how do you adjust the programing of the controller?
LRA aux tank fill-up observations
- Thread starter prharper
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
Ah, very cool info here. I’ll run this test and see what’s in there.
I believe my pump is programmed for 3 min once the red light comes on.
1st…
I VERY routinrly pump 24+ into my LRA when filling up…so it definitely is capable of sending all 24 to the main.
Couple possible expkanations (theories that are harder to prove)…
After having mine for about twice as long, I’ve become convinced that a full main tank can (perhaps) end up allowing some fuel to find its way back to the empty aux over some time and sloshing…because after emptying the aux, it will sometimes emerge as *one green light* on my small aux tank indicator later, even though I know I’ve emptied it…and sure enough, and all green level indicators were extinguished .
Can’t prove that…so note sure…
2nd thought is— Its RARE that I can dump all 24 from my aux to the main in one go, since its rare that I have a full 24g of space available in the main.
When the main reads E, there are about 4+ gallons in the main…meaning you only have room for 22.
What I am CERTAIN OF, though, it that my 24g aux tanks is very much capable of emptying itself enough to pump 24+ into on many occasions.
Your main though… While you can certainly empty it…You don’t want to do that. So unless you’re on a long highway trip where you can make sure your aux empties, there’s a good chance if won’t have room to fully do so day to day.
I've had my 12.5gal LRA for about a month now. I'd say it's a little tricky to know exactly how much is left in the aux tank. I find the light indicator to be very delayed and inaccurate. I have all stock hardware as far as fittings and pumps go. My usage at this point has been to transfer the entire aux tank when I'm at 1/4 tank on my main. The entire transfer will fill the main to about 3/4 tank. Since the light indicator is delayed I usually just do it until the pump starts making that loud noise which is usually when the aux is empty and just sucking air. I didn't upgrade the pump since my tank is only 12.5gal and it doesn't take too long. I suppose it's probably better than I have the stock noisy pump since that lets me know when the aux is empty rather than relying on the light indicator. So far its been a great addition and the 12.5gal is probably easier to use than the 24 or 40 since I always just transfer the entire aux tank each time.
- Thread starter
- #25
This ^^ same thoughts.
I have a 40 and have never been able to add 40 gallons of fuel to it. 36 or 37 has been my max. Unfortunately, the installer put "some" gas in it to test it out so I never was able to try and fill the bone-dry LRA to get a baseline. I think @nuclearbeef is on to the true reason here. Most gas stations have level fueling pads, but few vehicles are also 100% level. That's assuming level is the optimal position for max fuel fill with an LRA. I wonder too how much of the capacity versus actual fuel is driven by the auto-shut off on most fueling nozzles and a modified filler neck? Further we don't really know if a) the tank was truly empty/dry when we go to fill it and b) if when the pump shuts off if the tank is truly full. Getting confirmation of either would require a good bit of work and knowing the answer wouldn't change anything about how I use it. Maybe someone from LRA can chime in with the definitive answer.
In the end, what I know is that I have a nice reservoir of extra fuel in the car for when I need it. I can always imagine a scenario where an extra 2-4 gallons would be nice to extract (if it's really there at all), but in practice I am never that low.
Its just some effort if you really want to know what's left in the aux tank (drain plug). How important that is to anyone is really up to the anyone. No right or wrong here. My brain is wired in a way that I have to know, so I will find out. I accept and embrace my position on the "spectrum".
I'll look forward to hearing your results.
This time I let the pump run to auto shutoff and then hit it again which turns the pump on again for two minutes the auto shuts off again.
Pretty good.
It looks like I have 2 gal left after first auto shutoff. My need to know is satisfied.
Y’all running that gas pump WFO or on the slow speed? I go slow thinking it will prevent sloshing and help it fill more.
Also, I was assuming we were talking about the LRA pump running after it auto shut off
Also, I was assuming we were talking about the LRA pump running after it auto shut off
I click the gas station pump down to slow when I think is getting close to full.Y’all running that gas pump WFO or on the slow speed? I go slow thinking it will prevent sloshing and help it fill more.
Also, I was assuming we were talking about the LRA pump running after it auto shut off
Yes, we’re talking about running the LRA pump again after the first auto shutoff.
I had to reseal my LRA tank outlet this past weekend due to a seeping gas leak. Before I did the work, I pumped it out with the included facet pump, and when I removed the tank drain and outlet, not a drop came out. So at least on my 12.5 gal, the included pump is capable of pumping it dry.
WFO at my Costco. However, I have noticed some stations are more sensitive than others.Y’all running that gas pump WFO or on the slow speed? I go slow thinking it will prevent sloshing and help it fill more.
Also, I was assuming we were talking about the LRA pump running after it auto shut off
Yes, seems like filling the LRA after the first auto shutoff leaves 5 gallons in the tanks - same as the Toyota low fuel light. When Running it again after it shut off, the pump was louder at times, but I could tell it was grabbing more fuel.
I’ll go WFO on my next fill up and see how it goes. I use the exact same pump at my local filling station for the fat majority of my fill ups so I should get a good ice on consistency.
My LRA pump makes an occasional surge noise regardless of how much fuel is in there but I just assume it’s doing its thing and ignore it. I’ll run it again after it’s initial s*** off and see what it does.
new personal record!
I think @TeCKis300 has actually tested his main tank to empty, but this is as far as I’ve ever pushed it.
Running the pump after the first shut off definitely gets more out of it.
Of the 47.45, 23.8 went into the LRA (first). Then, the rest to the main - WOT into both tanks from Costco pump.
I think @TeCKis300 has actually tested his main tank to empty, but this is as far as I’ve ever pushed it.
Running the pump after the first shut off definitely gets more out of it.
Of the 47.45, 23.8 went into the LRA (first). Then, the rest to the main - WOT into both tanks from Costco pump.
Running the gas pump after it turns off also risks flooding the charcoal canister, so I only do it if I KNOW that the amount that I just pumped in to the tank is significantly less than the indicated volume on the guages. Again, at least on my 12.5, I can run it dry with the stock pumping configuration delivered by LRA - verified recently when removing the fuel outlet and not losing a drop. But note, I ran it several times after it hit the auto cutoff time to be sure.
I think he meant running the LRA transfer pump again after it shuts off. I’ve done that to figure out how much fuel is left in the LRA, which in my case is about 1gal with the first auto shut off.
I agree 100% about the risk with topping off the main tank. Don’t do that.
Here's an interesting tidbit:
I always gas up at the same Costco.
I've been keeping track the last several fill-ups.
Verified LRA 12.5 is empty, filled until auto shut-off, then fill main tank while the LRA settles, then top off aux tank until it clicks off again.
Never takes more than a tenth or so on the top off.
All fill-ups of the aux tank took between 11.3 and 11.8 gallons.
Had to fill up yesterday at a Racetrac station while on the road.
Aux took 12.7 before the first auto shut-off.
Either the Costco pumps are very conservative when counting gallons; or very sensitive to auto shut-off.
I have the same experience, 12.7 at a Super Duper station yesterday; everywhere else is usually just under 12. I question if it is shut off sensitivity of flow volume calibration.