fuel sender pi$$ing me off

[ShelbyDogg]

I get them where I get them and they all work. But I tweak everything just like putting a new quarter on; you can't expect it to fit on every car the same way.

I bought 3/8 sending units on e-bay for $50 that work.  My last one, in my resto, I just got from VANS with my tank and it works too.

  I adjust them when I install them, just like the factory probably did when they installed them.

[Jim]

Everybody seems to forget about that 10 to 12 foot "resistor" between the gauge and the sending unit.

I need to back track mine and see just how many splices there are in that 40 year old wire.

I'm going to burn some fuel off before I pull the sending unit again.

On a side note: Ever have a 1/4" spark shoot out the tip of your finger while working on a fuel system and laying on a creeper?!?! YIKES!

My creeper has a nasty tendency to build up a static charge. I get zapped every time I touch the car body. Just got done installing a ground strap on it. Going to fix that problem once and for all.

[Super Blue 72]

Everybody seems to forget about that 10 to 12 foot "resistor" between the gauge and the sending unit.

I need to back track mine and see just how many splices there are in that 40 year old wire.

I'm going to burn some fuel off before I pull the sending unit again.

On a side note: Ever have a 1/4" spark shoot out the tip of your finger while working on a fuel system and laying on a creeper?!?! YIKES!

My creeper has a nasty tendency to build up a static charge. I get zapped every time I touch the car body. Just got done installing a ground strap on it. Going to fix that problem once and for all.

   On my wiring under the rear seat mice have bitten into it... 

Scary about the spark! 

[shadango]

Oh, I know about being pissed at a sending unit...LOL.....I have a  similar thread here, with the same results....I am on sending unit 4 now (the last 2 are from Roseville and are the best results so far....)

But I plugged mine in and they read almost empty on a half tank, etc.  I tweaked the arm and after trial and error it reads fine.....full tank, half tank etc....and its accurate.   AT half tank, I fill up and it takes about 7-8 gallons....at 1/4 tank it takes 11-12 gallons.

But I STILL have dead spots at around half a tank and 1/4 tank that come and go as I drive...always at the same levels....predictable as they seem to happen in the same spots.

Now, I have not gone front-to-back on my main wire, but what I can see appears to be in great shape...thats the section that starts at the sender and goes into the trunk and into a harness.....its like new, really....the rest is in its harness and ripping apart a working harness, to me, is dumb.  I may at some point run a new wire just to test...but the way it behaves sure doesnt seem to indicate a wire issue I dont think...but who knows.

 

Someone here PMd me some info from another site where they are soldering a thin wire from the float arm to the body of the sender ......seems that the arm looses contact/ground during its swing due to a design issue where it pivots.....now THAT meakes some sense....

This is not an isolated issue...do a google for "mopar sending unit" etc and there are tons of people with these issues.

As far as the units needing tweaking.....Sure, I can understand a LITTLE discepancy....but showing almost EMPTY when its got a half tank of gas??  Thats not a tweak...thats a major issue. And all 4 have done it....leading me to wonder if I had the wrong tank or something.

[cudagirl4406pk]

Well i have a aftermarket autometer guages and a factory sending unit in the tank and it is 1/4 tank off reading all the time .What a piece of crap design.What is the part number from rosevelt parts for the unit used chryco?


michele

[burdar]

Someone here PMd me some info from another site where they are soldering a thin wire from the float arm to the body of the sender ......seems that the arm looses contact/ground during its swing due to a design issue where it pivots.....now THAT meakes some sense....

I read that post too but forgot to save it.  Do you have the link?  I got my sender from Year one more than ten years ago and its been sitting on the shelf.  I think I'm going to do that to mine just to be safe.

[ShelbyDogg]

I solder a wire to the tube right below where the rubber hose would slip on or right on the plate itself, so I don't use the clip on ground strap.  But this will not help the gauge reading your tank gallons if you don't know how to adjust it.

[shadango]

I read that post too but forgot to save it.  Do you have the link?  I got my sender from Year one more than ten years ago and its been sitting on the shelf.  I think I'm going to do that to mine just to be safe.

It was Solarguy who thought of me and sent it (Thanks again solarguy!)  and here is the link....

http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=5895846&an=0&page=0&gonew=1#UNREAD

[JayBee]

That tip sure sounds like a logical fix as long as there's the proper consistant resistance sweep when tested out of the car. Mine went from 10 to 70 ohms on the bench but intermittent operation in the car.

