Gauges recalibration?

Charging, starting, lighting, gauges, HVAC

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jgf100
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Gauges recalibration?

Post by jgf100 »

My '70 f100 was sitting for a while due to accident but now is up an running. I noticed that my gauges were not working correctly. The fuel sender only goes to 3/4 when full, the amp gauge looks to be ok, the water and oil pressure are not working either. I replaced the voltage regulator on the dash circuit so I know that is not the problem. I also checked that gauges are working by grounding the sending wire and the needle moves fine. Do the gauges need to be calibrated, reset after sitting for a while? If not, what could be issue.
'70 F100, 302 C4
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basketcase0302
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Re: Gauges recalibration?

Post by basketcase0302 »

Calibrate the gas sender at full tank.
If the new instrument panel voltage regulator doesn't have an adjustment screw on it, (last one I bought from DC did) you can bend the rod on the sending unit itself to compensate/calibrate to read full. :wink:
Jeff
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MadMike
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Re: Gauges recalibration?

Post by MadMike »

jgf100 wrote: the water and oil pressure are not working either.
Those two components along with 'start' ignition coil power are on the same harness that connects via a three pin bullet connector, one male two female connector. IIRC it's behind the dash cluster. Not to be confused with the three all female accessory power connector that is for ancillaries. Water and Oil wires then continue up to dash cluster connector.
Verify that connectors are properly connected clean and tight.

If an aftermarket ignition system, or electronic ignition was installed then the wiring may have been bypassed for the ignition. If so then then the Oil/Water/Start circuits may still be damaged, connected improperly or in need repair.

If sheet metal was removed/repaired, verify that the grounds/bonding jumpers were installed correctly.
Verify all connections are clean and tight. Some conductive grease to promote conductivity.
Battery to block.
Alternator to Voltage regulator.
Engine to cab bonding jumper. Braided. If this one is missing or loose the gauges may not work properly.
Cab to frame grounds are usually hidden by the inner fenders.

Don't rely on body assembly bolts to be good grounds, cept for the bed to frame, that should be good enough, but adding a jumper for the taillights wouldn't hurt.

One other note. When turning key to 'START' at prove out, the BRAKE warning lamp should illuminate.
If it does not, you may want to inspect the ignition switch/harness to the switch for good conductivity.
-Michael
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jgf100
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Re: Gauges recalibration?

Post by jgf100 »

MadMike wrote:
jgf100 wrote: the water and oil pressure are not working either.
Those two components along with 'start' ignition coil power are on the same harness that connects via a three pin bullet connector, one male two female connector. IIRC it's behind the dash cluster. Not to be confused with the three all female accessory power connector that is for ancillaries. Water and Oil wires then continue up to dash cluster connector.
Verify that connectors are properly connected clean and tight.

If an aftermarket ignition system, or electronic ignition was installed then the wiring may have been bypassed for the ignition. If so then then the Oil/Water/Start circuits may still be damaged, connected improperly or in need repair.

If sheet metal was removed/repaired, verify that the grounds/bonding jumpers were installed correctly.
Verify all connections are clean and tight. Some conductive grease to promote conductivity.
Battery to block.
Alternator to Voltage regulator.
Engine to cab bonding jumper. Braided. If this one is missing or loose the gauges may not work properly.
Cab to frame grounds are usually hidden by the inner fenders.

Don't rely on body assembly bolts to be good grounds, cept for the bed to frame, that should be good enough, but adding a jumper for the taillights wouldn't hurt.

One other note. When turning key to 'START' at prove out, the BRAKE warning lamp should illuminate.
If it does not, you may want to inspect the ignition switch/harness to the switch for good conductivity.
Good Advice, will check on all grounded connections. One question, "Engine to cab bonding jumper", where is this located?
'70 F100, 302 C4
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