#1  
Old 10-16-2019, 09:47 AM
ELKHORNAOG7 ELKHORNAOG7 is offline
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Question 68FB Fuel gauge for dash rebuild

Anyone know a company or someone on PY that can rebuild a fuel gauge for a 68fb after checking my sending unit and it test good I'm most sure it must be the gauge that is giving me the wrong reading ( 3 o'clock ) with key on this just started the other week and they want ( 209.00 ) + shipping for a new one. Thank you in adv.---BOB

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Old 10-16-2019, 12:04 PM
max 93 max 93 is offline
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I used Redline gauge and clock repair in Tennessee to fix my amp meter.

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Old 10-16-2019, 12:33 PM
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Did you test the wire or just the sending unit?

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Old 10-17-2019, 10:34 AM
ELKHORNAOG7 ELKHORNAOG7 is offline
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I pulled the unit out of the tank and checked the unit by hand and at full the unit reads 92 ohms , with unit out of the tank and hooked up to gauge and I lift the float maybe (2inches) from empty the gauge reads full and if I keep lifting the float and the gauge keeps going up to (3 o clock) -----BOB

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Old 10-17-2019, 11:22 AM
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I have a gauge you can have if you cover shipping

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Old 10-17-2019, 11:57 AM
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Does grounding out the tan wire in the trunk make the fuel guage go to empty?

What kind of ohm readings did you get from the sending unit between empty and full?

Did working the sending unit by hand make the fuel guage go to empty?

Checking for empty will tell us condition of the sending unit wire from the guage back to the tank.

Clay

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Old 10-18-2019, 07:17 PM
ELKHORNAOG7 ELKHORNAOG7 is offline
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Clay: When I checked the sending unit out of the tank at empty I get about 1 or 2 ohm and at full I get 92 ohm the unit is a robbmc about 2 yrs. old. When I ground the power wire going to the unit the fuel gauge does go to empty. when hooked back up moving the float by hand the gauge moves from empty to full very smoothly but it only moves maybe 2 maybe 3 inches from the empty mark on gauge to full, and if I take the float up to full it reads about 3 o-clock.----BOB

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Old 10-19-2019, 01:31 AM
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You need to look at the ohms for the full range. You might have some bad spots on the wiper assembly. In that case, it could read the correct ohms at full and at empty but might jump all over the scale as you move it up.
You might be right that it's the gauge but I would do that check before condemning it.

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Old 10-19-2019, 11:17 AM
ELKHORNAOG7 ELKHORNAOG7 is offline
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Quote:
Originally Posted by Greg Reid View Post
You need to look at the ohms for the full range. You might have some bad spots on the wiper assembly. In that case, it could read the correct ohms at full and at empty but might jump all over the scale as you move it up.
You might be right that it's the gauge but I would do that check before condemning it.
When moving the float very slow the ohm meter moves very smooth btwn. empty and full with the meter at max. 92 ohms------BOB

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Old 10-19-2019, 12:31 PM
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Quote:
Originally Posted by ELKHORNAOG7 View Post
Anyone know a company or someone on PY that can rebuild a fuel gauge for a 68fb
Hey Bob,

PY member Peter Serio works on guages. He doesn't post much in street section so try sending him a PM.

Starting to sound like some varnish flaked off a magnet wire coil and recalibrated the guage.

Can't beat the price on the guage max 93 has. I wouldn't mind having it my self. Just to get ohm readings and use for a test guage.

Good luck and keep us updated on this oddity
Clay

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Old 10-19-2019, 01:55 PM
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I also have a Camaro gauge you could have if your just looking for a test gauge

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Old 10-19-2019, 03:55 PM
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Quote:
Originally Posted by Greg Reid View Post
You need to look at the ohms for the full range. You might have some bad spots on the wiper assembly. In that case, it could read the correct ohms at full and at empty but might jump all over the scale as you move it up.
You might be right that it's the gauge but I would do that check before condemning it.
Greg:---I did what you said and the float runs very smooth thru the full range and reads 92 ohms at full and when I hook the gauge back up move it where it reads full I get a reading of 31 ohms for full on the gauge and not 92 ohms when the float is lifted to full mark the gauge reads 3 o-clock that is why I'm leaning at a gauge ands not the sending unit even when the float is lowered to empty the gauge still will read 3 o clock until I ground it out to go back to empty----BOB

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Old 10-19-2019, 07:17 PM
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Yeah, that is sounding like a gauge problem.

