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

[fairmont]

Well, 10 hours ago I started the project. I added a Vulcan Draw Straw, new 3/8 return line from the engine T, and the Tempo fuel level sender. Fuel line and draw straw went smooth, not so much so for the fuel level sender. I'll start from the beginning. I placed one of my new floats (had to buy 10) at the end of the new float arm and scribed a line where it's end lined up on the shaft. The recess in the float is about 9/16", so I backed off 1/2" and cut, then threaded the rod. So far, so good. I hooked up a pump to the suction line going into the factory fuel module from the AirDog and drained the tank. Just a note here, the factory pickup drained practically every bit of fuel from the tank, only bit remaining was soaked up by a towel. Removed all the lines going into the tank, the crossmember between the frame rails, and the two tank mounting straps and dropped the tank. From here I worked on the Draw Straw, I won't go in to detail, but everything went smoothly. Next I noticed that I had a problem. My truck is a '99 and I believe that I have a different tank than Bob. Bob's tank measures 14" at the mounting point for the Tempo gage. My tank measures about 11 3/4" When I inserted the new unit it hit the bottom of the tank and registered about 3/16 tank from empty. At this point I was kinda stuck for ideas, so I did the only thing that came to mind, cut and rethread the rod until the tip of the float was just above the bottom of the tank. Another problem soon surfaced, the shorter you make the shaft, the sooner the float body hits the body of the Tempo unit and prevents it from reading full. #@$%! Another modification, placed two bends in the rod to make an offset to allow the float to clear the tempo body when in the upper range of the tank. Several cuts later I had the gage reading the full range from empty to full. Placed the resistor across the leads of the remote read capsule and hooked up the ohm meter. 27 ohm at full and 227 ohm at empty. At this point I thought all was well. Reversed the steps of removal and got everything back in place. Added back the drained fuel. Two over full 5 gallon cans + a little better than 1/2 of a 5 gallon can, so I'm guessing right around 13-14 gallons of fuel back in the tank. Prime the AirDog and start her up. Here's the disappointing part. Fuel gage registering 5/8 tank. By my calculations, that's more than 1/4 tank higher than it should be. I'm gonna run it for a while and see what happens to the fuel level. I think that 1 option for a fix would be the Tempo unit for a 12" tank, but I REALLY don't want to drop this tank again. I'm cut, bruised, and have fuel in both eyes from trying to disconnect/reconnect the supply, return, filler, and vent lines on the top of the tank. Another thought is adding another resistor the the mix. I'm just too tired right now to try to calculate what I would need to add to make the adjustment I'm looking for. I would like to sincerely thank Bob for doing the leg work on this project and for talking me through the details. I still have some bugs to work out, but without his help I wouldn't have gotten nearly this far.

 

[rweis]

You put the Tempo on the step up just forward of the cannister right?



If you did then we need a huge red flag to make sure we know exactely what happened and what the differences are before anyone else goes forward. Mine is an 02, yours is a 99. We need input that can or have measured in thepast and what the differences are.



Bob Weis

 

[ILIANBG]

It seems there is a big difference between a 99 and 02 tanks. I am getting ready and will be ordering the parts for this project. I will let you guys know what happens. Thank you again Bob for your help.

Ilian

 

[fairmont]

You put the Tempo on the step up just forward of the cannister right?



If you did then we need a huge red flag to make sure we know exactely what happened and what the differences are before anyone else goes forward. Mine is an 02, yours is a 99. We need input that can or have measured in thepast and what the differences are.



Bob Weis

There isn't a step on this tank. There is a flat spot just forward of the canister that has a circle molded in and a flexible lifting handle attached. I cut off the handle and drilled my mounting hole here.

 

[rweis]

Mine (02) has a step. That is the difference. You should have had the 11 3/4" Gauge without the step.



What you measure is the depth of the tank where you are going to place the gauge and get the gauge that is the correct length for that depth of the tank at that location.



