2nd Gen Non-Engine/Transmission Fuel Tank Module - loose screws?!

[JGK]

I just got through pulling the module out of the tank with the idea I'd be fixing my fuel gauge sender. It's been reading erratically lately. I think I know what the problem is. The lower half of the module appears to be sliding up and down on the two "arms". The float/sender seems to be OK.



Below are links to 2 pictures in my readers rigs. I'm going to go ahead and re-tighten the screws where it looks like they should be. However, if any one has questions/suggestions, please let me know.



Module:

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Loose screws:

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Thanks,

-Jay

 

[JGK]

Well, module is going back in. Anyone know what the torque spec is on that retaining ring for the module?



Hey, there is 2 fittings on the top of the module. One is called the rollover valve, which has a barb on it but has no tube connected. I can suck air through it but just barely blow air back through (like a leaking check valve). The other one is capped but has a tube on the inside of the module that extends nearly to the bottom of the tank. Is this second one the one most often opened to allow air in as the fuel is used up to avoid a vacuum? I suspect I haven't had a problem since the rollover valve lets a little air through back into the tank.



Thanks,

-Jay

 

[jabird]

I dont have my original out of the truck yet but I have a replacement out of a wrecked truck. The screws were "loose" on this one also. So loose that the red filter screen must have been sitting on the bottom of the fuel tank for some time, by the way its worm away. So what is the normal position for the unit to be positioned on the "arms". Anyone know???? Or are the arms suposed to slide up and down???

 

[CStewart]

Fuel module screws

Just got mine back together yesterday. I had a bad connection on top of the module that I had to fix and the screws that hold the two sections of the module were loose on mine too. I'm gonna try and post pics later but as far as the loose screws I drilled mine out and used 1/4-20 SS bolts and nylok nuts on mine. I also put another hole on the side that only had one screw in it so I have a total of four bolts holding mine together now. As far as how deep to set the module I just measured from the tank flange to the bottom of the tank and the bolted the module together so its about a 1/2" off the bottom of the tank. So far its working great steady 15psi and most importantly no more hard start after its been sitting.



Chris

 

[JGK]

I think Chris has the right approach. Measure from the top of the opening, with the rubber gasket in place, to the bottom of the tank and set the length accordingly. You might set it a little closer to the bottom, like 1/4 inch, given that the bottom of the tank will sag just a bit when filled with fuel. Mine appeared to be originally set at about that depth. The author on one of the "fixit" pages I found on the DodgeRam.org site said he found his were loose and did the same thing to set the length of the module.



When I put mine all back together and started up the truck, I went from just a scoche off empty (red line) to 1/4 tank! Hey, free fuel! I'll fill it up today to see just how accurate the gauge is now reading.



-Jay

 

[TPCDrafting]

JGK, When you state you have erratic fuel gauge readings, do you mean the gauge jumps up and down, as you drive along? Or is it reading differently from one stop to the next?

Mine started jumping up and down from about 3/4 full to E on our trip this past weekend. 3 hours home the guage would jump up and down (including the idiot light and "ding" about every 20-40 seconds. Good thing I had some CD's and had to crank it so I didn't go nuts.

I guess I'm wondering what'll fix mine, if it's time to drop the tank and pull out the whole unit, or if it's just a loose wire somewhere along the line.

 

[dslmacdown]

Tim, sounds like your sending unit in tank is gone or maybe a loose wire. Check the connector to the tank module. If it is the sending unit you can buy it separate from the whole module.



Chris

 

[tractorface]

Uh they are all "loose"

The screws that hold the plastic bottom half to the metal upper half have shoulders on them. The module is supposed to slide. That is part of the overengineered POS we got from DC. As long as you "Tighten" it in the down position I don't see any harm in fixing it in place. Your gauge will read full longer when you do this as well, maybe that is good for the mind Anyway DC designed it to float, my guess is that this was a way to try and keep crap out of the system, not really sure.



-The rollover valve vents the tank and should not be capped.

-The "spare" line is supposed to be capped. Notice the spare line does not go in the module bucket but is kept on the outside of the bucket. Why?

Points to consider

-Why does DC return Hot fuel to the same bucket that the supply line sucks from? I think they are just trying to keep the bucket full. I would rather suck cool fuel and heat it with a fuel heater when it needs to be.

-Look at the bucket "fill valve float" on the botttom of the module. How much fuel can it flow? Put the unit in a 5 gallon bucket and pump fuel out of it. Pay attention to the fuel stream. Does it pulse or is it steady? The valve assembly in the module is easily sucked closed and is a big restriction. If you run a Fass or other aftermarket setup that already has a pre-pump filter on it, than I strongly suggest gutting the valve mess. This will give you unobstructed free flowing fuel. Heck if you are gonna pin the unit down near the bottom of the tank take the fill valve mess off also. The only benefits I see from the VP supply dumping into the bucket are when running up or downhill on a near empty tank and I think it helps keep the screens clear otherwise it just heats up the fuel going to the VP. This might be OK in really cold climates but we NEVER do this on big diesel gensets. We always keep the supply and return seperated by at least one baffle.

Sorry for the long post. Just trying to help. If anyone needs any module parts I am not using mine

 

[DanielH]

I pulled my tank today and found that the strainer had been beating against the bottom of the tank and had a hole in it. I tried to get a new one at the dealer, no luck. I think I like your Idea a lot better just eliminating the module all together. Did you find a store-bought strainer, or make one? If your stock strainer is still good I would like to buy it from you to get me by until I can get the rest of the parts made up. I sure don't want to pay the $450. 00 to the dealer for a new module when all I really need is a strainer

 

[tractorface]

No charge!

I will gladly give you the strainer. Check out the thread below, a member is selling really nice fittings that will allow you to modify your stock module.



https://www.turbodieselregister.com/forums/showthread.php?t=112551



If you run a stock LP and want to strain the fuel before it reaches the pump why not install a strainer in the line external to the tank so it can be cleaned periodically? PM me with your shipping address and I'll mail you my stock strainer. Just to be clear, we are talking about the screen that snaps onto the bottom of the fuel module assembly?!?

 

[JGK]

TPCDrafting,



Sorry for my delay in responding to your questions regarding the erratic fuel gauge readings. I just noticed the new posts, including yours from the 7th.



What I was seeing is that the gauge would read maybe an 8th of a tank lower when I climbed in and started it up from when I last drove it. Then the next time I drove it, it would be back up to where it was before - sometimes even a bit higher. It would stay that way for a few drives, then drop an 8th tank or so again. Like yours when it got to the point that the low fuel warning would come on, it would ding several times while running around town. I finally decided something must be loose and hanging up. Apparently it was this lower part of the module sliding up and down.



Now that it's been fixed for about 4 weeks, it's much more stable. After filling, it comes down off the full mark more quickly than before, but it's consistent as the fuel is used up. As I approach empty, it doesn't drop so fast and shows an 1/8 tank of fuel left for a longer period.



-Jay

 

[TPCDrafting]

Thanks all for the help. I replaced the sending unit yesterday afternoon. I tipped the bed rather than drop the tank. I read somewhere and got advice from others at the last dyno day that this was an easier approach. Especially with my impact gun . Replacing the unit fixed the problem. I did notice the side screws were loose as well on mine. The slots were reamed out where the screws were, I hope tightening them down does the trick. A word of caution, be sure to tip the bed far enough to be able to remove the hole unit without tipping it over I got a lap full of no. 2. Also, wear safety goggles (and work with yer mouth shut) when pulling the fuel lines on top.