needing fuel gauge

[bbqfan5909]

Fellas,

My fuel gauge I believe is shot (needle is past the E and all connections seem to be in tact). Where would be a good place to look for a replacement gauge?

Thanks in advance,

Casey

 

[Warthog]

The tech manuals have a troubleshooting section for the fuel gauges. Usually it is a bad connection at the tank or along the frame rail. TM 9-2320-289-20 Chap 2, Paragraph 29
Fuel Gage Inacurate.

LMC, Truckandcarparts or any of the restoration companies will have a replacement diesel fuel guage. Cost is high.

You might be able to find a used one from a fellow member. Check with HAWKMAN as he has a few parts trucks.

 

[4x4 Forever]

Check the grounds around the tank before you order one. Loosen connection and then tighten...

 

[bbqfan5909]

I dropped the tank and checked connections, still no reading. Anyone have the fuel gauge part number?

Was hoping Napa would carry it?

 

[hemi348]

Here it is from TM-20,

29. FUEL GAGE INACCURATE​

Step 1. Check 20 amp ignition fuse.
Replace if burned out.​

CAUTION​

replace switch.
trace circuit. (See wiring diagram F-4 or​

DO NOT leave key
follow this caution
in “RUN” position for more than 2 minutes. Failure to
may result in damage to glow plugs.​

Step 2. Disconnect fuel tank sending unit ground from frame. Turn key to “RUN” position.
If fuel gage reads “F“ (Full), perform step 3.
If fuel gage does not read “F” (Full), replace fuel gage. (See paragraph 4-7)​

2-70
Table 2-4. Electrical Troubleshooting
TM 9-2320-289-20
(Con’t)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION​

Step 3. Disconnect pink fuel tank sending unit lead and touch lead to any ground.
If fuel gage reads “E“ (Empty), replace fuel tank sending unit,
paragraph 3-11 or 3-12)
If fuel gage does not read “E” (Empty), replace fuel gage.
paragraph 4-7)​

 

[Warthog]

I dropped the tank and checked connections, still no reading. Anyone have the fuel gauge part number?

Was hoping Napa would carry it?

From the TM 9-2320-289-20p parts manual

The LIQUID QUANITY INDICATOR - GM 6433429

NAPA doesn't have it.

Like I said before.

LMCTRUCK.COM - 36-1966 - $59.99
TRUCKANDCARPARTS.COM - 82-34477 - $65.00

or any of the restoration companies.

With these trucks being 25+ years old, the local parts houses may be able to order it, but they won't stock it on the shelf.

 

[Barrman]

The "trace circuit" notation is very important for the fuel gauge. I found a broken but held together and not conducting wire on mine.

I would suggest you pull the gauge panel and 1) verify power is getting to the proper pin on the gauge plug, 2) use a DVOM to make sure the path on the flexible pc mat is good from the plug contact to the fuel gauge lug, 3) using a 12V power source, put power to the gauge and see if it moves. Only then do you need to replace the gauge if it doesn't work.

LMC has new ones, junkyards are a great source for used and of course other members here. They show up on ebay a lot too. Just be very carefull with the pointer when cleaning one. I broke one off while trying to clean the face.

 

[89m1007]

My wife's 09 had the circuit track burnt up and I ran a replacement wire

 

[bbqfan5909]

The "trace circuit" notation is very important for the fuel gauge. I found a broken but held together and not conducting wire on mine.

I would suggest you pull the gauge panel and 1) verify power is getting to the proper pin on the gauge plug, 2) use a DVOM to make sure the path on the flexible pc mat is good from the plug contact to the fuel gauge lug, 3) using a 12V power source, put power to the gauge and see if it moves. Only then do you need to replace the gauge if it doesn't work.

LMC has new ones, junkyards are a great source for used and of course other members here. They show up on ebay a lot too. Just be very carefull with the pointer when cleaning one. I broke one off while trying to clean the face.

I got the dash pulled off this afternoon. I can only get the gauge to move if I add 12v to the pin on the fuel gauge that is supposed to be where the resistance is. Does this mean my guage is busted or good?

The harness has one wire reading 12v which is the third pin from the bottom on the right hand side. I am getting a ohm reading from the top pin on the right hand side but is not consistant because my multimeter is a piece of junk.

 

[DTL]

I just went through this same issue on my M1008 this afternoon. I cleaned grounds, chased wires and everything checked out. However, the fuel gauge would still cycle to E as soon as the key was on (with full tank of fuel). I ended up tracking it to a crummy connection between the gauge itself and the back of the panel. There are 3 "slip" connectors behind the gauge and one or more weren't making good contact. I very carefully squeezed them tightwe and reseated the gauge. Now it works. Go figure. Glad it wasn't a $$$$ sender.

