Strange Fuel Day

[lyndon]

We returned this week from one of our summer camping trips and parked the bus on a nearby city street for a couple days, where it wouldn't bother anyone until we had a chance to clean it out. After starting it again, it ran for about a minute, shuddered and stalled. I restarted it a couple of times but could not keep it running, so assumed a fuel problem.

My first thought was to pick up a couple of fuel filters and see if that would solve it, but then noticed the tank sounded pretty hollow. In the 9 years since we bought the bus, my gauge has always been accurate, so I had fallen into the trap of actually believing the 3/8 reading. Dipping a socket on a string convinced me that it was lower than that so we picked up a couple of jerry cans of fuel (40+ liters or about 10 gal.).

By now, I had cranked it enough to lose prime, so I assembled a garden sprayer primer (as recommend in several past threads here -- and I can't tell you how many awesome tips I learned from the great people on this forum). After slowly pumping a couple of gallons through the system, the bus fired right up on the first try. Good thing, too, because I wasn't sure how much battery I had left.

Here's where it got weird. I drove to the nearest Co-op to fuel up and could squeeze only 347 liters in. Accounting for the 40-50 liters from the jerry cans and the primer, that still is less than 400 liters (106 gal. US) and suggests my gauge might be accurate after all. I have filled close to 500 liters in the past and the tank should hold 581 liters (130 gal.). A check of the odometer since the last fill (1188 km. or 736 miles) suggests the fuel mileage is about what I would expect (33.3 l./100 km. or 7 mpg US).

So it seems that the symptoms and the cure suggested I was out of fuel, but there had to be plenty in the tank. I still plan to change the filters, since it's time for an oil change anyway, but the bus is running like nothing ever happened and I don't know what just happened.

It's been a weird summer but I'll save the rest for another day.

Don

[belfert]

The dip tubes on most buses don't go to the bottom of the tank.  I ran out of fuel once even though I still had 20 gallons in the tank.

Still, you shouldn't be running out with 3/8ths of a tank left.

[Busn-Gramps]

Hi Don,
Over the years on my MC9 if I get down to about 1/4 tank of fuel and let it set over night it will start right up then run out of fuel.I prime it and it starts right up and I can run like always. I do not have this problem unless I`am well below 1/2 a tank and set over night. I have been told there is a check valve in the fuel line that is bad and lets the fuel drain back into the tank when it is low and just sitting,not running. I very seldom let it get below 1/2

                                                                                                  Paul

[TomC]

My go get fuel time is when the gauge is at 1/2. Good Luck, TomC

[lyndon]

Thanks for the replies and food for thought. I'm a big believer in the "1/2 tank fill" rule during our cold Canadian winters, but we rarely use the bus in cold weather. I worry about the fuel getting too old when it sits in storage for months at a time.

This time, though, I just hadn't got around to fueling up after returning from the trip. We will be more careful in the future, but I guess it's time to install an electric primer pump just in case. I'll look for the check valve, too, if it's not a PITA to change.

[bobofthenorth]

Don't worry about diesel going bad in Canadian winters.  It just doesn't happen.  The only fuel issue you could run into in the winter is if you have summer fuel in the tank and it gels up when you try to use the bus in the winter.  Either wait until October when the stations start blending winter fuel into their tanks or put some Heat or Melt in the tank.  Or don't use it during the winter.

[lyndon]

Good points, Bob. It sure hasn't happened so far. Sometimes I forget it's been 9 winters already because I still feel like a newbie.

Another angle to keeping tanks full would be condensation issues, but we store the bus outside now and the Alberta climate is pretty dry in the winter; I've never seen much water collecting when I've pulled the cork under the tank.

Don

[ol713]

My go get fuel time is when the gauge is at 1/2. Good Luck, TomC

      Yes, I agree.  My "go get fuel" time is about 1/4 of a tank.  Usually start looking
      for fuel when just under 1/2 tank.
                                                 Merle. 

[muldoonman]

Got caught out pulling my Super Crew Ford on I 10 out in West Texas and got mine down to a little over 1/8 of a tank. Running the hills and AC on pulling that brick and stopped at a fuel stop and no pumps a working. Know my prevost will run down That far but never again. At 5 MPG in this 8V92TA, it don't take long to get you in a bind.

[Lin]

Before I installed a fuel gauge I would refill at about 500-600 miles, which is a bit less than half tank.  Now that I have a fuel gauge, I refill at a bit less than half tank, which is 500-600 miles.