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Fuel gauge issues...

S

Steve93mustanglx

Diesel fanatic!
Messages
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Location
Midlothian, VA
Hello all, this is my first post here so forgive me if I am missing a few site protocols.

My fuel gauge used to flick all around especially after it was down to half tank. It would jump erratically, and the full level went to 3/4, then 1/4, and eventually the stupid thing was point to the oil pressure gauge! Curious, I took the leads off the battery and then replaced after ~30 min. No change. So, I dropped the monster 42 gal fuel tank. The lines of the unit were wet with diesel and rusted to absolute hell, and once out I noticed slop in the float arm. I replaced my in-tank sending unit.

Guess what? No change. Que pasa?

Vehicle is 95 Suburban, 6.5TD, relocated PMD, Pinnacle exhaust, 97 air filter mod, CS-144 alt upgrade. 330,000 miles!

Thanks,

Steve
 
Steve93mustanglx said:
Hello all, this is my first post here so forgive me if I am missing a few site protocols.

My fuel gauge used to flick all around especially after it was down to half tank. It would jump erratically, and the full level went to 3/4, then 1/4, and eventually the stupid thing was point to the oil pressure gauge! Curious, I took the leads off the battery and then replaced after ~30 min. No change. So, I dropped the monster 42 gal fuel tank. The lines of the unit were wet with diesel and rusted to absolute hell, and once out I noticed slop in the float arm. I replaced my in-tank sending unit.

Guess what? No change. Que pasa?

Vehicle is 95 Suburban, 6.5TD, relocated PMD, Pinnacle exhaust, 97 air filter mod, CS-144 alt upgrade. 330,000 miles!

Thanks,

Steve
Click to expand...


Mine also spins around in circles on key off and key on. Very sparatic from full to 1/4, then slows down.

2 weeks Ago I changed out my front tank and my FSU.

GUess what, no change either.

Still sparatic, and the exact same as before. I think I have 2 FSU's that someone communicate to give me fuel level, as I have 2 fuel tanks that are automatic. Not switched.

BTW, how was your sock on the old FSU?
 
I was amazed- sock in tact, in place, and tank was spotless. For 330,000 miles I was impressed.

I only have one tank so I dont think the two are related (I still have same prob you do). I reset my PCM tonight and still same issue. GRRRRRRRRRRR
 
Very common problem. Did you check the new FSU before you installed it? I always check it with an ohm meter first then plug it into the harness and have someone watch the guage as I move the float.
 
Yup! I checked the FSU before install. It did the exact same thing- low readings- but since the old metal return line snapped off the old one when I took it out, it had to go in anyway.

Grounds... you know, I need to check. I did clean my batt terminals last week with baking soda and a wire brush, but haven't checked any engine grounds lately.
 
Should be a ground a the frame rail right by the tank.. if its the same as my gasser
 
99% sure its your sender. Check for continuity between the wiper and coiled wire, then from the wiper to the conector plug. I bet the problem it there.
Same exact problem has happend on several of mine and it was allways the FSU. You might be able to clean the wiper and or wiper pivot? New ones are $80.
 
Burning oil- I do have a new sender installed. However, no change. It did the same thing with both the old and new sender...

Deere- i did have that ground off when I removed the tank- it goes from the filler neck to the frame. No change- same issue.
 
Turbine Doc said:
Should be another gnd Steve, that one at filler neck is for anti static protection, one on my 98 burb is just above the axle tucked up high on the body, a little hard to see
Click to expand...

That is the one I was thinking of, Had problems with my gauge not working all the time on my gasser because of that..
 
Hey Rodd- yup, baffle in place. All rivets/washers present and accounted for!

Tim- that I did see but I did not pay attention to the ground under the connector. Cool- that ain't too bad to reach. Thanks much!
 
Tim, I got my prodigious girth under the Sub today and cleaned the sending unit's electrical ground. Viola! Seems to have fixed the problem. Thanks a bunch!

Next project- rewire LP to different hot source!
 
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