Have a "Rally gauge, volts and oil" on my GT by previous owner. The oil pressure gauge is erratic..when you start its at 40psi, swings all the way right off the face, then back and forth to 40, like a short "". Also, have the face off the rally gauge but cannot puull the volt/oil gauge unit out. Any ideas ?? Could use a diagram / pictures of this " rally gauge" set up

Sender or plug to it is likely "dead."

See my Cave, Oil Sensor

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Oil pressure sending unit or wiring is more likely faulty than gauge itself.

You have to remove radio/heater trim plate and loosen radio surround to remove gauge cluster.



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[This message has been edited by fierosound (edited 07-28-2020).]

quote Originally posted by fierosound: Oil pressure sending unit or wiring is more likely faulty than gauge itself.

With my Formula, a pegged (to the right) oil pressure gauge was simply a loose connection at the sender. T'was a ten second repair job.

Thanks guys for your input. I also suspect a wiring issue. Question ?..where 0n a 85 Gt V-6 is the oil pressure switch ?? Looked in all the manuals and could not see an illustration. Lastly, what is the NORMAL operating PSI of the oil pressure.

quote Originally posted by 85fieroguy: what is the NORMAL operating PSI of the oil pressure.

See my Cave, Oil and Filter

quote Originally posted by 85fieroguy: Thanks guys for your input. I also suspect a wiring issue. Question ?..where 0n a 85 Gt V-6 is the oil pressure switch ?? Looked in all the manuals and could not see an illustration. Lastly, what is the NORMAL operating PSI of the oil pressure.

Non A/C car has it down by oil filter.




A/C car has tube relocating it near front of head.

[This message has been edited by fierosound (edited 07-29-2020).]

I got rid of that ac setup and just went with the 88 style sender. I mounted it down low so it is no longer an eye sore.