I'm considering a 73 coupe. Seller tells me the only temp gauge is working. Before I drive several hours to inspect it, I'd like some idea of the potential cause. I'm thinking something as simple as a bad ground. On the other hand, I can see spending hundreds on wiring harnesses and dozens of installation hours. Wiring is not my strong suit. I tried a search with C3 in the search box but 95% of the answers weren't from the C3 forums.

 

Oil pressure your that year does not have an electric sender...so who knows what is not allowing it to work.. They may have the port capped off. I am MORE WORRIED about this gauge not working. Not knowing what the oil pressure is.... is CRAZY!!!! I know I would have to install a oil pressure gauge to see what the oil pressure is BEFORE I would buy it. regardless if I do not hear any issues in the engine while it is running.

There is a port on the top of the engine at the back on the drivers side just behind where the intake seals to the engine block and this port is where you can attach an oil pressure gauge.

There is another port above the oil filter area that can allow you to do the same thing but the pipe threads for it are different and larger. So a brass adapter fitting needs to go in there to attach the oil pressure gauge fitting.

IF you do this and install an aftermarket oil pressure gauge. The oil pressure when the engine is cold will be higher than if you take it out for a good drive and get it HOT. I am more concerned about how the oil pressure is when it is at operating temp than when you just crank it up.

The fuel gauge uses the same power as the temp gauge....so you Amy have an issue in the fuel sender. No way in knowing until you get into the gauge cluster and take some readings.

The ammeter is what it is and the two wires going to it must be checked .

The clock is a 'no brainer' and can be checked when you get the gauge cluster out.

I know you said tat electrical is not your strong suit...but this is easy as long as you get a wiring diagram and are willing to expand your knowledge.. Having a volt/ohmmeter is needed also. And we can help you through this but it will take some effort from you and you getting some tools to do it....if YOU want to.

I am not gong to say if you need to buy wiring harnesses or not. So much depends on how bad the wiring looks and if you can tell if someone has been slicing and dicing on the wiring for their own DIY repairs. I can tell instantly if someone has been messing around doing wiring repairs due to most people do not do it right. They find whatever method fixes it fast.

DUB

DUB

 

Dub, thanks for the reply. Knowing its a 45 year old driver, I expect to spend some money on maintenance, if for nothing else to give me a base line. Neither the tac or the horn work. The seller has done a few things to get it ready to sell, replaced a leaky PS line, new cooling line to the trans. I wonder why he hasn't pursued the gauge problems. The underhood wiring along the firewall is a rats nest, making me wonder what else is half assed.

 

Then I guess it is up to you if you want to take the chance and buy it or not depending on the price it is being sold at...and what you feel it may take to get it to where you feel good about it.

I know people bring the Corvettes they plan on buying to my shop so I can inspect them and in many cases they are good...but in some cases I tell the buyer to run from it because they will get so upside down in the costs of what it will take to fix it versus what the car could ever be sold for again. And I am looking at these cars so they can be a good reliable street driven car.

DUB