Fuel feed problems PART II

[Seaking]

Ok folks.. I've gotten a lot of work done to the bike today and here's what I discovered and I'm STILL puzzled by the WTF factor lol.. wow

 

2006 Midnight Special, 36,900 miles on it.. (NO warranty on it at all.. don't ask, there isn't any)

 

Initial problem was that when the fuel level got to the reserve level (around 3 bars or less) and the bike starts to choke, I would select RES and the bike dies, though it is confirmed to still have it's reserve fuel amount (yes, the level is properly selected to RES, not off, not ON). Once the bike is refueled, and lever set to ON from RES, it will start once again with full choke on and then all is good as normal..

 

Once was a fluke, twice is a problem so I had to start working on it.. Everything is fine but the bike wouldn't give me an F on the fuel or a yellow light.. just cough and die when I would select to RES.

 

SO, this would indicate a blocked standpipe in the tank.. I drained the fuel with the level set to "ON" and let it go until it stopped.. then selected RES where I would assume nothing would flow but Huh?? It flowed full force again.. what the heck? This is contrary to what I was getting on the road.. twice!!

 

I pulled the petcock out of the tank to examine it, expecting to see sludge or what ever.. brilliantly clear and clean.. the fuel drained from the bike was clean.. I took a lint free cloth to wipe a little bit of the inside of the tank to see if there was a sludge coating or something at the bottom of the tank and nothing.. all clean.. well then.. what gives?

 

With the ignition turned ON, and absolutely no fuel in the tank, the fuel gauge reads nothing but there is no empty fuel light or F on the odo..

 

I removed the tank from the bike to change the spark plugs and gave it a roll over to swish it out a bit and hoping to hear the fuel level float inside but didn't hear it.. I would assume it's working as it does indicate fuel amount.. The local Yamaha dealership suggested that I have the interior of the tank "steam cleaned" at the local radiator shop to make sure no gunk or junk is left inside.. But I hesitate on that one for obvious reasons.. and no one here has ever heard of "Heat" or H33T what ever it's called..

 

I pulled the fuel filter out (ever pull the teeth out of an elephant from it's rear? this is similar!) and it didn't show any odd signs of contamination so it got replaced on spec anyway.. All the fuel lines were 'puff tested' to make sure they were clear and not blocked (spit, caff caff) And the vent line as well at the top of the tank..

 

So now, the only thing left is to swish the tank again with clean fuel to catch maybe perhaps something else that might in there.. and try this test all over again..

 

Can someone confirm that when I put fuel back into the tank and turn the ignition ON, I should indeed hear the pump tick tick tick as it fills the lines again? Is this correct and that failure to hear the pump might indicate a fuel pump malfunction?

 

Or is it possible then I am possibly looking at a 'computer' problem??

 

Later today, I will run the bike with it's new filters (air & fuel), spark plugs and such and see what happens.. I'll run it in RES and ON mode to see if that makes a prob..

 

The only prob if I can't resolve this fuel issue is that I will have to ensure I refuel just as I hit 3 bars as then I don't know when I will 'run out of fuel' as it were, while still carrying a reserve amount that I can't access..

 

Any of this sound familiar to you guys? Any thoughts or ideas?

 

Man.. what a day!!

 

Cheers

[Squeeze]

I'm not sure about your Bike's Wireing and Function, but when it's like the 1Gen Vmax, the Fuel Light Sender Unit doesn't work.

 

On a Vmax, there's no Gauge, but only a Fuel Light, if the Light lits, you have to switch the electric Reserve Switch to "Res" to get the Fuel Pump running again.

 

Now, you mentioned a Gauge on your Bike, this isn't in contrary to the above, because the Gauge is a independent Sensor with a Floater inside the Tank. The Floater Unit is measured for Resistance(400 Ohm when Full, Zero Ohm when empty to the Gauge Cluster.

