Problem putting more than 25 gal into gas tank

[vpearce]

Problem:

We installed new fuel and vapor lines and fuel pumps in the last six months, but when fueling up we can only add a little over 25 gal until the overflow begins and filling automatically stops. Any ideas as to what is happening? Both tanks were empty after the new lines were done.

Background:

We bought the 76 Birchaven in Winlock, WA, Feb 2016 and have been upgrading it ever since, with most of the work done starting in May, 2021. A paper inside a sliding door indicates that this rig may have been in Dade county FL at some point. Otherwise, we don’t know just where it’s been over the years.

I follow the various threads on GMCLIST, the RV guru sites, and have sent questions to Jim K and Nick G of Applied A; Jim Bounds, DJ Eberhart; Jim Hupy. I’ve also talked with the various equipment manufacturers.

Change and Upgrades

Electrical Configuration:

LEDs have replaced the incandescent fixtures and now have 5 batteries - 3 lithium for coach and 2 lead for the engine (Lithium 12v 100 Ah batteries (BattleBorn # BB10012) are being charged by a Progressive Dynamics PD9160ALV 12V converter/charger 60A (will handle 5 lithium batteries) and keeping the Progressive Dynamics PD9270V converter/charger 70A w/ charge wizard for the 2 lead Interstate batteries (GP34 800CA, 1000ca and an Interstate RV 24DC, CCA 550, MCA 700, RC 140) till proven lithium engine batteries become available. The alternator protective cable via E. Fisher has also been installed.

Electrical Upgrades:

We have replaced the original backbone wiring with 0, 1, 2, 4, and 6 gauge:

The buzz box has been replaced with a Progressive Dynamics Power center (12 - DC fused blade and 5 AC circuits) w/ auto-switching;

Victron Energy BMV-712 Smart Battery Monitor w/ Victron temperature sensor and a Victron SmartShunt 500A/50mV (bluetooth) for the lithium;

The Renogy Off Grid 3000W 12VDC to 120VAC Pure sine wave with meter keeps us going when in the boondocks and runs the cell phone connection (weBoost Drive X RV with Verizon), wifi, refrigerator (still have the original);

The solar (Merlin 340w energy kit (2 170W panels) with a Victron SmartSolar MPT 100/50 charge controller w/bluetooth (programed by BattleBorn);

and a Victron Orion-TR Smart 12/12V-30A isolated charger (3-stage charger w/ bluetooth for mixed chemistry (lead & lithium) batteries which are presently installed.

The data console monitors water (waste and fresh), propane, and the Onan 4K generator as well as offers it a remote start.

Safety Upgrades:

Auto fire extinguisher system for engine and refrigeration compartments (Jim B),

Michelin tires with TP and heat monitoring are mounted on AL rims,

Electric wipers with heavier arms and washer,

RAMCO mirrors with signal lights,

Wireless vision of rear and sides (even has a microphone to hear what’s happening behind) along with backup vision,

Brake upgrades include the Albert B’s emergency brake system, master cylinder, proportional valve, rear brake cylinders, drum truing and new bearings with bogie pin greasers.

KYB shocks and front end bushing and bearing upgrades.

Fuel and vapor lines along with fuel pump, tank switching valve and tank filter socks were installed when the tanks were dropped during brake renovation.

Comfort Upgrades:

Maxair vent and a bath vent

Instant water heater

Refrigerator vent

Catalytic heater

Macerator for easier waste removal

External propane connection to system so main tank doesn’t need refilled

Rear ladder

This huge array of renovations has been primarily accomplished in collaboration with our guide and main installer, Todd Lissner (vince.lissner@gmail.com) of ALL Star RV Repair of Sherwood, OR. He’s been amazing!

For now, we need to know what’s happening with the two fuel tanks. At some point in the future, perhaps there will be a GMC upgrade to electrical propulsion. Fossil fuel costs are increasing, and we’d like to be more environmentally friendly, but this GMC RV is timeless!

Virgil
TZE336V100703
Lake Oswego, OR
76 Birchaven w/rear bath, 455, quad-bags, and reaction arm.

 

[Ken B]

It sounds like the vent lines to one or both tanks is blocked or your gauge(s) are off and 25 gallons is all you really had room for.

