Freightliner fuel gauge, VMSpc tank minder, fueling wedge revisited

[John_Canfield]

While we were sorting our new coach last year, we were trying to figure out the fuel gauge. For a while I was convinced that it was reading low - I would "fill up" and the fuel gauge would read a little over 3/4 full. Then I discovered that the gauge was indeed fairly accurate - at least on the high end of the scale. Problem was that the fuel was foaming so badly that it shut off the fuel pump. Then entered the fueling "wedge" (discussed on a previous thread) which when deployed in the fuel filler handle slowly filled the tank and prevented foaming.

With a great measure of pride I can report that the wedge is a complete success - we have fully filled the tank a number of times. It is filled to the point that I can see the diesel level come up nicely up to the top of the filler neck.

This is the really neat part... I have been using VMSpc for a number of months because I like gadgets and I also like being able to look at what's going on with the engine. VMSpc also had a "tank minder" which reports fuel remaining, distance to go, and mpg. This afternoon at fueling time VMSpc reported that we had 36.5 gallons remaining - I knew that I would need to take on about 60 gallons of fuel. I did my fueling wedge thing and wonder of wonders I managed to cram in 63 gallons of fuel So I now have about a 0.5 gallon resolution of my fuel in the tank. BUT I don't know how much of the fuel in the tank is useable - one thing I learned many years ago while learning to fly was that tank capacity and useable fuel are two completely different animals. I'd be real nervous running the tank down to five or ten gallons remaining.

Lessons: Fill the tank as slowly as possible and consider VMSpc if you want precision fuel reporting.

[John_Canfield]

While we were sorting our new coach last year, we were trying to figure out the fuel gauge. For a while I was convinced that it was reading low - I would "fill up" and the fuel gauge would read a little over 3/4 full. Then I discovered that the gauge was indeed fairly accurate - at least on the high end of the scale. Problem was that the fuel was foaming so badly that it shut off the fuel pump. Then entered the fueling "wedge" (discussed on a previous thread) which when deployed in the fuel filler handle slowly filled the tank and prevented foaming.

With a great measure of pride I can report that the wedge is a complete success - we have fully filled the tank a number of times. It is filled to the point that I can see the diesel level come up nicely up to the top of the filler neck.

This is the really neat part... I have been using VMSpc for a number of months because I like gadgets and I also like being able to look at what's going on with the engine. VMSpc also had a "tank minder" which reports fuel remaining, distance to go, and mpg. This afternoon at fueling time VMSpc reported that we had 36.5 gallons remaining - I knew that I would need to take on about 60 gallons of fuel. I did my fueling wedge thing and wonder of wonders I managed to cram in 63 gallons of fuel So I now have about a 0.5 gallon resolution of my fuel in the tank. BUT I don't know how much of the fuel in the tank is useable - one thing I learned many years ago while learning to fly was that tank capacity and useable fuel are two completely different animals. I'd be real nervous running the tank down to five or ten gallons remaining.

Lessons: Fill the tank as slowly as possible and consider VMSpc if you want precision fuel reporting.

[rebelsbeach]

John, I "tied" this to the "Freightliner Chassis" forum as related content....good stuff!!

[MrTransistor]

Hi John,
The CAT Pocket Tech also reports fuel usage (and a ton of other information). I keep a log of every fill up and record the Pocket Tech fuel usage data. Amazingly accurate! It's just comforting to know that you will be pumping 56 gallons of diesel at $2.42 per gallon. This is the same engine computer data that is accessed on the CAN Bus by the VMSpc.

Problem with Pocket Tech is that it was designed for the older Palms which (take my word on it) you can't find ˜new' any more. They can be had used on eBay but I'm not a fan of buying any electronics item used. When my original Palm 515 got bashed (don't ask), I went nuts finding a replacement. I managed to locate a ˜new' ˜unused' ˜box opened' Tungsten T3 and it works quite well. Second problem is it communicates at a higher baud rate than the Palm 515 so I had to buy a new Pocket Tech adapter also.

