Would anyone have the measurements L x W x H of a factory sub tank? Approximate dimensions would help. Thanks
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Thanks! I found one in Oz. I'm trying to get approximate shipping sizes figured out.As you can see, it fits snug near the left/right chassis rails and just behind the crossmember near the springs and just in front of the rear most crossmember. It sits just above the spare tyre cross piece (removed in this picture since I have the spare on the rear).
Too cold and dark to go out and measure it on my 80, sorry
cheers,
george.
What about using the sender from the main tank to determine the fuel level? I am wondering why they put in a separate level sensor for the sub tank system when the main tank already has a fuel level sensor in it?Great question. Theoretically I would think that would work. Just need to be attentive to the level in main tank so you don’t over fill.
Does anyone know what signal is sent from the main tank 75% float switch?
I could make up a circuit that would take the resistance level in from the main tank and at the 1/4 tank level, trigger a continuity signal to the ECU. Pretty simple circuit.From what I recall, the existing sender uses resistance and the ecu is looking for continuity.
I need to do some testing with the factory fuel gage and sensor to see what happens if I tap into that circuit and where it would be best to do that. I need to ensure that I do not cause errors in the main fuel gage reading when the circuit is being referenced. Once I see how that can be done, then it is a pretty simple matter of determining the resistance measurement that corresponds to a 75% full main tank and designing a simple circuit to trigger a solid state switch that would give a continuity signal output that could be used to trigger the OEM system. I do not see any reason why it could not also trigger a relay to run another type of pump. It is just a trigger signal at that point. It would be best if all of this happened in the cab somewhere, as I would not want to design something that lived under the vehicle.@OutlawMike If that type of circuit could be used to shut off a transfer pump like a Holley Blue pump you could most likely market those to members like myself who are running sub tanks without the OEM ECU and transfer pumps set up.
That is the kind of circuit I had in mind to trigger a shut off for a FP relay once the main tank reached 3/4 tank. I was going to include a OEM sub tank switch to turn the pump on.
Was your filler-diverter new at the time of installation?After 11 years of use, I had to do some maintenance...The filler-diverter decided that it no longer wanted to switch over to the subtank.
So, I removed the fender liner, the linkage, and the four bolts on the innards. The pivot had some corrosion, needed TLC with an emery cloth, and some good lubrication. Cleaned everything up, and wow, it works better than 10 years ago. Two items of note; I never had the D-shaped o-ring, thus use FPIG to seal, and I have filled the little rubber boot on the pivot with grease. Hoping this will last another 11 years before needing service again.
View attachment 2663721
Used and about as crusty as it looks now, and it leaked upon the first fill-up...thus my discovery that the o-ring was missing back then. Black FIPG held up fine to gasoline, and now diesel, but in retrospect I could have lubed the pivot assembly / rubber boot.Was your filler-diverter new at the time of installation?
Very slow progress on this. I have a schematic evolving for the control board. After installing my tank (18 gallon tank from Tanks Inc, meant for a 30's Dodge hot rod) I was dealing with the sending unit issue. I bought a translator from Tanks Inc that allows you to translate the input resistance range to the gauge resistance range. That works really well, you can fine tune the output so that the gage reads exactly as you want on E, 1/4, 3/4, and F. That got me thinking that I could put that functionality into the new control board. The control board will measure the resistance from the sub tank and main tank senders. There is averaging on that circuit to cut down on variation due to slosh. I am adding in the translator circuit between both tanks and their gage so that I can fine tune the main tank gauge also. This also allows for reading the main tank resistance level for use in the control board logic circuit. Right now I just push in the momentary switch and hold it until the sub tank is empty (momentary switch grounds the control side of a relay.I need to do some testing with the factory fuel gage and sensor to see what happens if I tap into that circuit and where it would be best to do that. I need to ensure that I do not cause errors in the main fuel gage reading when the circuit is being referenced. Once I see how that can be done, then it is a pretty simple matter of determining the resistance measurement that corresponds to a 75% full main tank and designing a simple circuit to trigger a solid state switch that would give a continuity signal output that could be used to trigger the OEM system. I do not see any reason why it could not also trigger a relay to run another type of pump. It is just a trigger signal at that point. It would be best if all of this happened in the cab somewhere, as I would not want to design something that lived under the vehicle.
Snap a photo without the cap. Is it threads or two notches? There are two version of the filler neck and caps.Hey folks, finally got mine installed. Works great!
Does anyone know if there is a replacement fuel cap (plastic, like normal) that will work on this filler neck? Mine is metal, heavy af, and has a key hole in it. I don't have the key, but it's not locked.
I went to put my HDJ81 cap on it (regular style, plastic) but it fits onto the neck differently, the threads are completely different.
View attachment 2973389
Here is the one I went with before I found an OEM one. Is the neck threaded like the US/Canadian gasser version?Hey folks, finally got mine installed. Works great!
Does anyone know if there is a replacement fuel cap (plastic, like normal) that will work on this filler neck? Mine is metal, heavy af, and has a key hole in it. I don't have the key, but it's not locked.
I went to put my HDJ81 cap on it (regular style, plastic) but it fits onto the neck differently, the threads are completely different.
View attachment 2973389
Based on the locking cap in his photo I'd say no.Here is the one I went with before I found an OEM one. Is the neck threaded like the US/Canadian gasser version?