 

The "Res" Light is driven by the Fuel Pump Relay. The FPR sends a Voltage (around 5 Volts) to the Sensor. This Voltage cause the NTC Sensor inside the Tank to heat up. As long as the Sensor is covered with Fuel, it is cooled by the Fuel and therefore the whole Circuit remains on higher Resistance. When the Sensor is not cooled anymore(by low Fuel or the Bike leaning over), the Sensor goes to almost Zero Resistance which causes the "Res" Light to lit. When the "Res" lits, the FPR stops feeding the Fuel Pump (by taking off Ground from the FPR) until the "Res"-Switch is switched, which causes a second Ground Connection by another Ground Wire to the FPR.

 

Sounds complicated, yes but, you need to measure the Wires.

 

I'm sorry to say, but since i have limited Knowledge about your Bike, i might not be helpful in the deeper Diagnose on your Bike. This needs a 2Genner to take over.

[Reaney in NH]

I have what may sound like a stupid question... but it would explain your problem.

 

Are you Sure you are switching from "ON" to "RESERVE"?? And not from "RESERVE" to "ON" ?

If you are driving with the fuel petcock in the Reserve position and run out of fuel then switching it....

 

The On position on my bike is the LONG side pointing down ... OFF is the long side pointing Forward... Reserve is Longside pointing UP.

 

Sorry if this sounds dumb... But its a thought.

[Seaking]

I have what may sound like a stupid question... but it would explain your problem.

 

Are you Sure you are switching from "ON" to "RESERVE"?? And not from "RESERVE" to "ON" ?

If you are driving with the fuel petcock in the Reserve position and run out of fuel then switching it....

 

The On position on my bike is the LONG side pointing down ... OFF is the long side pointing Forward... Reserve is Longside pointing UP.

 

Sorry if this sounds dumb... But its a thought.

 

 

As mentioned in initial post, it is in the proper yes, proper position.. it's an obvious miss for many but its in the proper position as shown in many manuals etc etc and some more etcs.

 

but thanks for the effort..

[Seaking]

Ok, here I am in the garage with a hijacked wireless connection (so many unsecure wireless in my friend's neighborhood)

 

I poured 3L into the tank and fired the bike up. I did NOT hear the pump kick in though but after a cough and a sputter, the bike started with the valve in the ON position.. Hmmm and the F on the ODO came on and the low fuel light came on.. nice! I switched it to RES and it still ran.. ok.. I left it running and it took 10 mins or so to cough cough and boom.. that's it.. she's dead..

 

problem is, I can\t get the bike started again.. argh! I refueled the bike with 10L of fuel and tried everything.. not happening.. I am not sure if it's a continuation of the existing problem or if I played with the idle speed setting too much and now its out of whack..??

 

Is there a quick and dirty way to reset the idle speed setting to get back to ground zero, so to speak?

 

I dunno if I'm this close or that far from being finished.. and stressed out.. sigh

 

beach slapping whom ever wrote Yamaha's technical books is a step in the right direction.. however I did manage to sort out my start problem and got the bike started and running smooth and proper again and ready for a test ride... but thanks, the rains have started lol.. egads

 

I won't know until I drain out this tank if my original issue is resolved or not..

 

what was funny is that I found a lot of funny stuff the previous owner had done to the bike and found a lot of his missing hardware, which would explain some of the buckshee bolts and nuts on this bike lol

 

going to bed now..

Edited June 4, 2009 by Seaking

[frogmaster]

Seems you can not duplicate this in a stationary position (from what I read this only occurs when in actual operation).

 

Questions:

 

Do you hear an "Air Sucking Sound" when opening the Fuel Cap?

 

Original Fuel Cap?

 

Checked the Vent Tubes?

[Seaking]

Seems you can not duplicate this in a stationary position (from what I read this only occurs when in actual operation).

 

Questions:

 

Do you hear an "Air Sucking Sound" when opening the Fuel Cap?

 

Original Fuel Cap?

 

Checked the Vent Tubes?

 

Yep some of that was mentioned in the original post.. everything is good as advertised..

 

Doing the fuel run tomorrow and hopefully everything is sorted out but we'll find out.

 

Its possible that I pooched the idle set screw while doing the first start and that resulted in a mixed of problems related or unrelated to the whole initial problem..

 

I'll let you know tomorrow after the run. It may be a computer problem as well..