2nd Gen Non-Engine/Transmission Fuel Tank Float - How many of us had to change it because it deteriorated?

[rweis]

Well, no input from ya'll for 2 days, so this is the way I am going and why.



Because I think B## (biofuel) is only going to grow, and if it does not then the tank indicator solution will still work, and if it does the tank indicator will still work.



I am going to go with the Tempo mechanical gauge with remote reading capsule.



Why:



1. Zero electronics in the tank. No copper wires, no copper resistor board, no contact zone to wear. Strickly mechanical gears. If the statement about bio and copper, brass, bronze is right, then it is ok, if the statement is wrong, still ok.



2. No DC components except the canister to physically hold the DrawStraw top and bottom. Not reliant on DC for anything except the frame which I also made non sliding and screwed down to a fixed height.



3. No copper float, no brass attachments, no brass arms. IF (IF) the posted comments about copper / brass does create a partical problem with B## I am not going to aggravate it for myself. If they are wrong, I still have not caused myself my own problem.



4. No modifications of a Stewart Warner parts (rheostat) to mount on the DC canister. No adapters, no "engineering", no "well, that has to be good enough". No bending float arms so see if they will fit. The manufactured parts are basically unchanged (with the exception of changing the float) and will do what they are designed to do with proven technology over many years.



5. Out of the box installation (with the exception of the float).



6. The sensor is mounted outside of the tank and is designed to be done that way. IF it breaks, it can be changed without opening the tank. The sensor has 2 wires, it does not assume a ground (comes with spade lugs already connected). The DC connector has 2 wires, and puting a mating spade receiver on the OEM wires should be all that is necessary (have to solder on the parallel 2700 ohm resistor across the spade lugs so the 20 - 220 ohm DC system will work with the 35 - 240 ohm industry standard system. The OEM gauge error will read not more than 1/16 lower than actual until 1/2 tank then virtually accurate until empty).



7. Mounting flanges and seals are commercially made for fuel (including diesel) and orderable and replaceable and standard 5 screw design. Structure of the flange is 1/8" steel and made for the purpose of mounting the gauge to a fuel tank just like I am doing. A boat has at least as much (if not more so) movement than our trucks have as far as mounting security.



8. Parts can easily be ordered by the internet or any boat store and shipped from in stock. The Stewart Warner parts were suppose to take 2 weeks, then 2 weeks more, then ???.



What I ordered:

BoatFix.com:

Tempo 420040 (11 3/4" tank depth) mechanical fuel level gauge. I measured the tank at the moulded mounting place is 15" deep. We want 3" of fuel remaining when the gauge reads "empty" to insure the DrawStraw stays covered. That gives us 15" - 3" = 12" for the gauge. The closest one they make is a 11 3/4" gauge. Being a little shorter also gives us a little more fuel depth when the "Low Fuel: mil light goes off at 1/8th tank (1/8th of 24 gallons = 3 gallons more, which I think is about 3/4" more depth at that place in the verticle shape of the tank) which should give 3 3/4" fuel depth on level ground. You can adjust your own refuel level depending on your confort zone and terrain. $46. 24



Tempo 420001 remote reading capsule. This screws onto the mechanical gauge frame in place of the mechanical gauge face and is the 35 - 240 ohm rheostat that sends the variable voltage to the PCM to develop into a bus signal for the OEM gauge. $35. 82



The mechanical gauge works this way. The float is on an arm that rotates across an arc vertically. The frame end of the float arm is a gear that meshes with a gear attached to a vertical shaft inside the vertical gauge frame housing (sort of like beveled gears). At the top of the vertical frame there is a magnet attached to the vertical rotating shaft. The head of the gauge is sealed. If you use the direct reading capsule that screws onto the outside of the head the dial pointer just follows the magnet and has tank level markings on the capsule. If you use the remote reading capsule then there is a module mounted on the capsule that reads the position of the magnet mounted on the vertical shaft inside the gauge frame and translates that into variable resistance.



Stewart Warner

Installation Kit 366LP-F for tank mounting. 1 flange, 1 gasket (72030), 5 washers, 5 screws from local auto parts supplier. Came in about 3 days. I think about $20.



Float:

RobertMfg.com Poly float PF26 Cylindrical 1. 5: dia, 3. 75" length, 3. 26 oz bouyancy, . 73 oz weight. Threads on a 6/32 OR 8/32 male thread. I cut the 420040 mechanical float arm 3 3/8 " shorter, threaded 3/8" of 8/32 male threads on the aluminum arm. Screwed the float onto the arm. $2. 50@ see next comments.