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Old 10-20-2019, 06:57 AM
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Quote:
Originally Posted by ELKHORNAOG7 View Post
Clay: When I checked the sending unit out of the tank at empty I get about 1 or 2 ohm and at full I get 92 ohm the unit is a robbmc about 2 yrs. old. When I ground the power wire going to the unit the fuel gauge does go to empty. when hooked back up moving the float by hand the gauge moves from empty to full very smoothly but it only moves maybe 2 maybe 3 inches from the empty mark on gauge to full, and if I take the float up to full it reads about 3 o-clock.----BOB
Quote:
Originally Posted by ELKHORNAOG7 View Post
Greg:---I did what you said and the float runs very smooth thru the full range and reads 92 ohms at full and when I hook the gauge back up move it where it reads full I get a reading of 31 ohms for full on the gauge and not 92 ohms when the float is lifted to full mark the gauge reads 3 o-clock that is why I'm leaning at a gauge ands not the sending unit even when the float is lowered to empty the gauge still will read 3 o clock until I ground it out to go back to empty----BOB
These two post aren't painting the same picture. Or my interpretation of the first post is wrong. Second post says the sending unit will not move the gas hand back to empty but grounding the wire does. The "2 maybe 3 inches" from E to F in the first post wouldn't work if the second post is correct.

More ohm testing needs done on the sending unit if it wont force empty but grounding the tan wire does. There's some resistance there some where that's getting over looked or missed. Or possibly coming and going from a poor connection.

Need more testing or clarification with what's going on. Could be a problem with the ground wire since the rheostat appears to be in the right range.

Something just ain't right

Clay

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Old 10-20-2019, 01:18 PM
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Clay:---I will go thru all the test again to double check what you are saying but can't due it today (SUNDAY) due to rain and I'm outside so ( asap ) and repost my findings------BOB

  #16  
Old 10-20-2019, 05:11 PM
ELKHORNAOG7 ELKHORNAOG7 is offline
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Clay; ( Good eye ,,,,) I spoke to my son that was watching the gauge when I was testing and I was wrong about needing to hit ground to return to empty, he said that the gauge did read up and down with the movement of the float and would return to empty, but did only work within the 2 to 3 inches of float movement otherwise would go up to 3 oclock at full float travel.----BOB

  #17  
Old 10-21-2019, 07:59 PM
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Did check again today Monday and still the same as in post #16-----BOB

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Old 10-22-2019, 03:12 PM
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Definately sounding like something happened in the guage. Guage going to empty, while working the sending by hand, tells us the wire is good from the guage to the tank.

Not that many parts to the guage: few resistors and magnet wire coils. So sounds like something changed the resistance on one of the parts in the guage. Making it read 0~30 ohms instead of 0~90 ohms.

It'ld be nice to have a good guage just so you could compare ohm reading on the different parts and see what shorted or blew out. Be easy enough to change resistors....But I wouldn't really want to rewind the hair size wire in the coils. It'll break or the coating will flake off and it would change the calibration of the guage.

Keep us updated on what you find.
Clay

  #19  
Old 10-28-2019, 04:32 PM
ELKHORNAOG7 ELKHORNAOG7 is offline
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Talking Fuel gauge (( up date ))

TUES. 10/28/19 Put the new gauge in the dash after I put the tank back up, and everything works, so the old gauge turns out that it was bad. I would like to thank everybody for their help, and once again ( MAX93 ) for the replacement gauge.----BOB

  #20  
Old 10-28-2019, 06:52 PM
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Glad it worked out for you

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