Still having trouble
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Joined: Oct 2010
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From: Palm Desert California
Still having trouble
Converting mech oil pressure to electrical on my '73. Purchased new oil pressure gauge and sending unit for a '74 from Wilcox. Temporarily connected gauge at engine bay to make sure it worked before taking out the gauge cluster. According to willcox there is no resistor needed on this gauge (inside) . When starting the car the gauge goes to 80 psi and stays there and does not return to Zero when the engine is turned off. Performed the gauge check as per Willcox and it is ok, checked ohms at sender ( wire off ,car running) and got 90, not much of a reading when car is off. My old mech gauge read about 65psi when first starting and then settled at about 45-50psi after warm up . There is no change if the car is up to temperature. Any thoughts would be appreciated, maybe I'm missing something simple.
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Joined: Mar 2014
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I thought I took a pic of mine after I hooked it up, apparently not.
But at any rate here is my adventure shortly after buying mine. Slightly different because mine is a 74, however it fits what you are doing.
I was able to use the factory plug shown by Wilcox that was in the car. I just used a wiring terminal to (plug in) each wire. (for now)
Sending unit wire (I chose to run a new one for the time being) power wire was good.
The ground I ran to the back of the gauge cluster.
That would be the first suspect for me in your case. Used to do it a lot, now I can't remember if grounding the gauge will spike it max, or low. But the ground will make a big difference.
Yes you do not need the resistor on the out side of the gauge.
Where did you put the sending unit?
I did have to bend the connection down (90 degrees) on mine to plug it in. But like the one pictured it is in the same spot.
At any rate here is my thread.
https://www.corvetteforum.com/forums...g-adapter.html
But at any rate here is my adventure shortly after buying mine. Slightly different because mine is a 74, however it fits what you are doing.
I was able to use the factory plug shown by Wilcox that was in the car. I just used a wiring terminal to (plug in) each wire. (for now)
Sending unit wire (I chose to run a new one for the time being) power wire was good.
The ground I ran to the back of the gauge cluster.
That would be the first suspect for me in your case. Used to do it a lot, now I can't remember if grounding the gauge will spike it max, or low. But the ground will make a big difference.
Yes you do not need the resistor on the out side of the gauge.
Where did you put the sending unit?
I did have to bend the connection down (90 degrees) on mine to plug it in. But like the one pictured it is in the same spot.
At any rate here is my thread.
https://www.corvetteforum.com/forums...g-adapter.html
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Joined: Mar 2014
Posts: 73
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I will add after reading my thread again.
This is what I have been doing for several years. Now on the newer fancy stuff.
It gets interesting when you are looking for a part, or just trying to figure out how the wires are routed.
How did you wire the gauge?
Sending unit to one post, 12v to the other, ground to the 3rd?
If not that is your problem.
Look at the diagram Wilcox posted in my thread.
This is what I have been doing for several years. Now on the newer fancy stuff.
It gets interesting when you are looking for a part, or just trying to figure out how the wires are routed.
How did you wire the gauge?
Sending unit to one post, 12v to the other, ground to the 3rd?
If not that is your problem.
Look at the diagram Wilcox posted in my thread.
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Joined: Oct 2010
Posts: 695
Likes: 55
From: Palm Desert California
Sensor is mounted at oil port under distributor, finally just ran a wire from the gauge to the neg battery connection at the frame to ensure a good ground. Just thinking , if the sensor is reading 90 ohms with the wire disconnected and engine running wouldn't that make the gauge read 80psi ( full range) ? Maybe I'm chasing my tail and the gauge is reading correctly. But that doesn't explain why my mech gauge read what seemed to be accurate. Think I will hook up a pressure gauge directly to the oil port tomorrow and see just what pressure I do have. Thanks for your response.
Thread Starter
Pro
Joined: Oct 2010
Posts: 695
Likes: 55
From: Palm Desert California
I will add after reading my thread again.
This is what I have been doing for several years. Now on the newer fancy stuff.
It gets interesting when you are looking for a part, or just trying to figure out how the wires are routed.
How did you wire the gauge?
Sending unit to one post, 12v to the other, ground to the 3rd?
If not that is your problem.
Look at the diagram Wilcox posted in my thread.
This is what I have been doing for several years. Now on the newer fancy stuff.
It gets interesting when you are looking for a part, or just trying to figure out how the wires are routed.
How did you wire the gauge?
Sending unit to one post, 12v to the other, ground to the 3rd?
If not that is your problem.
Look at the diagram Wilcox posted in my thread.
