Best fuel sending unit please

[JayBee]

  I feel your pain shadango 

[shadango]

I just dont understand why quality is so poor on these.

I dont buy the "gauges werent accurate 40 years ago" concept at all......Certainly, it wouldnt have been acceptable back then for a tank to read half full when it was full.  Or for it to read all whacky all the time.

The Roseville unit *does* appear to be of better quality overall......but at $110, it should read properly right out of the box.  heck, at $70 the "cheap" ones should too!

All I can hope is that this one just needs the arm bent some...... ...and even then its a guessing game.  And then once it reads "full" when full, I have to run a whole tank of gas through just to see if it gets whacky at all.

No, thats not quality, to me.  I have replaced a few sending units in my time.....admitedly on "newer" vehicles.....92 was the oldest vehicle......same job, very different results......

I can say one thing...I am getting to be an expert at doing the job....

Wish I could pull the unit without draining the tank though.........thats the biggest pain in the whole job.....and dangerous.

I guess I redo it AGAIN tomorrow.....

[JayBee]

I don't understand this either.

When my unit was bought the resistance sweep was a smooth, consistant 10 - 70 ohms all the time, no dead spots, no variations. Same thing when doubled checked before installation. Maybe the guy I paid to put it in messed it up. Of course, he won't take any responsibility because I supplied the unit. Maybe the fuel is interacting with the contactor and resistance coil to throw off the readings. I'm really hoping it sorts itselfs out after a few more tank fulls.

[shadango]

I am at wits end.

Spent the last 3 hours screwing with this.

No matter how I bend the float arm I cant get it to read high enough to register a full tank.

I had a pretty much full tank when I pulled it into the garage.  About 30 miles on it.  I have been getting 10-12 mpg, so that means that out of the 16.5 gallons (according to the service manual) the tank should hold, the gauge should read a little over 3/4.  It was reading 1/2 tank.

Ok, so I figured, bend the float arm down a bit.

So I drained about 5 gallons of gas from the tank..so tank should now read about half a tank.....

No matter how I bend the arm I cant get it to go above 1/4 tank.

Running a ground direct to battery.

The sweep still looks smooth on the bench.

Hooked up the unit out of the tank and got a reference as to where half should read and am using that to bend the arm up or down.

Nothing.

I just dont get it.

At least the cheap unit got me to full.   

So I think this Roseville one has to go back.

This truly sucks.  So much for "just install it and be done".  i knew it couldnt be that easy for me. 

On top of that, while I was under there I found that the left axle seal is leaking again.   

I cant win today.

[tommyg29]

I thought the tanks were 18 gallons, less maybe a gallon or two unusable. There could be some difference in your tank, especially if its not oem. Maybe the float was hitting the top of the tank at 3/4 full so it wouldnt register as full, but I would think bending the arm down would have solved that.

[shadango]

Well, my service manual for 1972 says 16.5 gallons total capacity.

If the tank held more than 16 gallons, then it should be reading more than half as I only took 5 gallons out of it plus the gas used in the 27 miles since I filled up.  So either way it would be wrong.

No matter how much I bent the arm up or down in the factory-bent spot I couldn't get it to read half a tank which it should be reading.  At some point, in fact, bending the rod down more just makes the reading go the opposite way because the float swings in an arc.....

Now that was bending at the "factory" bend.

Checking the gauge with the sender hooked up outside the tank before I bent it, I found that when the float was maxed out to the "top" stop, the gauge barely read full.  So it was off a bit  anyways on that end.  The sweep was still smooth.....

I just tried bending the rod closer to the pivot....that effectively changes the ohms reading at a given location, but it also changes the max and minimum readings. 

I bent it several times till I read half a tank when installed in the tank.

Got it to that point now. Added the 5 gallons of gas back in and now I am reading way over full.  It should read slighly less I would think

It would be better I guess to fill the tank full and then tweak the sender till it reads just perfect on full...but that aint doable realistically.

So I will try it like this I guess for now....At least I know that when I have a half tank I should have a half tank...or 8-9 gallons......LOL

I wonder how much time Roseville gives for returns?   