 

[vpearce]

Ken, thank you - will check that out. I'm headed S to Coburg (about 90 miles) to have the front windshields replaced so a tank gets me there, then will refill and head back.
Then to checking out the vent lines. Certainly makes sense to me

 

[RF_Burns]

Virgil,
I noted you have a Progressive Dynamics PD9160ALV charging your Battle Born Lithium batteries. You should check the manufacture date of your PD9160ALV. Early units were just single stage constant voltage at 14.6 volts power supplies with current limited to 60Amps. Holding the battery voltage at the maximum recommended charge voltage stresses a lithium battery and is not recommended.

Progressive Dynamics upgraded the unit to a 2 stage charge. This is from their website:
Note: Units manufactured after August of 2020 have 2 stages. This applies to the PD9160ALV only. The second stage drops the voltage to 13.6 after The battery is fully charged.

This upgrade applies to all their PD91xxALV models.

If you find you have an early version constant voltage unit, I would contact Progressive Dynamics to get an upgraded unit.

I would check it even if you purchased after August 2020 in case you got one maufacturered earlier. Simply monitor the voltage and watch for the voltage to drop from 14.6 to 13.6 after the batteries are fully charged. For some reason they did not change the model numbers after the upgrade, so how else would you know!

 

[LarryW]

Here is some information about your windshield replacement that I posted the other forum. HTH

There are a number of screws holding the dash in place up against the windshield that are very difficult to get at with the windshield in place. You may not want to remove or do service on that dash right now, but you may want or need to in the future. When the old windshields are out, is a good time to remove those screws one at a time, grease them with a little white lube and put them back in, just tightening them lightly "snug". Because of the angle of attack taking the screws out with the windshields are in place, the screws will come out with relative ease. Believe me, you will thank yourself for doing this. One more thing consider doing is before the windshield is installed, find some kind of sealer for the edge of the windshield. I installed new windshields in 2008 and failed to seal the edges. My windshields are now starting to fog along the edges. Had I sealed them, that wold not be happening. JWID

 

[LarryW]

Another comment from Dave Stragand on the other forum.

"At Mansfield, the installers sealed the edges with DOW Betaprime 5504G."

JFWIW

 

[vpearce]

Virgil,
I noted you have a Progressive Dynamics PD9160ALV charging your Battle Born Lithium batteries. You should check the manufacture date of your PD9160ALV. Early units were just single stage constant voltage at 14.6 volts power supplies with current limited to 60Amps. Holding the battery voltage at the maximum recommended charge voltage stresses a lithium battery and is not recommended.

Progressive Dynamics upgraded the unit to a 2 stage charge. This is from their website:
Note: Units manufactured after August of 2020 have 2 stages. This applies to the PD9160ALV only. The second stage drops the voltage to 13.6 after The battery is fully charged.

This upgrade applies to all their PD91xxALV models.

If you find you have an early version constant voltage unit, I would contact Progressive Dynamics to get an upgraded unit.

I would check it even if you purchased after August 2020 in case you got one maufacturered earlier. Simply monitor the voltage and watch for the voltage to drop from 14.6 to 13.6 after the batteries are fully charged. For some reason they did not change the model numbers after the upgrade, so how else would you know!

Thank you for the info - I'll let you know what I find out - I did get it Nov 18th, 2021 but still, one never knows!

 

[vpearce]

Thank you for the info - I'll let you know what I find out - I did get it Nov 18th, 2021 but still, one never knows!

 

[JSanford]

Fill vent line clogged, pinched or otherwise compromised would be my guess. Could be you pinched the line when installing the tanks. The vapor vent line also provides some pressure relief when filling, so check those lines as well as the vapor separator.

 

[vpearce]

Jeremy - this explains it all as am very visual in my mechanical understanding! Wow! Thank you so much!

This forum is so much better than GMC list! So many restrictions in getting questions on line - Forum just placed my problem on line, and already, I've had replies.

Great, knowledgeable group of members!
Virgil

 

[Matt Colie]

Virgil,
There are some interesting things with the fuel system. These are not real obvious even if you spent as much time as I did trying to make it work.

The picture Jeremy provided will be a great help here.