According to CAT tech. support, CAT is supposed to start manufacturing their own Palm like device to be compatible with their adapter. Their reason for this is they claim and rightfully so that Palm keeps changing the connector on the Palms and CAT can't afford to keep redesigning their adapters.

I too was a pilot and one of the first things I wanted to know about our coaches was the useable fuel. I filled two 5 gallon fuel cans and ran the tank dry on the second fill up. Used the 10 gallons to get to a station to top off. The Adventurer held 85 gallons useable in a 75 gallon tank. The Journey held 89.5 gallons useable in a 90 gallon tank. I don't know why I've not done this check on our Horizon yet. Probably because of the fuel pick up for the Onan and the fact that the ˜Check Info Ctr.' light comes on at 1/4 tank (Why does that behavior annoy me so much). If you try this check, be aware that diesel engines can be very hard to restart after running out of fuel.

[rebelsbeach]

MArk, I would HIGHLY advise NOT to run your diesel dry....Might be an expensive lesson...

[Cruzer]

My TripTek reports the same thing as the VMS system. It's a handy feature on all of these various engine/trip computers that lets you plan your stops.

I hear you on the not wanting to run the thing too low. It would be nice to be able to do that ONCE to find out but I'd hate to have to deal with refiring it after that. You'd want to park it next to a diesel pump and then run it out of fuel. I've had to bleed lots of construction equipment after running diesels dry and it's not fun. The Cummins isn't that bad but it's much easier to start up a dry system if there's lots of fuel in the tank. A 5 gallon can won't be very much to purge the system with. Best bet is just don't cut it that close. Besides running it real low tends to give you ulcers after a while.

[The Shadow]

I bought a Palm III that works with Pocket Tech last summer and then traded and no longer have use for it. Will let it go reasonable if someone is interested. Cummins had a similar package but it is no longer available for older Palms. I'm now "thinking" Silverleaf.


<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MrTransistor:
Hi John,
The CAT Pocket Tech also reports fuel usage (and a ton of other information). I keep a log of every fill up and record the Pocket Tech fuel usage data. Amazingly accurate! It's just comforting to know that you will be pumping 56 gallons of diesel at $2.42 per gallon. This is the same engine computer data that is accessed on the CAN Bus by the VMSpc.

Problem with Pocket Tech is that it was designed for the older Palms which (take my word on it) you can't find ˜new' any more. They can be had used on eBay but I'm not a fan of buying any electronics item used. When my original Palm 515 got bashed (don't ask), I went nuts finding a replacement. I managed to locate a ˜new' ˜unused' ˜box opened' Tungsten T3 and it works quite well. Second problem is it communicates at a higher baud rate than the Palm 515 so I had to buy a new Pocket Tech adapter also.

According to CAT tech. support, CAT is supposed to start manufacturing their own Palm like device to be compatible with their adapter. Their reason for this is they claim and rightfully so that Palm keeps changing the connector on the Palms and CAT can't afford to keep redesigning their adapters.

I too was a pilot and one of the first things I wanted to know about our coaches was the useable fuel. I filled two 5 gallon fuel cans and ran the tank dry on the second fill up. Used the 10 gallons to get to a station to top off. The Adventurer held 85 gallons useable in a 75 gallon tank. The Journey held 89.5 gallons useable in a 90 gallon tank. I don't know why I've not done this check on our Horizon yet. Probably because of the fuel pick up for the Onan and the fact that the ˜Check Info Ctr.' light comes on at 1/4 tank (Why does that behavior annoy me so much). If you try this check, be aware that diesel engines can be very hard to restart after running out of fuel. </div></BLOCKQUOTE>

[John_Canfield]

We just had the Horizon for three or four weeks when I managed to run the generator dry - right at about 1/4 of a tank (we were right in the middle of summer and we were running the basement AC and dash air.) Then I had a little more of a clue about the accuracy of the fuel gauge .

