fuel level unit
#1
Registered User
Thread Starter
fuel level unit
My fuel gauge quit working, always shows full. and I noticed the ground strap between the cab and bed is broken, no ground. Without this ground strap attached, how is the fuel level grounded?
kerley
kerley
#2
Registered User
Ground strap between bed and cab is there to reduce radio interference and improve radio reception.
Fuel level sensor does not use chassis ground (fuel tank is plastic) it uses a variable resistor with a return to the gauge instead.
Always full indicates a short circuit. (if the needle droops to zero with the ignition off, if it stays up you look into a gauge cluster problem)
Fuel level sensor does not use chassis ground (fuel tank is plastic) it uses a variable resistor with a return to the gauge instead.
Always full indicates a short circuit. (if the needle droops to zero with the ignition off, if it stays up you look into a gauge cluster problem)
The following users liked this post:
Kerley (02-13-2018)
#3
Registered User
Thread Starter
Fuel Gauge
AlpineRAM, thank you for your reply.
When my ignition key is off, the fuel gauge shows empty.
When the ignition key is on, the fuel gauge shows full, regardless of the amount of fuel in the tank.
Would my situation suggest that the fuel level in-tank float is faulty?
Thank you
When my ignition key is off, the fuel gauge shows empty.
When the ignition key is on, the fuel gauge shows full, regardless of the amount of fuel in the tank.
Would my situation suggest that the fuel level in-tank float is faulty?
Thank you
#4
Registered User
A bad float usually sinks, not float higher. Sounds like a bad sender or wire issue.....Alpine is most likely correct in diagnosing a gauge problem.
Have you had the dash apart recently?
Have you had the dash apart recently?
The following users liked this post:
Kerley (02-14-2018)
#5
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Thread Starter
#6
Registered User
The sender is in the fuel tank, you will either lift the bed or drop the tank.
There is a big white ring on the tank, unscrew that, and lift out the fuel tank module (disconnect the cables and hoses first)
The float has an arm that moves a potentiometer, and sometimes the axle gets stuck, or the potentiometer gets worn out.
If you don't need the truck right now- disassemble the tank and take a look, take pictures and post them.
There is a big white ring on the tank, unscrew that, and lift out the fuel tank module (disconnect the cables and hoses first)
The float has an arm that moves a potentiometer, and sometimes the axle gets stuck, or the potentiometer gets worn out.
If you don't need the truck right now- disassemble the tank and take a look, take pictures and post them.
#7
Registered User
The sender is in the tank and is part of the or at least the float mechanism attaches to it. You either need to raise the bed or drop the tank to get to it by removing the 6 or 8 inch diameter locking ring then the fuel module will lift out and the sender is part way down on the outside of the module cant miss it since the float is attached to it. Personally I dropped the tank as I could do that myself without to much hassle though either get all the fuel out or run it very very low like down to E. Even 5 gallons of fuel in there sloshing around while you are trying to get it back up makes it quite a bit harder due to the additional weight but more was the sloshing around. You can stick your head up between the bed panel and the frame and see the top of the tank and wires coming out of it, follow them back as far as you can to look for chafing, break, bare wire etc not all that far if I recall before it goes out of sight or into a bigger harness and then out of sight if I remember right. Beyond that point I do not know where it goes. Do know that the plug it comes out of is a 4 wire plug but only two wires go to the tank the other two are not there/ or not missing they are not used in the diesel application.
Looks like Alpine ram posted same while I was typing
Looks like Alpine ram posted same while I was typing
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#8
Registered User
Thread Starter
The sender is in the fuel tank, you will either lift the bed or drop the tank.
There is a big white ring on the tank, unscrew that, and lift out the fuel tank module (disconnect the cables and hoses first)
The float has an arm that moves a potentiometer, and sometimes the axle gets stuck, or the potentiometer gets worn out.
If you don't need the truck right now- disassemble the tank and take a look, take pictures and post them.
There is a big white ring on the tank, unscrew that, and lift out the fuel tank module (disconnect the cables and hoses first)
The float has an arm that moves a potentiometer, and sometimes the axle gets stuck, or the potentiometer gets worn out.
If you don't need the truck right now- disassemble the tank and take a look, take pictures and post them.
Kerley.
#9
Registered User
Thread Starter
Fuel Level
The sender is in the tank and is part of the or at least the float mechanism attaches to it. You either need to raise the bed or drop the tank to get to it by removing the 6 or 8 inch diameter locking ring then the fuel module will lift out and the sender is part way down on the outside of the module cant miss it since the float is attached to it. Personally I dropped the tank as I could do that myself without to much hassle though either get all the fuel out or run it very very low like down to E. Even 5 gallons of fuel in there sloshing around while you are trying to get it back up makes it quite a bit harder due to the additional weight but more was the sloshing around. You can stick your head up between the bed panel and the frame and see the top of the tank and wires coming out of it, follow them back as far as you can to look for chafing, break, bare wire etc not all that far if I recall before it goes out of sight or into a bigger harness and then out of sight if I remember right. Beyond that point I do not know where it goes. Do know that the plug it comes out of is a 4 wire plug but only two wires go to the tank the other two are not there/ or not missing they are not used in the diesel application.
