Fuel Gauge not working (shocker, I know...)

[EW1BH27]

When it’s out I can’t stress enough to do the wire modification, you won’t be sorry. Just make sure it doesn’t interfere with the movement. My two videos show its value.

 

[Steve340]

I had a look at your video - good info.

 

[ColoradoCuda]

Yes EW1BH27, your wire mod looks like it makes great sense. I'm planning on implementing it!

 

[EW1BH27]

I learned about that on Moparts, that’s where the picture came from too.

 

[ColoradoCuda]

Just got my new ground strap and lock ring removal tool. Siphoned about 9 gallons out of the tank, should be well below the sending unit. I did another resistance test, the previous one showed 57 ohms with what I thought was a full tank, after removing about 9 gallons, it reads 76.3 ohms. Going to pull the old unit out and study it before I order a new one, but I expect a new one is the way to go regardless.

 

[ColoradoCuda]

Well folks, my frustration with this project is really growing. I was excited to use my new lock ring removal tool, but it will not get good enough purchase on the lock ring to remove it. It just doesn't fit that well. I've tried modifying it to work, but still no good. It also appears that my sending unit was probably painted while installed when the tank was cleaned and painted. Arrrggh!

At this point, I'm considering taking the whole tank out and either see if I can remove the sending unit, or just replace the whole tank too. It looks like I may have to remove the rear valence panel (where the exhaust cutout holes are) to get at the fasteners at the back of the tank to remove the straps. Is this correct? Does the bumper need to come off as well? It seems like it may be able to stay on if the valence is removed. It is nicely aligned, and I'd rather not disturb it. It looks like the tank removal is not a straight forward as on other cars I've worked on. Any advice please!

 

[Challenger RTA]

Bumper can stay. Was there a tank sealer put in the tank before?

 

[ColoradoCuda]

I believe the seller told me that the tank was internally coated, but I don't know with what.

 

[Xcudame]

It will most certainly be much easier to remove the fuel tank after the rear valance is removed. Those rings are tough to get off and it's possible yours may have gotten "sealed" on!

 

[heminut]

I have always used a flat tip screwdriver and hammer to remove those lock rings. In 50+ years of working on cars I have never owned a lock ring removal tool! You might have to alternate back and forth on the tabs on the lock ring to keep it from binding on you, but that method has never failed me.

 

[EW1BH27]

Same here as heminut and I’ve had mine off more times than I care to remember.

If you do get another sending unit re-use the original lock ring and gasket or buy the pair from DMT. The ones that come with all the new ones are a pain to seal if they even do.

 

[ColoradoCuda]

I love this forum! So helpful. You two inspired me, so I took a screwdriver and hammer to it and it came right off. Here is a picture of the crusty old thing, and another with it hanging upside down and the float does not ever fall by gravity of its own weight. I'm ordering a new one. I don't know what the prev owner coated the inside of the tank with, besides corrosion.

I took this opportunity to siphon another 5.5 or so gallons out, so probably have removed about 14 or so, I think it is fairly empty. I put the old unit back in just to seal the tank so I don't fill my garage with gas fumes. I'm ordering a new unit, now have to decide if I want to mess with the tank or not. Leaning toward not, even tho I'm sure it has crap in it.

 

[nigeltufnel]

GOOD GRIEF!! I've had hemorrhoid's that looked better than that!

 

[heminut]

That is one nasty looking sending unit! That gas tank has definitely had water in it at one time or another! You might try sticking your cellphone up to the sending unit hole and see if you can get some pictures of the inside of the gas tank. If the inside of the tank looks anything like that sending unit I would seriously consider getting a new tank.

 

[Xcudame]

I agree, a new tank may be necessary as well!

 

[ColoradoCuda]

I will remove the unit and see if I can get a photo of the inside of the tank. I agree, a new one may be in order!

 

[Katfish]

I'd pop the cover off the rheostate and see what it looks like.
Granted the arm looks bad, but none of that matters, the only part to be concerned with is that spring and feeler that rides on it. You just might be able to clean that up.

 

[EW1BH27]

What Katfish said. a good soaking in Evaporust might bring it back. If it were me I'd try and resurrect it, but I like doing that kind of stuff. Here's what a nice inside looks like.

 

[ColoradoCuda]

Well, today I cleaned up the old sending unit a bit (not a lot), and got the float arm swinging freely. Oh, the float is about 1/4 full of gas. With the unit outside the tank, I hooked it up with jumpers to the gauge wire and a ground, set the float to the high position, and sure enough, my gauge read full. Mystery solved (mostly). I was considering just putting my new sending unit in when I get it and call it good.

Then I put a flashlight and my camera up to the hole and looked at the inside of the tank. It is hard to get a good view, but the sides and upper ridges on the bottom looked pretty good. But there appears to be gunk in the bottom of the lower ridges. There is also some sort of box looking thing hanging from the top, sort of in the middle of the tank. Maybe a baffle of some sort? This seemed to have black crud on the face of it that I could see.

If you recall from earlier in this thread, I mentioned that I had run out of gas, but was only able to put about 10 gallons in. So I'm thinking that maybe the sediment crud in the bottom of the tank clogged up the filter on the pick-up tube. When I put more gas in, it may have temporarily dislodged it and I was good again.

So I've decided to bite the bullet and get a new tank.

 

[Steve340]

Sounds like a good plan.