I had to order 8 of them ($20 min cc order, + $15 cc handling) and I am going to use 2 (1 for OEM tank, 1 for bed aux tank) and keep 1 for a spare. So I have 5 to sell if anyone goes this route ($2. 50@ + shipping).



So there you have it, my approach. I should have it installed in 2 weeks.



Bob Weis



Note: Talking with Tom (parts guy) about the copper, brass potential problem he commented "can you imagine how many stationary & agricultural diesels there out there with copper fuel tank lines, or butyl or nitryl O rings in the fuel system. This could be a really huge problem to going biodiesel"

 

[ILIANBG]

Bob, I really appreciate what you've done and I would like your help to build the same for my truck. Please consider me, for two of the extra floats, that you had to buy. I want them. I am tired of dealing with this OEM "piece of art". Great, can't wait to solve it. Sorry for the absence . We just moved to our first house, so it's really hactic still.

Ilian

 

[rweis]

Ilian - You have 2 of the floats from Robert Manufacturing.



House moving certainly is hectic, I do not envy you. Lots of honeydo's too.



I will take good pics to document this. I have tried to think of every possibility to "fix" the OEM, "modify" the OEM but it becomes just that, a patch. That is why I think a total replacement of the fuel level sender system (to a mechanical system because of the warning about biodiesel) not using any DC except the gauge and wire harness.



Bob Weis

 

[MLee]

Bob;

I've read where brass and diesel is not compatable, with no expaination of what it does, The MSDS that I read, said that it discolored it, but did not give any further info. Does it cause a build up of deposits like aluminium gets on it if not keeped clean through oxidation? Just wondering. How about coating the brass float with Epoxy like I did on my stock original float?

Bob you have done alot on this research and are to be complimented on your efforts.

Marv.

 

[ILIANBG]

Yes Bob, thanks for all the work you've done for us, we all will benefit from it.

Yes, moving is hectic, still boxes to unpack... I am eager to see pics when you are done. Thanks for counting me in. Let me know when you get the parts.

Ilian

 

[guns101]

had to replace mine 4 years ago. edges were split,float sunk. what joy.

 

[kscheffler]

I just installed the same guage in a new tank in my boat. Why don't you use the float that comes with the tempo guage?

 

[rweis]

I took the Tempo float off the arm and cut the Tempo float in half a week ago and put it in a jar of diesel fuel.



Guess what is SINKING?



On day 1 both halves (cut side down) floated right on top of the diesel.



A week later both halves (cut side down) are at the 1/3 way to fully submerged point.



I think it is CRITICAL to the "compressed coke" type float that the outer compresed skin is not disrupted to remain fully floatable. No rubbing on tank walls, no mechanical interfearance, no "too loose" on the arm.



I am changing to a diesel rated poly float.



Bob Weis

 

[rweis]

First part of the exchange -



Will the DC system (20 ohms - 220 ohms) read the 35 - 240 ohm range correctly with the parallel resistor of 2700 ohms? Pretty close. 2740 ohm (what my resistor actually reads) gives 26. 4 ohms to 226 ohms.



I built a spreadsheet to see what the fractional error is. Generally will read less than 1/8th error (too low) when full, to about zero error when empty.



Now I know the DC gauge will probably function. I will empty the tank and drop it and install the mechanical gauge with the remote reading capsule.



I did not want to get into emptying the tank and dropping it if the DC gauge would not read correctly (or about so).



Bob Weis

 

[Froadin]

I certainly appreciate the work you are doing on this.
My gauge works occasionally, and I know my float is in pretty bad shape from when I put my draw straw in.
Ok, where will this mount at? On top near the fuel module?

I run Bdiesel now and again, sometimes straight B99, so this is a concern for me.

Keep up the great work, and take plenty of pictures!

 

[ProspectorTim]

Hey guys why not switch to something like one of these
http://shopping.rexmar.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=centroid
No float to deal with. A fellow TDR memeber turned me on to them. He is going to get me the details but it would be easy to contact Centroid directly and get one. He did tell me that centroid set one up to have the same voltages needed for our trucks.

Here is the companies actual website... http://www.centroidproducts.com/

JR2, You've got MY attention.
The more I look at that, the more I wonder - Why bother with a float at all?

 

[Froadin]

Those look pretty slick.
But the depth of them is a bit off from what we need.
Then there is mounting them.

 

[ProspectorTim]

The depth can be adjusted and re-calibrated.
What depth ARE we dealing with?

Then there is the mounting... .

 

[Gary - K7GLD]

GARY - Any ideas on a resistance circuit to subtract a resistance value over a range of resistance? ie 35 - 240 ohms -> 20 - 220 ohms?