Fortunately we were close to a truck stop so we filled up and pulled forward; Jane went inside to pay and I tried to start the genny. When it was cranking it sounded like it was going to literally fly apart in three thousand pieces. It was knocking, banging and clanking. Never heard such a racket; I had to prime the diesel a few times on the boat we used to have and it never sounded like this.

Anyway after several iterations of cranking and banging start attempts (about five seconds per attempt), it finally came slowly to life. I was certain the engine was damaged, but all was well

Bob - thanks for cross posting...

Mark - I have heard about using a Palm device for presenting the data from the OBDII - I prefer the larger display of the laptop, but whatever works for you is the right solution

[Gary Krieg]

OK, is did a search for the fueling wedge discussion with no success. Can someone direct me to that discussion thread.

Gary

[Dougmyers]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Gary Krieg:
OK, is did a search for the fueling wedge discussion with no success. Can someone direct me to that discussion thread.

Gary </div></BLOCKQUOTE>
==========================================

I think this link will get you there?

The "wedge" - pictures

[rebelsbeach]

Isn't it true that the generator shutting down when the coach fuel level is at 1/4 is by design,to prevent you running the fuel out with just the generator?

I'd look it up, but my manuals are at the dealer...IN THE COACH!!

[rebelsbeach]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dougmyers:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Gary Krieg:
OK, is did a search for the fueling wedge discussion with no success. Can someone direct me to that discussion thread.

Gary </div></BLOCKQUOTE>
==========================================

I think this link will get you there?

The "wedge" - pictures </div></BLOCKQUOTE>

Doug...here's a few pics too....

[MrTransistor]

Hi John,
I have found that if you run the coach to below 1/4 tank, the fuel actually siphons from the Onan's fuel line making it occasionally hard to start or it will die after starting. If you press and hold the Onan ˜Stop' button, it will run the generators fuel pump and recharge the line with fuel after you fill up. This has worked fine for us. About 60 seconds does it.

And rebels beach,
Yes in deed, the fuel pickup for the Onan is positioned to run dry at the 1/4 tank level. The reasoning is so you won't run the tank dry when boon docking. I suppose that if someone was not paying any attention to fuel management, this might save a call for a tow truck to bring fuel. Since I keep very close track of the fuel status I just find it annoying. That 25 gallons you can't access would run the Onan for 50 hours at half power (.5 gallons per hour). We actually average around .3 gallons per hour to run the Onan.

What kind of expensive lesson? This procedure worked just fine with the CAT 3126 in the Journey. The C7 is virtually identical (a bit higher injector oil pump pressure). I've never heard of any damage to either the injectors or controllers from fuel starvation, only dirty fuel that manages to get past the (3?) micron particulate filter that CAT uses. Please let us know if you know of any issues with regard to running out of fuel on either the Cummins or CAT engines.

The alternative to find out exactly how much useable fuel the tank holds would be to disconnect the line from the tank, hock up a pump (I don't think there is a fuel pump in the tank), and suck it dry. I'm reluctant to do this since at a little under a quarter tank you would need to catch around 20 to 25 gallons of diesel. Seems easier to carry two 5 gallon cans. With the Journey, we always carried the 10 extra gallons since I would run it to near empty quit frequently, but never did run it dry. I did put 86.5 gallons in once with a known tank size of 89.5. The most we've ever put into the Horizon was 90.2.

[John_Canfield]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MrTransistor:
Hi John,
I have found that if you run the coach to below 1/4 tank, the fuel actually siphons from the Onan's fuel line making it occasionally hard to start or it will die after starting. If you press and hold the Onan ˜Stop' button, it will run the generators fuel pump and recharge the line with fuel after you fill up. This has worked fine for us. About 60 seconds does it. </div></BLOCKQUOTE>Mark - wow, that's a great tip. I'll file that away in my (hopefully) non-volatile biological computer

I have thought about carrying three diesel jugs with me for emergency fuel but I just didn't have the room. What I really wanted when we went coach shopping was a 150 gallon tank - but everything is a compromise.