2nd Gen Non-Engine/Transmission Fuel level indicator failure

[stseeber]

My 99 QC4WD @ 146K My fuel level indicator has taken a %#$@% ... . I never let truck get under half tank due to lift pump weakness... When I fill up it will read full until I get about 50 miles on it and then it bottoms out and light comes on. Code has been set and ck eng light has since gone out. Their are about seven or eight codes relating to this system. Has anyone out their ever had this problem and if you have is it correctible with a computer upgrade or reflash? Truck runs great and I dont really need it but I like everything to be in order.

 

[Ron Bissett]

Originally posted by stseeber

My 99 QC4WD @ 146K My fuel level indicator has taken a %#$@% ... . I never let truck get under half tank due to lift pump weakness... When I fill up it will read full until I get about 50 miles on it and then it bottoms out and light comes on. Code has been set and ck eng light has since gone out. Their are about seven or eight codes relating to this system. Has anyone out their ever had this problem and if you have is it correctible with a computer upgrade or reflash? Truck runs great and I dont really need it but I like everything to be in order.

Have not had this problem but read of others what they did was bang on bottom of tank to unstick float etc . They think this comes from using hi speed truck stop fill hose on full . I use a half speed when filling to keep the possible problem from happening. LOL Ron in Metro Louisville KY

 

[Ncostello]

Didnt a TDR issue mention having about a 1/2 tank and slamming the brakes on real hard to cause a major "slosh" to unstick it?



Worst case would be to remove the bed (not really that hard) and pull out the fuel module. I'm pretty sure Dodge will sell just the level sensor part for replacement. The parts blowup on their computer listed and showed it as a single part number.



The only thing you cant buy by itself is the mesh screen assembly... even though its a seperate part and comes off the module. Dodge makes you buy the whole $440 module for that part.

 

[illflem]

I've bought a couple tank pickup screens separately from the dealer. One had to be replaced because the clips that hold it on broke, the other because I didn't realize that it's easily cleanable. Don't have the part number but remember the price was in the mid 20 dollar range.



The level sender is available for around $35, most dealers have gobs of them on hand since they fail so often.

 

[Ncostello]

There were at least two different types of fuel modules. The one I have is the latest all plastic design. There are no clips that hold my screen system on. It slips on the bottom and the whole screen snaps over the module. Hard to explain really.



my fuel module



These are the photos of my module. Does yours look like this Illflem... just curious cause Dodge would not let me buy it and it kinda made me a little frustrated.

 

[illflem]

Nick, yours is different than mine. What a rip-off if you can't buy it separate. My bet is the same type screen is used in gassers of the same year and might show up on the dealer's parts list.

 

[Ncostello]

I doesn't really bother me now. I just suck fuel straight through the module and it gets filtered by my 30 micron stanadyne fuel water seperator. This way I'll never worry about the screen mesh getting clogged up by anything. That screen is somewhat of a restriction to pull fuel through anyway. Its more like a silk fabric more than a screen.



Did you see my other albums showing my stanadyne filter/lift pump set up illflem?



Basically my fuel module is nothing more than a 3/8" standpipe now. That and a place for the return line to hook to.



I really like what I got now. My pressures never go below 13psi at any point and I usually get small pressure increases when I put the pedal down more. Idle is always a solid 15 1/2 psi.

 

[stseeber]

thanks for reply's But!

What I would like to find out is the sensor a mechanical float arm or what? Why do you think it works for the first 50miles and then quits? I havent pulled the code out yet but according to the code charts their are about 8 codes referring to problems with this unit. . any body ever fix it with a reflash due to circuits having too low or high voltage? Their was a TSB about faulty wiring connectors causing guage failure. .

 

[Ncostello]

On the side of your fuel module there is a small electronic rheostat or something like that. There is an arm made of stiff wire that extends out from this sensor. It pivots on the sensor. On the end of the arm there is a foam rubber like material float. As the float "floats" on the surface of the diesel it raises the arm up and down etc. As the arm moves up and down it moves the contact on the sensor up and down. As to why it would be dropping off after a while I have no idea as the float cannot become saturated and sink. Its solid foam rubber.



All I can think of is that the slide contacts on the sensor is losing contact. I have no idea about the codes.



I'm sorry my pics of the module dont show the right angle for this sensor. I can tell where its at but you cant really see anything that would help you. I should have taken a couple of shots with a good view of this. I wasn't thinking about it at the time.

 

[ftb87]

float or sensor question. My gauge sticks at about 1/4 of a tank. I just drive it till I get about 600 miles... then I fillup again.



I called Dodge and they were not a lot of help (I have 45k on the truck). I asked them what would cause it and they said it would cost about 450 to fix!