So now any one that is going to do this mod needs to know if their tank has the step or not to get the right length of mechanical gauge.



ILIANBG is going to do his '02 which should be the 14" gauge length.



When I had my tank out I measured the depth of the tank at the canister and it was 12" so the 11 3/4" gauge length would have been right for that depth of tank.



You basically want the pivot point of the gauge mid way between the top of the tank and the bottom of the tank (or as close as you can get it) for it to be a correct as possible.



Bob Weis

 

[GAmes]

I've replaced my sender twice, because of bad gauge readings. Both times the float was in great shape. Do those of you that experienced deterioration use fuel additives? If so, what? Maybe there is a clue there.

 

[rweis]

There are a couple of threads addressing the sender problems.



Some of the earlier senders the contact wipers would not stay in contact with the sender unit resistor area and would get intermittent. There are a couple of threads about modifying the pivot arm holding mechanism to try to make the wiper stay in contact with the resistor.



There is a possibility of fouling. There are a couple of articles about bio causing problems with oxidation on copper or brass metals and of course the contact arm and resistor are copper and I think bio will be getting bigger not smaller.



You can always just purchase a new sender mechanism and replace it every couple of years.



I do not know what causes the float to begin to breakup. Some do, some do not. Might be different materials used in different years?, I do not know.



The attempt here was to break the fuel level sender repair cycle permanently. Except I installed mine arse backwards on the first attempt and then corrected that, the "fix" seems to be permanent. There are NO contacts in the tank at all, it is a commercial float, a commercial fuel level sender mechanism, and the contacts to connect it to the OEM system are OUTSIDE of the tank.



I have run it for about 6k, about 15 tanks, and it seems to work perfectly.



Bob Weis

 

[rweis]

FYI UPDATE



As most of you know, when I did this project I mounted the sender backwards at first and then properly the second time. Because of some mounting screw holes that are empty (from the first mount (backwards)) I have gotten a little weeping from that area. When I feel I have a complete solution I do not want ANY outstanding issues.



I found a TDR member with a 02 fuel tank (he purchased one of the aux direct replacement tanks) and I am having that shipped. When it gets here I will change out my tank with the "extra holes" for his tank without the "extra" holes.



I also thought it would be a good time to really document this project with pics and text but I need an idea of where to store it here somewhere on TDR that is not in the thread. Ideas? (and how to get to that storage area etc). I will take measurements and pics at every step to basically create a "how to do it" manual.



I have run the mod for a while and an very satisfied with it to the point I think it is a complete total permanent solution (You MUST know the DEPTH of YOUR tank (apparently the depth of the mounting location changes from year to year)).



Bob Weis

 

[rweis]

Update:



I purchased a used 02 tank because I had mounted my sender backwards and there was some seepage from having too many holes not filled with mounting screws etc.



I wanted to document the fuel level sender replacement in detail and am starting to do so with text and pictures and want to address as wide a series of tank years as possible. The intent is to document it really well and send it in to permanently put in the TDR archives.



I NEED SOME HELP:



I do know what the shape of the 02 fuel tank is, but do not know when its shape changed from what to what meaning:

1. What year did the fuel tank shape of the 02 has start? (probably before 02?)

2. What year did the fuel tank shape of the 02 stop? (maybe it is still the same?)



On tanks of previous years to the 02 shape do they have a place on the tank top body that is flat and could take the relocated fuel level sender?



On tanks of years since the 02 shape do they have a place on the tank top body that is flat and could take the relocated fuel level sender?



Thanks for your help.



Bob Weis



The relocation of the fuel level sender is working fine (9k miles). Low fuel light comes on correctly, dash fuel gauge works fine in its full range and smoothly. I am very very pleased with the modification.

 

[EdwinDavis]

Had to replace the one in my '96 twice.

 

[fairmont]

Bob,

PM sent, feel free to repost any info you feel applies.



