Fuel sending unit

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player1up

player1up

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So my fuel gauge stopped working yesterday, ( temp gauge works fine ) so I checked the sending unit and got 103.5 Ohms with the positive lead at the terminal and the negative lead at the body of the "sending unit". Ive read that the unit should read between 70-0 ohms so I know it's bad or my testing procedure is bad.

Did I test it correctly?
Is the sending unit something I can take apart and clean or something like that or is it just a replacement type thing?
 
You need to ground the wire to the sending unit with the key on to see if the fuel gauge pegs full. If so the sending unit may be bad or it has a bad ground. But then again, if it reads a resistance of about 100 ohms it may be ok. If the gauge does not peg I would suspect either a bad gauge regulator or the gauge itself is bad. You did mention however that the temp. gauge is ok so that may tell me the regulator is ok.... hmmm.
 
When checking with an ohm meter... first you need to zero the meter if its self adjusting or note the resistance in its leads. Either lead is conneted to the sender wire connection and other lead should go to any ground other than the sender body. This insures you are checking the chassis ground connection as well. Empty is 73.0 ohms. Full is 9.6 ohms
There isn't much user servicable about the sender. Just replace it if its faulty.
 
Ok the gauge currently reads empty, but I know it has 9 gallons of fuel as of yesterday on the way home, and I only live 5 miles from work, so...

I'll go ground the wire... stay tuned...

So, I grounded the sender wire to a shock bolt and the gauge pegged to full, so it looks like a replacement sending unit is in order.
 
So, Where would be a good place to get a replacement sending unit? I've seen a couple out on the net but anyone have a recommendation?
 
I got mine at ebay 60 bucks.
Good quality , brass float and all.
Reuse your original lock ring !
 
I got mine from Quanta great service I forget how much it was but it wasnt bad. One piece of advice, get the fuel sender lock ring wrench it will be a good investment. And another small tidbit, don't ever ground your fuel gauge straight to ground you will burn it up quickly. the best way is to hook a test light up to the gauge and then go to ground, your light will be dim and the gauge will deflect 1/2 to 3/4 way on the needle. Just a tip from someone who smoked one. Some of the old field manuals (50's) tell you how to make one, but the test light I have found is a good source for a load.
 
I ordered it from Rocket Resto ebay store. I hasn't showed up yet but when it does I'll comment on quality etc. It does have a brass float and comes with the lock ring and gasket, sock and the price was right...$61 after shipping.

Rick, That's good to know about the sending unit. I didn't ground it for long but we'll see if it's cooked when I get the new sender
 
Well I got my new sending unit and it works like a charm. 10 minute install with the car sitting nose up the driveway. The new unit looks nice, fit perfect, but without a lock ring tool I decided to use the old lock ring because the new ring has locking points on it that would make it almost impossible to remove without damaging it ( IMHO ) using the screw driver method.

If anyone has read any of my past posts, I'm a "gotta know why" type of person. So I took the old sending unit apart to see why it failed....
The general condition of the old unit should have been an indication of what was inside but I still carefully took it apart, and here are the pics.....
More than a little rusty
1 (Small).jpg
The arm has come off of the float stem
2 (Small).jpg
Huge amount of crud inside the body
3 (Small).jpg
But I'll bet that I can fix it. Why... because I like a good challenge, and a good project. :lol:

Oh, and in case anyone is wondering, I'm budgeting for a new tank. ](*,)

1 (Small).jpg


2 (Small).jpg


3 (Small).jpg
 
Congrats for having the worst pull off I've ever seen. LOL
 
screw driver is ok if your turning the ring but dont use it with a hammer to brake loose the ring it might spark,, use a brass punch.
 
The funny thing is that it was working at all... It had started not reading totally full for a couple of weeks then completely quit, but my guess is that all of the crud built up and when I filled the tank, the arm popped off.

The hardest decision of all was whether or not to put a BRAND NEW sending unit into a tank like that...


Good point about the spark thing, but I just used my hand on the back of the screwdriver, I'm not so keen on slipping and punching a hole into the tank either, let alone get blown up !
 
OMG, I'd say you found your problem... that's got to be the worst one I have ever seen. I'd drop the tank and give it a good flush too. You don't want any of that rust ending up in your fuel pump or worse.
 
Oh, I've cleaned tanks before...motorcycle tanks...a task that inhales vigorously and takes forever to get them looking nice on the inside...I can think of nothing more I'd like to do than shake a 16g tank for 2 hrs...

Maybe this :lol:
[ame="http://www.youtube.com/watch?v=U7RM6vpmdI0"]YouTube- how to clean a gas tank[/ame]

:lol: :lol: :lol:
 
Last machine shop I worked for had a vibrating tumbler machine with ceramic media. A fellow worker brought his bike tank in one day. threw 2 fists full of media inside it and c-clamped it to the outside of the machines' bowl. At the end of the day the inside of the tank looked new and the finish on the outside was unharmed.
Seems eveyone has a good idea once in a while. :)
 
Dang and I thought my old one was bad. My old one looks pretty good compared to yours. I bought my new one off ebay also.

SDC11446.jpg
 
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