fuel gauge on a mci8

[reelnative]

im wondering if my fuel gauge on the dash is working or just estamating at how much fuel is in the tank, its reading about 1/8 of a tank then will go down to empty, then back to 1/8, I went out to ck the sending unit conns next to were you fill the tank and I could hear what sounded like a pump running or grinding away, it kinda sounded like if there is a pump in there it was half out of fuel, I had the bus running when I did this

is there a pump in the tank and if so was it making this sound because im almost out of fuel, the conns to the sending unit looked good, but I didnt get out my meter to ck them I guess thats next

[gumpy]

What you are hearing is the sound of fuel returning to the tank after it's long travel through the engine fuel system and back. It sounds like a pump running. That's normal.
The fuel is used to cool the fuel system. It draws heat out and carries it back to the tank. There's something like 60% (don't quote me, but it's a large amount)
of the fuel that is sucked up is eventually returned back to the tank.

As for the fuel gauge, get yourself a piece of hardwood dowel and check the level of the tank. Store the dowel next to the tank. Then, never let your fuel gauge
get below 1/4 tank. When your tank gets that low, the fuel sloshes around more. That's why you see it going from 1/8 to empty and back. When you turn right, it will
all run to the other side of the tank, and you will suck in air. In 1/2 mile, your engine will begin to loose power. If you're lucky, it will get through it. If you're not lucky,
it'll die and you'll experience the fun of repriming that big old Detroit.

Don't ever trust the gauge. They are notorious for lying to you. Especially in the last 1/8 of a tank.

[reelnative]

thanks grumpy, I was wondering about sticking the tank, on my 416 cat backhoe that the the way I ck my fuel level, I would of thought they would of put some sort of balleling on the tank so it wouldnt move around like that, so im sure everyone has a stick for there tanks how many usable gals per inch, I herd somewere that theres about 15gal you cant get to in the tank, dont know if its true but im sure someone in here can tell me

[gumpy]

I don't know. I don't use my stick much. I use my gauge     Actually, I've learned over many years that I should fill my tank when it gets between 1/2 and 1/4. Of course, that means
that I usually find a place when it's down around 1/8.  More than once, I've found myself losing power after a hard right-hand turn. 

So, do as I say, not as I do.

As for the last bit, I have 180 gallon capacity. I believe the most I've ever put in is 139 gallons, and I was getting very very nervous before I made it to that fuel stop...

500 miles. That's a good round number. At 500 miles, stop and fill up the bus.

[RJ]

Reel -

Looking at your bus photos, I notice that you've got the aux tank in the front baggage bay, so you're fuel capacity is the same as Gumpy's, officially 179 US gallons.

Of that, only consider 150 gallons as usable, or it's "reprime the engine time."

At 5 mpg, that means you'd better fuel before you hit the 750 mile mark.

The vast majority of commercial charter bus operators insist that their drivers fuel the coach somewhere between the 500 - 600 mile mark on long-distance runs, to avoid revenue loss due to a road call.  Not to mention unhappy passengers!

Craig's advice is wise: 500 miles = time to fuel.  (This is a good guideline even for those with 140 gallon tanks, btw.)

FWIW & HTH. . .

[robertglines1]

brain freeze    I ran out in my previous 8 not a pretty sight...185$ for 15 gal fuel....and 2 hr loss of time

[reelnative]

Hi rj that tank in front of the baggage bay is the aux I thought that was the main tank, were is the main tank then, I thought the fill for the main tank was right next to the entrance door, is there another fill area I dont know about, also if I have an aux tank do I have to switch from the main to use it, and were would the swich be to change over to the aux tank

[gumpy]

Hi rj that tank in front of the baggage bay is the aux I thought that was the main tank, were is the main tank then, I thought the fill for the main tank was right next to the entrance door, is there another fill area I dont know about, also if I have an aux tank do I have to switch from the main to use it, and were would the swich be to change over to the aux tank

I didn't notice the photo, but I'm sure if RJ saw it, he knows what he's looking at.

The main tank is where you fill the fuel, which is right in front of the batteries, and right behind the front wheels.

The aux tank is in the bumpout located in the center rear wall of the front bay. The aux tank is plumbed to the main tank via large pipes located under the bus. Look underneath and you'll
see them running from the front tank to the aux tank. There is also a large pipe located in the front bay that runs along the outside of the tunnel that connects the tops of the tanks together
to vent the aux tank. There is nothing to switch. You fill the main tank, and the aux tank fills. You drain the main tank, and the aux tank drains as well. The level of the aux tank will always be
the same as the main tank, unless you are on a steep hill.

[Busted Knuckle]

"Look underneath and you'll see them running from the front tank to the aux tank."

Some times the original cover is still there and you won't be able to see them, but they are there!

Oh and yes he does have the AUX tank as Guru RJ has pointed out!
  BK 

[belfert]

I would pull the sending unit and see what condition it is in.  I pulled mine and found it was rusted all to heck.  Probably condensation from the bus sitting for a long time without a full tank.

I would look at at a sender from Centroid Products as a replacement with no moving parts.

I also have a brand new universal sender from MCI parts that I will sell for like $5.  It has a 5 hole plae and is generic so it needs to be adjusted for each tank.

[reelnative]

thanks bel ill go look at mine tomm and if I need one ill give ya a shout