Problem 1: When you fuel at a typical pump, fuel is delivered at just under 10GPM. That sped plus the dynamic head of the drop from the fill neck mean that fuel is really traveling when it gets to the first tank. So fast in fact that it goes right past and into the main (rear) tank first. This creates the second problem.

Problem 2: Modern motorfuel makes foam when it can. So, when the main tank is anywhere near full, that foam is going out the Fill Vent Line. As soon as any fuel starts going into the auxiliary (front) tank, the venting air pushes the fuel foam in there up to the fill neck to shut off the fill nozzle.

Why this seems to be more of a problem for the 23s than the 26s, just may be the extra space they have.

Want a very successful and inexpensive fix?? (Written up on the old forum as "Recommending High T".)
Just move the T in the fill vent line as high as you can. Under the cab floor has worked well for me for years now. We can take on 45+ gallons of fuel in a 10 minute stop. (Yes, we frequently take on that much - my gauges work and I know the fuel rate.)

Matt

 

[Matt Colie]

Virgil,
If you put the sig that you had in the first post in a sigfile, you won't have to type it in every time.
There will be a V on the upper right near the envelope. Go there and paste it in. VIN is not a big deal, but a name, a bit about the coach and a geo reference are all good.
Matt

 

[vpearce]

Matt - thank you - will get this info to Todd

 

[kidjedi]

Until you have time (and warm weather) to alter the fuel lines... when you fill up, use the second notch on the pump nozzle instead of the (faster) third. It takes a bit longer fill, but forces the "opportunity" to check your oil, do a walk-around, clean the windows, etc. The slower fill rate allows more pressure relief and a greater quantity of fuel to be added. This is what I have been doing with mine until I get a chance to alter the tank set up (currently not the highest item on the list).

 

[vpearce]

Until you have time (and warm weather) to alter the fuel lines... when you fill up, use the second notch on the pump nozzle instead of the (faster) third. It takes a bit longer fill, but forces the "opportunity" to check your oil, do a walk-around, clean the windows, etc. The slower fill rate allows more pressure relief and a greater quantity of fuel to be added. This is what I have been doing with mine until I get a chance to alter the tank set up (currently not the highest item on the list).

Yes - have had the fuel attendant (am in Oregon) do just that! Thanks for the advice - never may know enough!

 

[pdxbirchy]

It does sound like something is clogged. Do you ever get fuel on the ground? That is a different problem.

 

[Bankguy1]

It does sound like something is clogged. Do you ever get fuel on the ground? That is a different problem.

Yes I get fuel peeing out if I try to put more than 25 gal. What’s that problem?
Thank you

 

[Matt Colie]

Bankguy1,
You are relatively new to this forum (that is not a problem at all) and this is your first entry to this thread.
Fuel pees on the ground? Where?
There is a lot that can be wrong with a TZE fuel system, but when it is right, it was well worth the effort.

There is a B by the envelope at the top right, go there and find "Signature". Click on that to put in a sigfile with:
A real name so we know who we are helping and it will be less awkward when we meet.
A short about your coach like year and major mods so we don't waste our time asking questions
A geographic reference because you may have an old friend nearby that you have to meet.

By this time, all the rubber in the fuel system that has not been replaced should be and that is a great place to start. I can tell you how to get the tanks down and back up easily.
Matt

 

[tmsnyder]

Bankguy1,
You are relatively new to this forum (that is not a problem at all) and this is your first entry to this thread.
Fuel pees on the ground? Where?
There is a lot that can be wrong with a TZE fuel system, but when it is right, it was well worth the effort.

There is a B by the envelope at the top right, go there and find "Signature". Click on that to put in a sigfile with:
A real name so we know who we are helping and it will be less awkward when we meet.
A short about your coach like year and major mods so we don't waste our time asking questions
A geographic reference because you may have an old friend nearby that you have to meet.

By this time, all the rubber in the fuel system that has not been replaced should be and that is a great place to start. I can tell you how to get the tanks down and back up easily.
Matt

I was sure you were going to tell him about the 'high-T' mod. I need to do that one as well.

 

[Bankguy1]

Thanks for the info, as soon as I’m done with the waste water tanks, gas tanks next.
Pete