At this point I will have to fill up again and burn down the tank of gas, using my previous mileage readings (10-12.5 mpg) to see where I stand.  My guess is that it will still read some-what wrong...may drop fast or something.....but hopefully at half and below it will read accurately.  Thats where you really need accuracy if you have to pick a region I guess.

My last gas mileage reading was 12.5 mpg....went 27 miles since  the last fillup....so yeah it should read pretty full I guess....but way over full, I don't know.

FYI, the ohms read at about 4.5 when "full" using the stop......the "empty reading is less than the 75 ohms originally...this may mean that I will be showing some gas in the tank when its actually empty now that I sit and think about it......so most likely will have to weak some more...

I guess we will see...this is so frustrating.   

[BIGSHCLUNK]

Wow, I can't belive how long this thread has gone on, but I do know why!!  As stated earlier I had mine in and out a bunch of times. Back and forth tweaking the arm and what not. And I still dont get a perfect reading either. A full tank always reads a hair below the "full" line. And seems to drop quicker than it should, if thats possible with a HEMI??? A bunch of times I've stopped for gas thinking I was about out only to take on 9-10 gallons.

I guess my biggest peeve is that my old sender worked PERFECT!!!!!!  But I switched from 5/16 to 3/8 to feed the HEMI, and have the return line. BUT to be honest have never noticed a difference!!   

I guess you just can't get a good chinese made sender, no matter who you buy it from....

[BruteForce]

I guess you just can't get a good chinese made sender, no matter who you buy it from....

Part of the preflight checklist for light planes is to unscrew the gas cap and poke a stick in there to see if you really do have gas in it, regardless of what the gauge says. Too bad there's no practical way of doing that with a mopar tank.

[alphabuck]

i bought a new sender off ebay.  think i paid like 50 bucks for the thing and got exactly what a paid for.  a piece of steaming dog dung.  i was lucky enough to have the tank out and empty (thanks again chris) and i noticed when i installed the sender the pickup and float only went about halfway down into the tank.  i didnt look but i bet the float would have hit the top of the tank before it could have registered full.  i would have had to put close to a half a tank of gas in there before the filter or float even got wet let alone register or draw any fuel. 

i ended up customizing my unit.  i cut the sucker off up on the top and cut it off down on the bottom.  a couple of compression fittings and a length of 3/8ths steel line later i had the pickup and float about 1 inch off the bottom.  i dont know if thats totally right but its got to be better than it was.

[shadango]

how did you see that the float was only going where it was going? I guess thru the filler neck hole?

[BIGSHCLUNK]

  i didnt look but i bet the float would have hit the top of the tank before it could have registered full. 

Joe, thats an idea I didnt think of...  I wonder if mines hitting the top so it never reads all the way.    I gotta admit tho.... I'm done with crewing with it for the time being.

Glad to hear you finally got the tank in tho. 

[alphabuck]

how did you see that the float was only going where it was going? I guess thru the filler neck hole?

right i looked down in through the filler neck hole with a flashlight.  the filter sock was a good 4 inches off the bottom when the sender was fresh out of the box.

[MEK-Dangerfield]

right i looked down in through the filler neck hole with a flashlight.  the filter sock was a good 4 inches off the bottom when the sender was fresh out of the box.

Did you have the sending unit turned as far to the right as you could get it before you tightened the ring? I could feel mine bottoming out. Mine still reads one line too low when the tank is full, but that seems better than what some of you are dealing with.

[pink panther]

I'm sorry you are having so many problems with this sending unit, I just don't understand it, I put mine in with half tank of gas, it read half tank, filled it up and it read full needle all the way to full on the gauge, I never bent the arm or anything, just made sure I put it back at the same exact orientation the other one was at when I took it out.

[MEK-Dangerfield]

I'm sorry you are having so many problems with this sending unit, I just don't understand it, I put mine in with half tank of gas, it read half tank, filled it up and it read full needle all the way to full on the gauge, I never bent the arm or anything, just made sure I put it back at the same exact orientation the other one was at when I took it out.

So you want to trade any of us?