In you estimation what would cause the gauge to stick. The $35 part or the $350 part?



Thanks

Frank

 

[Ncostello]

The $35 fuel level part is screwed onto the $350 module part. The fuel level part consists of a sensor, a float arm/float and two wires running up to the plug on the top of the tank. The rest of the module shouldn't have a thing to do with the sensor. Thats how I see it anyway.

 

[klenger]

I wonder if the reostat is open near the full fuel end of it's range. One the fuel drops below the point of the open spot, the computer sees an open sensor and sets a code and the fuel guage reads zero.

 

[Ncostello]

Someone else might chime in but I could be wrong in describing it as a rheostat. I'm no electronics expert but it looks like a mechanical speed control to me anyway.



The electrical contact arm part of it travels in an arc pattern along a series of contact points. So it may not actually be a rheostat. I do remember it cant travel past the first and last contact along the fixed plate.



I may be adding in more confusion... sorry.

 

[CCOLLAR]

I've had a similar problem since about 35K miles, and now have about 105K. Recently, having access to a JD front loader, I pulled the bed off and opened up the fuel tank. This is what I found (the correct electrical terminology escapes me -- please bear with me!):



My problem wasn't the fuel float sticking. It was an open circuit in the rheostat caused by excessive wear on one of the terminals. The rheostat (that the float actuates) consists of two terminals: one terminal, the positive, connects to an arm whose tip passes over a series of electrical traces arranged in an arc. The position of the tip on the arc determines the fuel level. The second terminal, in the shape of a ring underneath the arm, is the ground. A bit of spring metal comes off the arm and touches the ring, thereby completing the circuit. The tip of the spring looks to be just a drop of solder. Well, this tip, over time, wore a path in the ring terminal between what would be 1/4 and 3/4 of a tank. When the arm reached 3/4 (the point where the wear began), the circuit would open and the fuel guage would go to empty. The wear was clearly visable, and I verified it using an Ohm meter.



The fix was simple -- I disassembled the rheostat (required a little finesse), cleaned up the parts with contact cleaner, bent the spring out a little to increase the pressure on the terminal ring, and flipped the terminal ring over so there was no wear path. I then re-assembled the rheostat, connected the wires, checked the fuel guage, re-installed the fuel sender into the tank, slapped the bed on, and was good to go!



Hope this helps.



Craig

 

[stseeber]

Thanks again everyone.

Craig: That was excellant! And it was exactly what I was looking for. My Symptoms are just as you described. . I was thinking if that indicator unit is on top of the tank what do you think of cutting a acsess hole in the bed directley above and then fitting a plate to cover up? Anyone know at what part of the tank it is located? Steve

 

[vciesielski]

fuel gauge

just something to try to see if gauge is working properly. Hold the odometer reset then turn kry to no position. all gauges should go though test for operation of partial and full sweep sould take about a minute.

 

[w-cummins]

Re: Thanks again everyone.

Originally posted by stseeber

I was thinking if that indicator unit is on top of the tank what do you think of cutting a acsess hole in the bed directley above and then fitting a plate to cover up?

That's a GREAT idea and I bet you could use a lid from a 1 gal paint can to cover it up! Then you could make a special wrench too to remove the ring from the sender from the hole in the bed... .

 

[illflem]

Hopefully you won't be having to replace the sender enough to warrant a hole in the bed.

I remove the module with sender by first disconnecting the fuel fill hose and vent, removing the bolts on the drivers side of the bed, loosening the other side then jacking the bed up about 18''. Remove the fuel hose quick connects by squeezing and pulling and disconnect the electrical, remove the ring nut and pull straight up.

 

[Ncostello]

Illflems idea sounds very easy. Just make sure you disconnect the tail light wiring or you'll pull it apart. Might wanna disconnect the fuel fill hoses too. If you cut your bed, it will ruin the value... plus it will take longer to cut a hole and make a decent looking plate than it would to jack up the bed. Just remember the module is about 14" tall... so give yourself some wiggle room under there because you cant pull straight out... the float arm sticks out from the side so you have to pull up then tilt.

 

[CCOLLAR]

No need to cut a hole! Ilflem has a good idea.



Removing the bed is really easy -- remove the bolts, diconnect the electrical (ground straps and tail lights) and remember to disconnect and remove the spare tire "pipe" (the tube that turns the cable winch to lower/raise the spare tire). I didn't remove this, and bent it. Oh well, nothing a little hammering didn't staighten out.



Getting the fuel module out is a little more difficult, if you don't have the right tools. I used a large strap wrench.



Good luck!



Craig