel problem... CHECK for fuel first!!!!

seriously, glad it was nothing mere than an empty tank....

 

I don't care! Laugh all you want, I'd do the same thing.

To GreyVF750F - the valve cannot be in the in-between position, because the in-between position is "off". "on" and "reserve" are at 180 degrees from each other on the valve knob.

I do want to check the fuel valve to make sure it doesn't draw from reserve when set to 'on'...

 

If you do it (run out of gas) near an on ramp like I did you might get hit by a car and take an ambulance ride to see if you leg is broken and have insurance not pick up a penny of the $950, 10 mile ambulance ride.
Then there is medical costs, getting your bike out of impound (dude at the counter was surprised I was there walking so quickly to get my bike after seeing the wreck) and having to salvage parts to get it to run properly again. All in all probably about a 3 or 4 thousand dollar fiasco because I thought I could make it a few miles more to the gas station.

So yeah, bad things can happen if you run out of gas at the wrong time.