I just now started reading this thread - as to a bridge resistance to do what you suggest, might be a bit involved - bridging a fixed resistance is easy - but a variable one considerably harder to do while maintaining accuracy across the whole range... The 2700 ohm value mention as a single element bridge favors accuracy at the lowest extreme, but sacrifices accuracy at the high resistance side, just as you already found out.



My question is, has the composition or part # for the tank floats changed in later years - are the later trucks like my '02 likely to be exempt? My gauge seems as steady and accurate as ever, and Bob mentions his appears OK as far as can be determined from external appearances - have the owners of later 2nd generation trucks lucked out - and if not, is there anything from the 3rd generation stuff that might be adapted - assuming they don't have the same issues... ?

 

[Froadin]

The depth can be adjusted and re-calibrated.

What depth ARE we dealing with?



Then there is the mounting... .

As for depth. .

I measured the tank at the moulded mounting place is 15" deep. We want 3" of fuel remaining when the gauge reads "empty" to insure the DrawStraw stays covered. That gives us 15" - 3" = 12" for the gauge.

S I guess we could say that the first one on the link you provided would be dead on with a 3" to 12" depth. Depending on the mount that is.

 

[Gary - K7GLD]

Notice in the list: Also, copper, bronze, brass, tin, lead and zinc can cause deposit formations. The use of these materials and coatings must be avoided for fuel tanks and fuel lines. "

And yet, Bosch HAS used brass inside the VP-44 - and Carter uses it in LP pump bushings... :-laf

 

[DerekW]

I have to be careful about how much fuel is remaining at the "low fuel" light, because I can not have the draw straw ever become uncovered.

air in fuel is bad, but you also need a good capacity of fuel remaining in the tank so that it doesnt get hot as fast. if it gets hot you loss power and it runs like a diesel without a turbo. this can be dangerous when you used to having this much power while towing then all the sudden you have half that number. talk about getting run over merging on to freeway

 

[Froadin]

http://airstuff.com/eshop/10Expand.asp?ProductCode=FP

Another sender, aircraft based.
Among many things to choose from, you can have any length you want, even have a mounting kit for plastic tanks, etc.

And is 3" fuel depth really the minimum we need for a draw straw? Is that to keep it submerged while at angles?

 

[rweis]

This post is going to be LONG, subject is installing the Tempo mechanical gauge with the remote reading capsule and paralleling a resistor to make the referance points compatiable to DC PCM bus inputs.



Bad news is today was grand daughter's elementary school graduation and my wife took the camera so no pics.



The Tempo 11 1/2" mechanical gauge and remote reading capsule came yesterday. I got the 2700 ohm resistor to test the parallel readings would be in the 20 - 220 range. The resistor was 2740 ohms and the readings were 26 - 226. Close enough. More accuracy on the empty end of the range.



Last night I leveled the truck with 2x4 boards because I was going to siphon the Draw Straw to empty and see exactely where it sat. The diagional cut of the bottom of the Draw Straw upper hole sits 1/4" off the bottom. I siphoned the tank totally and then dropped it and measured what was left in inches. So we know that however you cut the Draw Straw it will do exactely what you cut it for (it's mechanical so it SHOULD, but I still wanted to verify).



I dropped the tank and took out the OEM level rheostat and associated wiring. The Canister now only houses the functionality of the DrawStraw and the roll over valve. The capped off little port and the electrical connector body are still in the canister top taking up space.



I marked the opening for the Tempo and cut it. Also pre drilled the holes so screws would thread into the body of the tank.



I soldered the spade connectors of the remote reading capsule rather than accept the crimp connection.



When I removed the black float from the Tempo gauge last night I mis-measured the arm length. However it turned out to not be a bad thing. I cut the arm too short. and threaded it for the float. I could not find a 8-32 coupler at Lowe's or HomeDept so I bought aluminum 3/8" rod and made my own coupler about 1" long. I added more length to the arm and was ready for today.



I put my emphasis on the float to be accurate at the empty end of the range. I need to emphasize that.



What made the arm cut wrong was I forgot to check where the float floats in fluid. It is not at the far tip of the float. The float sit in about 1" of fluid before it floats. Keep that in mind.



