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Fuel guage reads zero


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A few years back, I replaced the fuel pump. Ever since, the fuel gauge has not worked. Started out getting partial readings, but now reads zero or one bar. I have finally tired of this condition and want to take care of the problem. Any ideas where to start looking. Hate to have to drop the tank again. But help is needed. Thanks in advance for any tips.

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Here's a recent thread on the sender. Apparently not available new anymore. Do need to drop tank unfortunately. :mad:

No link.

The problem is in the sending unit/gauge unit. It could be the wiper on the wire wound resistor attached to the sending unit right above the fuel pump is not making good contact but also there are some small contacts on the rotating arm that break off.

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I agree that the problem is probably in the tank. However before pulling the tank there is a test you can do.

Back at the tank there is a three wire connector, you need a DVM to check for 12v.

See section 8A-82-13 (1990 service manual)

With ignition in RUN position. Check the following.

(1) Pink/Black wire to ground...... should have 12V

(2) Pink/black wire to Black/white wire .... should have 12V

(3) Pink/black wire to purple wire............should have 12 v

According to the manual, if 1 or 2 are open, it is the sending unit.

If 3 is bad, it is the BCM

In the attached photos, the tan housing is the resistance wrap, if any of those wires are broken the gage will not work. This tan part seems to be common on several GM cars and you can find a good one and install on your sending unit.

The other picture is the wiper that rubs against the resistance wrap. The little finger can be broken/damaged or the back size rubs agains a conductor and the little tabs can be broken on that. Again you can make one work from another GM car of the same vintage. Riviera, Toranodo, Seville, and Eldorado all have the same parts but the entire unit will not usually transfer to the Reatta. Other GM cars may have parts that will work but my knowledge does not go that deep.

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The contacts I was referring to that are common to break are in Barney's second picture. Right above the pink wire in the center you will see a round piece of plastic that holds that end of the axle of the rotating part. In his picture right above that is a sort of horseshoe looking piece of metal. This piece has two metal contacts on it and these are the contacts, because they are thin an small will corrode and break off.

Everything is riveted together so a little hard to rebuild. Oops, sorry, I used the wrong term, I meant to say repair.

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I agree with Jim....... pictured below is my solution.

I take the finest (smallest) wire that I have and wrap it around something that is about 1/2 inch in diameter (a sharpie pen works) make about 3 wraps.

Solder one end to the wiper and the other end to the brass that the broken contacts touched.

The fine wire with wraps allows the arm to swing freely but give the contact you need.

post-30596-143138840687_thumb.jpg

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I agree with Jim....... pictured below is my solution.

I take the finest (smallest) wire that I have and wrap it around something that is about 1/2 inch in diameter (a sharpie pen works) make about 3 wraps.

Solder one end to the wiper and the other end to the brass that the broken contacts touched.

The fine wire with wraps allows the arm to swing freely but give the contact you need.

GREAT IDEA

I have turned downed sales of sending units because that wiper was broken. I will try your fix next time on one of the sending units I have on the shelf.

That is actually the same way the clock spring works on the Reattas with an airbag. There are many wraps of ribbon cable inside the clock spring housing. They are wrapped loosely and when you turn the steering wheel they tighten and loosen as needed maintaining an always positive contact.

Edited by Jim (see edit history)
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GOOD LUCK!

I got the last new one that was in the country, in and seems to work great!

Jim,

Glad to see you are still involved. Hopefully you will be able to make it to the Charlotte meet. That is not too far from your home.

I thought about you during the Super Bowl and felt bad for you that the Patriots didn't win but if I could have had it my way both teams would have lost. Not a big fan of either but I guess I was glad the Giants won because the beat the Packers on their way.

I remember when you got that last sending unit and being new, you should have no problems in the future. Unfortunately the contacts inside are small and can corrode and break.

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Barney, That will be a good test for me to add to my website. May I use your photos?
Ronnie......... no problem,
I've added information about testing the sending unit and repairing the wiper to my website. Let me know if mistakes need to be corrected. I think I understood what you described for the wiper contact repair. Let me know if I got it wrong and I will remove it.

Fuel Gauge Sender Troubleshooting*-*ReattaOwner.com

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My resistance card on my sender was rusted beyond repair. Searched web and found a few companies that will rebuild the sender. I will look through my records for the company that I bought from. He sold me just the resistance card for around $30 shipped.

It appears that the sender assy is the same for all Reattas, but the resisitance card for the '88 &'89's are specific. (CRT equipped cars I'm guessing). Also, judging from salvage yard cross-referencing, the Riv, Eldo & Toro senders for the lat '80s through early '90s are the same as the Reatta, just different resistance cards. car-part.com is a great source to use to cross-referencing.

Hope this helps.

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I don't think there is any difference in the resistance winding. The difference in the 88-89 is outside the tank. Below is a photo showing the differences outside the tank. Note one has plastic flexible lines and the other has steel lines. This was done for various reasons, but inside the tank they are all quite similar.

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  • 1 month later...

Attached are a couple of better photos......... both of these parts are from a late Buick Roadmaster wagon, so the parts were used in several years of GM product.

One is the resistance wiring, these are a common part, note the wavy-ness of this part, things like this keep the gage from being linear.

The other part is the contact, this is a good one. Note the two small contacts on each side of the post. Jim noted these are often brittle and fall off just looking at them.

post-30596-143138917493_thumb.jpg

post-30596-143138917511_thumb.jpg

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  • 1 year later...

Barney, thank you for your great descriptions and photos. I was able to repair my sender with no additional parts, just a lot of time adjusting the contacts and reassembling.

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