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Discussion Starter #1
Today I noticed my gauges are wandering. Fuel wanders 1/8 tank, oil pressure wanders 1/2 division, ammeter wanders a little, temp wanders a little. It cycles every 4-5 seconds on city streets and freeway.

Alternator is a 6yr old rebuild, regulator is a 6yr old solid state Bluestreak, battery is a 6mo old Optima. I replaced my IVR, but didn't adjust it.

I haven't done any troubleshooting yet, not quite sure where to start.

[color:blue]
1967 Acapulco Blue coupe
302 4V, C4, 9" 3.25:1
Torq-Thrust "D" 225-60-14
1968 PDB, Corbeau
LeCarra, Alpine in-dash CD
http://www.geocities.com/mlnielsen_67/index.htm
WEBSITE UPDATED 3/25/01
</font color=blue>
 
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If all of the gauges are fluctuating at the same time, I would suspect the wire supplying power to the instruments. Maybe corroded or loose? Not really my expertise here but that's where I'd start.

http://usn.tripod.com/mustang.GIF

"Sometimes a man's life can depend on a mere scrap of information."-The man with no name
 

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Bad instument voltage regulator??? It is mounted on the back of the instrument cluster. Also check it's grounding, it is grounded via the mounting screw, make sure there is clean metal where it touches and the screw is tight.

68 GT500
68 1/2 CJ Coupe

MCA# 18519
 

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Its the voltage regulator for the instrument cluster. Pull the cluster and you will find it attached to the back of it. It is a crude device that apears to work on a bimetal heater principal. John

It would be a shame to have passed the test but to have missed the lesson.
 

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Discussion Starter #5
I replaced the IVR with a repro unit from NPD. The dash has a fresh coat of paint, so I'll check the grounds.

[color:blue]
1967 Acapulco Blue coupe
302 4V, C4, 9" 3.25:1
Torq-Thrust "D" 225-60-14
1968 PDB, Corbeau
LeCarra, Alpine in-dash CD
http://www.geocities.com/mlnielsen_67/index.htm
WEBSITE UPDATED 3/25/01
</font color=blue>
 

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Ammeter gauge does not operate off the IVR. Thus this does not fit with the IVR as the symptom. But your clues sure sound like that's it on the others. Get a voltage reading of the IVR input and make sure it's constant.
 
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I cussed that ground for weeks before finding it loose. It's located right behind the speedo. Good luck

66 Pony Coupe, auto, 289
 

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Discussion Starter #8
I'll have to check all my Vs. I need to get an analog voltmeter. Fluctuating voltages are difficult to see on a digital VOM.

[color:blue]
1967 Acapulco Blue coupe
302 4V, C4, 9" 3.25:1
Torq-Thrust "D" 225-60-14
1968 PDB, Corbeau
LeCarra, Alpine in-dash CD
http://www.geocities.com/mlnielsen_67/index.htm
WEBSITE UPDATED 3/25/01
</font color=blue>
 
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