I pulled the canister , took off the rheostat and wiring and ground the nylon slider finger down smooth to the shape of the canister (yes I am dangerous with a Dremel). When trying to get the canister apart, one finger would lock when I had freed the other 2 fingers. Over and over and over the frustration grew. I had already put 2 screws in the canister so it would not slide up and down and would hold the DrawStraw firmly and exactely. I had already taken the bottom screen filter off the canister, and set the bottom of the canister so the DrawStraw protrudes out the bottom of the canister about 1" directly into the bottom of the tank with no protection from debris (the first item in the fuel system after the Draw Straw is a RACOR 690T water seperator / filter). Firm mounting to the lower end of the DrawStraw, yet the DrawStraw metal top mounting can rotate because of the truck bed frame member makes it really hard to screw on AN-6 fittings once the tank is fully installed but if you rotate the Draw Straw head a little bit it in the verticle axis it makes it easier to get the AN-6 fitting on (I use a crow's foot 11/16, but it is still slow going).



Ok, the canister is finally done, no fuel level sender, no copper wires anywhere in the tank. Just the DrawStraw.



I mounted the Tempo on the ledge just forward of the canister. The tank seems to be made of 2 different bonded materials. The outer one is a black resin type material and the inner one is a grey smooth very dense material. each is about 1/8" thick.



Remember I had to make a 8-32 coupler? Well the Poly Float has a mating ridge on it that requires the center mounting hole to be bigger than necessary. Well just unscrew the coupling and take the float off and make the mounting hole the smallest diameter you can (exact fit for the gauge frame). Also in the literature that came with the gauge it tells you the mounting holes only line up correctly ONE way with the gasket. I found that the arm length (reconnected) will clear the canister with the arc that faces the canister. If you do not like the arm swing later, because the coupler allows you to make changes, you can easily change it.



The mounting rise is about 1" higher than the canister. I set my float arm so that I get Empty when there is about 3" of fuel remaining. The DC PCM "low fuel" should still come on at 1/8th tank so that should add about 3 gallons to the about 3" that will be in the tank when "empty" so the DrawStraw NEVER becomes uncovered (ie create your own sump to the depth you are comfortable with it. I am getting a 55 gallon aux bed tank so I am willing to have a deeper "sump" than maybe you are. )



I used Grey "form a gasket" RTV to be sure the mounting is sealed. I also used longer 10-24 screws and put small fender washers (ie small hole (#10) large diameter) and 10-24 nylock nuts on the tank side of the mounting to be sure the mount stays put.



Only the center two wires of the tank electrical connector are active. I added 2 long wires from the OEM harness to connect to the remote reading capsule so I can lower the tank totally to the ground and not strain the gauge wiring.



The biggest battle is of course the filler hose and vent hose. No room, hard to get yout hand with a tool to get those connections tight, but you have to do it like it or not.



Ok, put the siphoned fuel back in (about 15 gallons) the OEM gauge read one needle width above empty. Went to totally fillup, took 21. 5 gallons. Low fuel light use to come on at about 24 gallon fillup. I think EMPTY on the OEM gauge is going to be about 24 gallons to the fill. I have to see how that is going to go. Remember I want safety for the DrawStraw and accuracy at the lower tank levels. E = 24 gallons is fine. However the full fill only reads 5/8 full. I think it might be because of the 1" higher platform the mechanical gauge sits at. Not sure. The DTE has been continually reading 394 miles. I drove 40 miles (after fill up) and the DTE still reads 394 and the OEM gauge = 5/8 full. I just have to see where this goes with the gauge. I thought (what I get for thinking) that the "full" would be more 3/4 OEM gauge mainly because of the 4" fuel when it reads EMPTY and the 1" higher mounting platform.



So I now have a mechanical remote reading gauge, with a parallel resistor to get within DC parameters and a poly float certified for diesel.



Oh, I really closely checked my OEM float and it does have places the hard pressed type surface has rubbed off to the porus material. The Tempo float of the same material that I cut in half is still taking on fuel into the porus material of the float.



I think I am glad I did this, never really can be sure.



I like the idea of No copper, brass, etc and should be bio fuel safe as far as the tank is concerned.



I like the idea of the poly float diesel rated and get rid of the composite float.



I like the idea of getting the DC rheostat out of the tank and get rid of that potential problem (I do not ever plan to go back into the tank for maintenance).



I like the idea that the gauge wiring is now soldered solidly to the OEM harness. I thought the FULL gauge reading would be close to 3/4 full, 7/8 full or FUll, not so. Same amount of fuel, just take some getting use to where the DC gauge reads now. If I felt I needed to change the parallel 2700 ohm resistor I can as it is mounted outside of the tank.



Bob Weis

 

[Froadin]

I like the accuracy at the low levels. With a draw straw myself, I am keen on knowing that myself.
On the other hand, I can't have the incorrect readings for full as my wife and other family members occasionally drive my truck. I don't want/need them to learn the different curve to the fuel gauge. I wouldn't have a problem with this, but my wife thinks it's rediculus. Oh well.

Still, I would love to see pictures of this setup, and mainly how you mounted it!