Looks like Alpine ram posted same while I was typing
Looks like Alpine ram posted same while I was typing
#10
Registered User
The system works like this:
Switched power goes through the sender , from the sender to the gauge, and then to ground..
The less fuel there is in the tank, the higher the resistance of the sender, therefore less power to lift the gauge needle.
An "always full tank" therefore means that you have a short circuit somewhere, I'd start by disconnecting the electrical connector on the tank and then turn on the ignition.
(You can unplug it without lowering the tank)
If you still have a "full tank" your problem would be in the wiring of the truck, if you see it as empty, then you know the short is in the tank.
If the latter, reconnect the plug, take a rubber mallet and give the tank a few good whacks. Maybe this loosens the stuck float.
Switched power goes through the sender , from the sender to the gauge, and then to ground..
The less fuel there is in the tank, the higher the resistance of the sender, therefore less power to lift the gauge needle.
An "always full tank" therefore means that you have a short circuit somewhere, I'd start by disconnecting the electrical connector on the tank and then turn on the ignition.
(You can unplug it without lowering the tank)
If you still have a "full tank" your problem would be in the wiring of the truck, if you see it as empty, then you know the short is in the tank.
If the latter, reconnect the plug, take a rubber mallet and give the tank a few good whacks. Maybe this loosens the stuck float.
The following 2 users liked this post by AlpineRAM:
Kerley (02-15-2018),
nothingbutdarts (02-15-2018)
#11
Registered User
If you haven't dropped the tank yet, I recommend you lift the bed. I have dropped Chevy truck tanks before, and it (to me) is a real pain. When I had to replace the fuel-level sender on my Dodge/Cummins a few years ago, I decided I would tilt the bed. I'm glad I did - it was much less hassle. If you have a floor jack, a section of 4x4 (I can't tell you what length you'll need), and a couple of 2x4s (maybe 2' long?), you can tilt the bed. Remove the bed attachment bolts on the drivers side and loosen the bolts on the passenger side enough to let the bed rotate high enough to the passenger side yet keep the bed from sliding. Use the floor jack and 4x4 (on end) to lift the bed, and put the 2x4s between the bed and upper inner edge of the frame rail. You want the 2x4s at right-angle to the bed and centered on the inner edge of the frame rail so they cant slide as they take the weight of the bed - you'll need a helper for this. This may sound risky to some, but it worked with no problem for me with my wife helping. Of course, choose the method you feel most comfortable with - the risk is yours.
I applaud you for still twisting wrenches at your age - I'll probably still have to be doing that myself when I hit your age (I'm mid 50s now - how did that happen).
I applaud you for still twisting wrenches at your age - I'll probably still have to be doing that myself when I hit your age (I'm mid 50s now - how did that happen).
#12
Registered User
Thread Starter
If you haven't dropped the tank yet, I recommend you lift the bed. I have dropped Chevy truck tanks before, and it (to me) is a real pain. When I had to replace the fuel-level sender on my Dodge/Cummins a few years ago, I decided I would tilt the bed. I'm glad I did - it was much less hassle. If you have a floor jack, a section of 4x4 (I can't tell you what length you'll need), and a couple of 2x4s (maybe 2' long?), you can tilt the bed. Remove the bed attachment bolts on the drivers side and loosen the bolts on the passenger side enough to let the bed rotate high enough to the passenger side yet keep the bed from sliding. Use the floor jack and 4x4 (on end) to lift the bed, and put the 2x4s between the bed and upper inner edge of the frame rail. You want the 2x4s at right-angle to the bed and centered on the inner edge of the frame rail so they cant slide as they take the weight of the bed - you'll need a helper for this. This may sound risky to some, but it worked with no problem for me with my wife helping. Of course, choose the method you feel most comfortable with - the risk is yours.
I applaud you for still twisting wrenches at your age - I'll probably still have to be doing that myself when I hit your age (I'm mid 50s now - how did that happen).
I applaud you for still twisting wrenches at your age - I'll probably still have to be doing that myself when I hit your age (I'm mid 50s now - how did that happen).
#13
Registered User
If you tilt the bed and use 2x4s to stabilize it- cut a "swallows tail", a V-shaped cut into the end that you put on the frame rail. It can't slip out like that.
Take care!
Take care!
#14
Registered User
Thread Starter
kerley
#15
Registered User
I found it a lot easier to drop the tank, 2 bolts and the sender attachments. I lowered it on a floor jack with a 3' 2x12 to stabilize....just my .02