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Discussion Topic:
gas guage problem
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missouriron |
03-13-2019 @ 11:28 AM
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Member
Posts: 27
Joined: Jun 2011
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My gas gauge reads full all the time while traveling. If I turn the key to 'on' and wait a minute or so, the gauge seems to be accurate. However, after getting on the road the gauge always goes to full. I have changed the sending unit and still have the same result. Any ideas?
Ron
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MG |
03-13-2019 @ 11:33 AM
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Senior
Posts: 1254
Joined: Nov 2009
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What year car? Original sending units?
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trjford8 |
03-14-2019 @ 7:40 AM
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Senior
Posts: 4214
Joined: Oct 2009
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Need to know the following; year of car, 6 volt or 12 volt, original gauge, original sender, is sender properly grounded. All this info would help to diagnose the problem.
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37RAGTOPMAN |
03-14-2019 @ 8:57 AM
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Senior
Posts: 1958
Joined: Oct 2009
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How is the wire, running from the FUEL gauge to the sender,? old and frayed ?bare spots,? sounds like it is grounding out somewhere. along the line, how old is the wiring harness, original or repro, my 2 cents, 1937 RAGTOPMAN I would disconnect the battery, disconnect the wire from the gauge and to the sender and use a ohm meter , on on each end, to test the circuit see what is going on, if does not read continuity , there is a break along the way, shake the wire, see if it changes. and it might be grounding before the sender, on the frame or else where, know how old and what car year,? the MORE INFORMATION, is needed for sure, hard to DIAGNOSE a problem with out a little history, if you need a wiring harness, I recommend RHODE ISLAND WIRING,comes with instruction diagram, exact same size wiring, and most important is ALL ends SOLDERED not just crimped
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missouriron |
03-14-2019 @ 5:54 PM
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Member
Posts: 27
Joined: Jun 2011
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Yeah, I should have given more info. 1951 Deluxe, 6-volt, new wiring harness from Tyree Harris. Sending unit is repro from Dennis Carpenter. When I turn the key to the 'on' position, the gauge seems to be accurate. At least reasonably accurate. When I start the engine and run it down the road the gauge pegs beyond the "F" marking on the gauge. I had to adjust my voltage regulator to 7-volts in order to make the overdrive solenoid engage. I haven't checked to voltage at the gauge with the engine running. That might be something to check. I have checked the wiring for shorts. Nothing weird showed up. I have taken the sending unit out and grounded it to the tank and moved the float with my finger. The gauge moves with the float level. Hope this helps. Ron
Ron
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TomO |
03-15-2019 @ 7:18 AM
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Senior
Posts: 7250
Joined: Oct 2009
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Ron,the voltage regulator should allow the generator to deliver 7.2 - 7.6 volts to the battery. It should be adjusted with a test set or on by a generator repair shop. That said, unless your voltage goes above 8 volts, it should not affect the gauge readings. The aftermarket sending units are resistive type units and are not as accurate as the original units, but if you have less than a half of tank and the reading is above full, the sending unit is shorting out. If this only occurs when the tank is over 1/2 full, it could be that the float is binding on something in the tank. A short to ground would make the gauge read above full. When you changed sending units, were both of them aftermarket? Tom
This message was edited by TomO on 3-15-19 @ 7:28 PM
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missouriron |
03-17-2019 @ 6:19 PM
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Member
Posts: 27
Joined: Jun 2011
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Yep, both replacement sending units are Chinese repro units. Another things that happened recently is the gauge was reading a little above 1/4 tank. I thought that it was finally working correctly. I ran out of gas. Is there a source for a good sending unit? Ron
Ron
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Drbrown |
03-17-2019 @ 7:26 PM
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Senior
Posts: 570
Joined: Nov 2013
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IMHO only an original NOS or rebuilt one is likely to work correctly with a stock gauge. Still have your original ?
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TomO |
03-18-2019 @ 6:35 AM
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Senior
Posts: 7250
Joined: Oct 2009
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If you have a reproduction tank, you are pretty well stuck with the aftermarket sending units. Are you sure that the float is not binding on the tank sides or baffle?
Tom
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missouriron |
03-19-2019 @ 3:54 PM
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Member
Posts: 27
Joined: Jun 2011
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No, don't have an orginal. Might find one in salvage yard somewhere.
Ron
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