When I think about it, the only place that the internal pick-up arm can find a ground is between the shaft and the hole it goes through. Combine that feable connection with only using 5 volts (that's pulsed at that), possibly some oxidation on the surfaces and x feet of wire to the gauge it's a wonder that it ever reads anything. On top of that, the float is moving around in the tank, so how often is the connection at the pivot hole making and breaking. Thanks for that link, I'll be definately doing that when/if I take the sending unit out.

If anyone else gets around to trying that first can you please post how you made out.

[Jim]

Pulled the sender again today (after reading "E" and draining 5 gallons).

Bent the tube (w/ my tubing bender) a bit to get the float and the pick-up to sit a little deeper in the tank. Also bent the float arm down a smidge.

With about 5 gallons in the tank, it was reading less than 1/8. After filling it up, it almost went to full.

It appears it's getting slightly better. Might pull it one more time and bend the float down another smidge.

[JayBee]

    My fuel gauge is finally working.
 
Once I took it out the first problem was obvious, the float was full of gas. I could feel the extra weight and hear it sloshing around when shaking it. After dunking it in water, there were visible bubbles too. NOW, get this, when I checked for bubbles again (a few hours later) they stopped but you could still hear gas inside. Maybe the brass contracted enough from the cold water to seal the pinhole. I'd recommend the floats be put into boiling water first before installing in the car. Anyway, I just reused my original

Next, I checked my resistance sweep and got a nice 10 to 70 ohms with just a little hesitation around the 20 ohm area. So, I did that "solder a wire" recommendation, re-checked the resistance and got a nice consistent 9.5 - 70 ohms with NO hesitation around the 20 ohm area. It's very important that the range be nice and steady with no dead spots, otherwise some internal adjusting will be needed if the added wire mod doesn't achieve that.

Then, put it in the car, turned the key and the gauge came up to what my guess would have been ( about 1/4 after driving 160 miles on a full tank).

As for the 5v regulators, here's my experience. I bench tested my original mechanical one and, as mentioned before, my meter would peg from anywhere between 3.5 to 12 volts. The solid state one in the car sweeps from 0 to 3.5/4 volts (no 12volt pegs). I swear that it's actually going to 5volts and it just doesn't register that because my analog meter can't react fast enough to the change.

Anyway, I'm a happy camper now and only hope it doesn't leak when I fill it up. Hope this all made sense and maybe helps out anyone else.   

[ShelbyDogg]

Glad to hear thai it is fixed. I did say check the float to make sure it wasn't leaking.  If you ever need a new float. You can get one at a Ford dealer. Just bring in your old one.

[shadango]

    My fuel gauge is finally working.
 
<snip>
 So, I did that "solder a wire" recommendation, re-checked the resistance and got a nice consistent 9.5 - 70 ohms with NO hesitation around the 20 ohm area.

hey jaybee...wondering if the "solder a wire" fix worked for ya, long term?   Can no longer find thereference to it on moparts for followups. and so far you are the only one here who I can find that tried it.....

My gauge is still reading consistently goofy.....very predictable.....so thinking this fix will be the next step......

Did you use regualr solder or what? What size wire, where di you solder it etc??

[JayBee]

shadango, After replacing the leaking float AND the "wire" mod I've had no problems with the gauge. One thing that does bug me a bit is it's "reaction time". What I mean is, for example, if I'm cruising and see 3/8 of a tank - then park it - then go out later, the gauge will read 1/4 and climb up slowly to almost 3/8th. Other than that it's working like a charm. I used regular electronic solder, one of those little torches that uses a butane lighter, and I believe it was 16 gauge wire. The first pic is from the Moparts board, the other 2 are mine, hope you can make them out.

I cant stress this enough, after the wire fix you have to meter the sweep and make sure it's consistent and smooth otherwise it may be time to go inside it.

[shadango]

Sp I guess the extra wire doesnt interfere with the sweep of the arm at all?   When I did a sweep check on mine before it seemed to be OK.....not till I have it in a tank full of fuel does it act up....of course...LOL

I think this is worth a try for me too.....just have to buck up the patience to do it....had that damn unit out of my tank so many times, and had to siphon so much gas to do it....grrrrrr......