67 sending unit

[Richard A.]

My fuel gauge read about 3/4s full when the gas tank was full during the summer drive time. It registered fine at empty with the dial to the left where it should be. This winter I pulled the sender and attached the wires to it and slowly moved the float on the bench and it read the same: good at the empty end but only going to 3/4s full when completely opened (float all the way open). Is there any way to fix this? The sender is an AC original and I hate to replace it with a cheap one and new ones are spendy. Thanks for any advise I can get in advance. Rick

[John H.]

Re: 67 sending unit

My fuel gauge read about 3/4s full when the gas tank was full during the summer drive time. It registered fine at empty with the dial to the left where it should be. This winter I pulled the sender and attached the wires to it and slowly moved the float on the bench and it read the same: good at the empty end but only going to 3/4s full when completely opened (float all the way open). Is there any way to fix this? The sender is an AC original and I hate to replace it with a cheap one and new ones are spendy. Thanks for any advise I can get in advance. Rick

Rick -

You might talk to John Wolf (www.antiqueinstrument.com) - he rebuilds/restores original AC sending units.

[Chris E.]

Re: 67 sending unit

I had Wolf do my original 67 fuel sending unit. Works great!! Highly recommended.IMG_1208.jpgIMG_1209.jpgIMG_1210.jpg

[Richard A.]

Re: 67 sending unit

Thanks, Chris and John. Rick

[Larry M.]

Re: 67 sending unit

Rick:

You really need to get a VOM (volt/ohm meter or multimeter) and then retest the sender. It can be done on the car with the car wires disconnected. Get the tank near empty. Then use a person with a small hand or a coathanger and and run the float up and down. I believe that the readings are EMPTY = 0 ohms and FULL = 90 ohms. You can also check approx at mid-way of travel for 45 ohm. This will tell you if the sending unit is good or bad. You may be able to also SLIGHTLY bend the float arm to adjust, but I would do this with the sender removed from the car......but others have done it installed.

It could be that the gage in the dash is bad or needs adjustment, not the gas tank sending unit.

Larry

[Ronald L.]

Re: 67 sending unit

Generally its the gauge (with these symptoms) but you should search this site for John's article on diagnosing these, it could be a grounding issue too.

[John H.]

Re: 67 sending unit

Generally its the gauge (with these symptoms) but you should search this site for John's article on diagnosing these, it could be a grounding issue too.

Here's a link to the article for diagnosing the midyear fuel gauge system:

http://www.lbfun.com/warehouse/tech_info/gauges%20&%20instruments/MidyearFuelGauge.pdf

[Richard A.]

Re: 67 sending unit

Thank you all for your responses. I did the Ohms check of the sender on my work bench and found that it read properly or 0 ohms at empty, 45 ohms at 1/2 full, and about 95 ohms at full. I think my problem may be in the gauge that I installed this summer. Thanks again for your time and expertise. Rick

[Joe R.]

Re: 67 sending unit

Richard,

Here's something you might want to check. As the sending units are getting old some of the floats take on more weight thru water or gas soaking into the material and don't float as high in the tanks as they once did. This will cause a 3/4 reading. Also, some of the old ones (originals) were actually a float made of brass. Pin holes in those can cause problems.

Nearly every time the sending unit is the cause of a problem so check out the sending unit very carefully.

JR

[Larry M.]

Re: 67 sending unit

Richard,

Here's something you might want to check. As the sending units are getting old some of the floats take on more weight thru water or gas soaking into the material and don't float as high in the tanks as they once did. This will cause a 3/4 reading. Also, some of the old ones (originals) were actually a float made of brass. Pin holes in those can cause problems.

Nearly every time the sending unit is the cause of a problem so check out the sending unit very carefully.

JR

JR makes an excellent point. You can use a flashlight to see if the float is riding on the gas level or is sinking or is somewhat submerged. Another check is to fill the tank with 20 gallons of fuel and then check the ohm reading of the sender on the car. If it is 90 ohms, you are good. If it's about 65-70 ohms the float lever is bent or the float is taking on gas.

Larry

[Richard A.]

Re: 67 sending unit

I have the sending unit on my bench right now. Is there any way to check the float out of the car? I have looked online for just the float and cannot find any replacements. But I would rather keep the one I have since it is original. Thanks, Rick.