Rick

 

[rweis]

Richard Curtis has a 99 and his tank does not have the step up in front of the cannister, but does have a flat spot to mount the reloacated sender just forward of the cannister.



That would mean he needed to measure the depth of the tank at the flat spot just forward of the cannister and get the sender length to closely match the tank depth there (we did not know there were different tank shapes then). The 02 cannister location depth is 12" and IF the tank depth is the same on the 99 then the 11 3/4" sender would be fine.



In the early days of this post I did not realize there were different tank shapes and Richard got the wrong sender length. He is working with it, and we know what the problem is, just very annoying, and for that I appologize.



As emphasized before you MUST measure the tank depth at the location where you are going to relocate the sender to get the correct sender length.



Bob Weis

 

[jjohn]

I coated mine with EPOXY, wasn't eroded to bad on the corners, so why not for an experiment. On my 95 there is a narrow area where the float must go when full, so when reinstalling I had to align the float to this spot. Working good so far.

I seen on a parts web site [maybe NAPA] where they had BRASS floats, but it would have to be soldered, solid no holes for tilting, and maybe a little noisy.

Marv.

So Marv,

Hows that epoxy holding up? Not that you can see it... I have mine apart now.

Thanks JJ

 

[MLee]

JJ;

So far, knock on wood,It seems to be ok. It's a lot of work just to see if it's holding up. Mine rides a long way at the top, 165 pluse miles befor it starts to drop. It must be centered if your tank is like mine. I also put on my version of a vent kit. Its all in the old readers rig section.

I also found a brass float and modified it and it would probably work. I think the reason they are not used is fear of rattle. But you would not be able to hear it any way over the engine.

Marv.

 

[rweis]

Bringing up an old thread -



I am swapping my old tank with the arse backwards install (float swing to the rear) and the 2nd correct install (float swing to the front) into a new (to me) tank (the tank from 10/14 thread) so there is only the correct install (float swing to the front).



Taking LOTS of pics to document the procedure. Should be finished tommorrow.



So far about 25 - 30 OEM tank fulls (~ 12000 miles) with zero fuel level gauge problems.



More to come



Bob Weis

 

[guns101]

Fuel sender and stuff

I dropped my tank 2 times to mess with the sender and related stuff. the next time, I cut a hole in my bed directly over the sender in the tank. no more access problems. what do I care? It's a '97 dodge. put the cut metal back in place and the door is as strong as the rest of the bed. I get tired of screwing around with the poor engineering dodge used to cram my cummins into their truck. the rubber fuel line replacement is enough to discourage just about anybody... lol talk about cuts and bruises...

 

[Signal73]

I dropped my tank 2 times to mess with the sender and related stuff. the next time, I cut a hole in my bed directly over the sender in the tank. no more access problems. what do I care? It's a '97 dodge. put the cut metal back in place and the door is as strong as the rest of the bed. I get tired of screwing around with the poor engineering dodge used to cram my cummins into their truck. the rubber fuel line replacement is enough to discourage just about anybody... lol talk about cuts and bruises...

I have seen the trap door on hinges before it really dosent look too bad can be quite a conversation piece:-laf

 

[Gary - K7GLD]

I have seen the trap door on hinges before it really dosent look too bad can be quite a conversation piece:-laf

One of my past trucks - don't remember which one - had an OEM pop-out access plate above the tank sender/fill area, real easy to service or inspect.



If the specific location to access that area on our trucks isn't right at an under-bed cross brace, shouldn't be that much of chore to cut one in...

 

[cArNiVaLwOrKeR]

Gary, which LUK do you have that will hang with a COMP and 1. 6's?

 

[Gary - K7GLD]

Gary, which LUK do you have that will hang with a COMP and 1. 6's?

ACTUALLY, that's a Comp, and Smarty, and 1. 6's...



I have the LUK Cerametallic, installed it myself - used primarily for towing our 5th wheel - been on for over 4 years and about 25K miles - LOTS of mountain towing, NO problems...



You DID notice my dyno #'s? :-laf