Oil gauge issue

[Niagara Dave]

Hello everyone. I have had an issue with the oil gauge FF supplied. At first it stoped working when I came to a traffic light and the oil pressure dropped below 25psi. Then I started to bounce like it was possessed and now it will only work if the pressure is above 75psi. Is it the gauge or the sending unit? I am running a SBC old school gen 1. I installed the sending unit jus above the oil filter on the drivers side.

[JimLev]

Have you checked for loose connections?
The sender works on changing resistance as the pressure changes.
If you have a few resistors you could use clip leads to connect them to the sender wire and ground to see if the gauge is working.

75 PSI is pretty high for a SBC. My last one only ran around 50PSI (hot) at speed.

[TomH33]

I have built a bunch of small block chevys (as well as the 400ci in my 33). I have always mounted the sending unit next to the distributor on the block and thay all worked fine.

TomH33

[Niagara Dave]

Thanks guys. Tom do you have a photo of the location. It was never 75psi before. I do have a high volume pump on it.

[TomH33]

Here is the best photoI can do. You can use 1/8"NPT tubing or 45 degree fittings to make it fit under the distributor. 9301193012

Have more questions, just ask.

TomH33

[Niagara Dave]

Thanks Tom I am going to try that.

[wrp]

I had one go bad. And when I worked on replacing it I foolishly used thread sealer to ensure it didn't leak. What I accomplished was to avoid the ground necessary to make it work. Here are some shots of mine. I like the angled installation Tom did but mine had a short piece coming up form the block then two 90's to offset it. Has worked pretty good. Bottom line is what Tom says.

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[bakerboerne]

One thing I noticed with these gauges is that even if you use the push on connectors on the gauge you have to make sure the nuts are tight on the screw posts.