8V71 Won't Start

[gus]

Boyce,

Thanks, my concern is the smaller size of my auto pump connections, they are much smaller than the supply line on my bus.

Maybe the one you show has larger tubing, do you know the size?

I'm guessing they have simple rubber flapper check valves and should allow the mechanical engine pump to pull fuel right through.

However, it sure takes a lot more fuel to climb a long grade than to idle. I found that out when I had a small air leak at the gasket of my primary fuel filter!!

[Greg Smith]

Gus
My mechanical pump quit one day. I used an electric pump inline (the type used on automobiles) nothing big and fancy. The bus runs like a dream using just that pump. Maybe this spring I'll fix that mechanical pump.

Greg

[Lin]

The inline electrical pump is a nice backup.  My last bus had an electric pump right at the fuel tank and it worked fine.  However, I once installed one in an old motorhome I had.  I first put it in series, but it did not pass enough fuel to run the engine.  I therefore switched it to parallel.  I would want to be sure that whatever pump I installed had enough passive flow to let the engine run on the mechanical pump alone.

[Greg Smith]

Put a pump in line, hook up a toggle switch, turn it on and GO. You have nothing to lose.


Greg

[rampeyboy]

I too am concerned about the smaller fuel line diameter/flow rate. That is why I pointed out I haven't been on the road with it yet. The lines on the auto pump are 5/16 if memory serves. I had to adapt it to the bus line which I believe is 1/2" I have not been running the electric pump since I got the detroit running. I have been just letting it pull through the electric pump. Seems OK so far.

Boyce

[luvrbus]

5/16 works good you guys as my dad said put the thinking hat on fuel is pumped up and goes out a 0.070 hole on the return line I use the rotary type pump not a impulse cheapo has worked good over the years for me

[Lin]

Clifford, I am not sure I understand what you are saying.  .70 inches would be almost 3/4 inch while 5/16 is just more than a quarter.  Do these pumps give their passive flow through rates?

[luvrbus]

Check it now Lin 0.375 would have been 3/4 I left off a zero in the first post

[Lin]

If you say it will work Clifford, I'm sure it will, but .375 is 3/8" which is still larger than 5/16".

[luvrbus]

I knew that just wanted to keep you on your toes 0.750 is 3/4 I love you guys looking for mistakes I really do

good luck

[Len Silva]

Fortunately, we don't have to look very far

[Lin]

Hey Clifford, I am not looking for mistakes.  I am trying to understand what will work.  I am looking to avoid mistakes.

[gus]

Lin,

Was your MH pump near the tank?

Greg,

  I really like the idea of the electric pump as a backup to the mechanical pump.

Cliff,

Fortunately I paid attention in school during decimals so you don't keep me on my toes, but you do keep me guessing!!

[TedsBUSted]

I'm sort of interested in the flow volume of the mentioned large Auto Zone pump because I always plumb off road equipment with a complicated bypass system and flow-through would make for cleaner and simpler installations.

The crucial data would be knowing the flow volume of the DD fuel pump.
I wonder if the overhaul manual has that spec? I could check sometime.

We know that a 318 can burn a gallon of fuel in three minutes on a hard pull. So the question is how much more flow than .33gpm is needed to assure adequate supply and cooling?

---

[luvrbus]

0.9 gmp fuel spill on a 6v or 8v92 engine Ted fwiw


good luck