This one might be hard to troubleshoot from afar. simple 12 volt negative ground set up for my 31 Roadster. I am not running a ballast or a solenoid when I turn the key, the oil pressure gauge and water temperature gauges jump to the maximum reading. Everything else works fine incld interior lights, dash light, usb charger, fuel gauge and volt gauge. Any idea on why these two gauges immediately jump to the extreme? This occurs when I start the car and when I just turn the key to the accessory position. According to SW, they are wired correctly with brand new wiring. Entire car is brand newly wired. the gauges are new Stewart Warner. They worked previously.
Double check your wiring , usually both those gauges read by how much resistance to ground to get the reading. If your signal wire is shorted to ground it will do this. But it does seem odd that two gauges do it as they have seperate signal wires. But it is something to check and eliminate. Bones
Update: 1- bad oil sender 2- bad wiring to temp senders.... aka got bad advice on how to wire them issues resolved thanks fearless hambers
I'm going through this right now. GM ignition Key has two terminals that switch to ground on START. One wire goes to the OIL Pressure sender. The other I am trying to trace its location, but also appears to goes to the gage cluster. You mentioned the gages worked previously, Has this problem just occurred or is this trouble shooting new wiring?
It's a new problem associated with swapping my Banger for a Flathead so while doing the engine swap, I rewired the whole car.
Normally the wires that go to ground on start are there to ground a warning light circuit, turns the light on while cranking so you know it's working.
Do the gages indicate properly with the engine running or remain at Max ? Sounds like a Gnd problem, Check that the block has a good ground. Gages should not be powered on Acc., only in Start/Run. Check Ignition/key switch or wiring. Running an Alternator or Generator ? Pos Or Neg ground ?
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