Electrical Gremlins???

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mpbsr

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First, let me say something that we all know....These cars are like an expensive mistress.

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Not sure if it would matter to the problem, but about 2 months ago, I upgraded the intake and added a Holly 600 4bl.

I also only take "Christine" out for a drive about twice a month during the spring through fall season.

About 3 weeks ago, I noticed that the Oil Pressure gauge was a little on the high side, but I did check the oil after Christine sat a while and all was fine.

Heading out for a later drive this evening and the Oil Pressure was again a little on the high side, but ok as I kept on eye on it. Started to get a little dark so I put the lights on. Within 15 secords the Oil Pressure went even higher and now the Temp Gauge also went higher. I turned the lights off and both gauges came down a little. Of course when I got real close to home I put the lights on again and both gauges went up.

I really can''t imagine that the actual temp went that high because of the lights on or even the Oil Pressure.

Thoughts???

Thanks

 

Vicus

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Have had the same problems two years ago.

cause: bad ground of the engine due to corrosion under contact area.

solution: remove the oxide film and renew the ground cable from engine to chassis.

Cheers

Frank

 

Bill73Ragtop

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former owner (25 yrs) of 1973 Convertible, 351c, A/C, RA
I've lived with the same condition for years. Cleaning and ensuring all the ground connections is the first order of business and will lessen the increase in gauge readings (although nothing has changed insofar as real oil pressure and temperature). Hours of measuring voltage, amps, changing voltage regulator to electronic, etc to find the exact source of the issue basically got me nowhere.

I also added a ground strap from the rear of the block to the firewall. So now when I turn on the headlights, the gauge needles move up maybe 15-20% and I live with it since it does not seem to be having any deterimental effect on anything else.

 

Don C

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I would suspect the ground to the printed circuit. The dash lights coming on would change the impedance to the circuit board in the case of a dirty or corroded ground or connector.

 

mpbsr

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I appreciate everyone's responses.

Just to add something else as I realized this morning.

I also changed the spark plug wires (making sure that they're secure and added dielectric grease) and the distributor cap.

While driving home I also noticed a very slight miss every few minutes, but everything including the slight miss only happened on the way home after driving for about 1/2 hour and the car sitting for about 1/2 hour.

Thanks again.

 

mpbsr

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Got Christine back today.

It was the ground strap that became loose and voltage regulator that went bad.

All is fine now....until the next time.

 

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