 

[bbqfan5909]

I just went through this same issue on my M1008 this afternoon. I cleaned grounds, chased wires and everything checked out. However, the fuel gauge would still cycle to E as soon as the key was on (with full tank of fuel). I ended up tracking it to a crummy connection between the gauge itself and the back of the panel. There are 3 "slip" connectors behind the gauge and one or more weren't making good contact. I very carefully squeezed them tightwe and reseated the gauge. Now it works. Go figure. Glad it wasn't a $$$$ sender.

Sounds like your gauge moved before you cleaned the connections?

Currently my fuel gauge sits on empty and will not move unless i use a 12v jumper wire where the sender wire hooks up. Now it is stuck on "F" full, Is the needle supposed to return to "E" empty when current is no longer applied?

It will not move however when voltage is applied to the other side where the gauge actually receives its current from the wiring harness.

I tested all of the circuit and I can get current to every connection so I know that is not the problem. All signs seem to point towards the gauge but I hate to buy the wrong part.

Is the gauge supposed to move when you apply current to the gauge without and resistance (ohms) from the sender?

 

[DTL]

I don't know what it will do if you just put power to it. Mine would move from E back to about 1/3 when power was shut off. As soon as power was back on, it went straight to E. Basically it was stereotypical "bad sender" behavior. Fortunately I was able to stumble across the actual culprit before spending money and hassle on the sender.

 

[Barrman]

The -20 and my personal experience is this.

Needle at F or past with power on means sender or sender wiring bad or sender ground bad.

Needle at E or not moving means no power to it or bad gauge.

If you have cleaned everything and it still doesn't move with power to the proper power lug, then go find a junk yard gauge for $5. The gauge is just an Ohm meter. No ground/open circuit makes it read past F. Grounded or 0 resistance gets you E on the gauge. While you have the panel out. Putting power to the gauge should get it past F. Keeping power on and grounding the sender lead should have it go back to E in a real slow movement. Pulling the ground with the power still on will have it floating back to F.

 

[bbqfan5909]

Thank you all very much for the help. Slowly I am shooting the trouble. Turns out the gauge does work and after a bunch of cuss words and broken fragile pieces I got the gauge to move to "F" while connected to the harness. Turns out the culprit to the dead gauge was dirty connections. Unfortunately however the needle keeps going even though the tank is quiet empty.

But there is hope because grounding the resistance lug did move the needle back down to "E". So we will see if grounding the sending wire to the frame will produce the same results.

 

[bbqfan5909]

I guess there is two different sized tanks (25 & 30 gallon) for the new sending unit...how do I determine this on my 86 M1009 ?

Thanks in advance

 

[Zero_cool]

Recently my gage would randomly go to E then back to correct level.
I dropped the tank to clean out the junk inside and replace fuel lines.
Now when the key is off it slowly goes to 1/4 tank but when i turn the key on it drops to E.
The TMs suggest that its a bad gage , but I want to test it before I purchase one.
I tried to read the TMs electrical diagram but to me it looks like a bunch of noodles.

Questions #1 So where does the power come from? I pulled my gage off and there are 3 pegs but no wires to any.

#2 Which peg do i put 12v to and witch one do I ground?

#3 When you say clean everything are you talking about cleaning the pegs?

 

[mr.travo]

I am having problems with mine too. She used to work just fine. Earlier this year, when I rebuilt my dash cluster, I cleaned all the contacts (in the entire dash) and everything worked fine. Now that I am driving her everyday and sometimes on long trips (3 hours) it is all over the map. I don't think my gauge would be bad, nor dirty contacts. I am going to crawl under there and see if I can find some jack up wires or something.

Zero cool- I would clean the contacts behind the gauge (the pegs and the holes in the cluster) to ensure they are making good contact. If that doesn't do anything, I would guess that it's a wire not making good contact (probably like mine).

 

[CycleJay]

Howdy,

I am having the same trouble with my gauge.
So I read the tm's and ran the tests for it, to determine what is wrong.
And from that, the answer is that my gauge is bad. So I need a new one.

So I will either order one from LMC truck, or take it to a local shop that is
capable of repairing it.

Good luck to all of you with the same problems.

Good night,

CJ

 

[berrett]

My fuel gage is also stuck on Empty.
I pulled the ground from sending unit to frame , gage still at Empty.
TMs say gage is shot. I followed step 3 anyways and removed the pink wire off the sending unit , gage goes to Full , grounded pink wire and gage goes back to Empty.
Tms now say sending unit is shot.
Im thinking that just pulling the ground to frame , the tank is still being grounded threw the straps? Since the tank is full i just removed the box.
I tested for power on the slip clip and have 14.45 v , when i jump that to the gage it does not move but when i keep the 14.45 v on and ground the bottom peg the gage goes to full.
What the heck do you guys think is going on?
Bad gage ?
Bad sending unit?
Thanks

and whats a gimpyrobb?

 

[tankie88]

My gauge went haywire one day.It was showing less than was in the tank.Found the cause in 5 mins.It was a bad ground where the ground wire comes off the tank sender unit.The screw/bolt on the chassis rail was rotted through.New bolt/screw,new hole,new connector job done.