Local oil pressure gauge?

[glockholiday]

88' Suburban TBI 350 A couple of years ago the previous owner replaced the oil pressure sending unit because it was leaking. The oil pressure has always run 45-60 on cold start and 30-45 when hot. I've never seen it under 30psi. Yesterday while idling the gauge slowly dropped from 30 to 0-10. I watched carefully and the pressure did not change when i took off from the stoplight. I pulled over, everything was good, level full no leaks, no engine noise. On restart it came back up to 30, while driving home with the cruise on at a steady 1600rpm for miles the gauge went from 30 to 0-10 again. So now I'm pretty sure it's the sending unit or gauge, I've driven 50 miles since it first happened and it's oviously still got pressure. Oil warning light never came on. Sending unit is easy but if it's the gauge how does that get fixed.

Is there somewhere else on the engine I can add a local gauge to read under the hood, other than adding a T fitting to the sending unit?

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[Honky Kong jr]

Put a mechanical gauge in it. I have my factory gauge wired so it’s a pressure no pressure. If it goes below 20 psi it reads 0. The I have a mechanical gauge as well.

 

[glockholiday]

So just buy one off amazon? Where do I install the pressure line? Am I right that my truck has 2 sensors one for the gauge and one for the dummy light and fuel pump relay?

This is the one by the oil filter, and I guess there's one up by the distributer?

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[hatzie]

Tee into the port behind the intake manifold. It's 1/8" NPT. You can get brass 1/8" NPT fittings from the Hillman drawers at a real hardware store.

 

[bucket]

There's no dummy light.

I'd put a mechanical gauge on it ASAP. An SBC only needs a few lbs of pressure to keep from knocking, unless you are working it hard.

 

[Honky Kong jr]

And don’t use that stupid plastic tubing get a roll of copper tubing.

 

[glockholiday]

There's no dummy light.

I'd put a mechanical gauge on it ASAP. An SBC only needs a few lbs of pressure to keep from knocking, unless you are working it hard.

I was mistaken. I agree, no dummy light, so then is the sensor up by the distributor a oil pressure go-no-go just for a fuel pump signal?

 

[bucket]

I was mistaken. I agree, no dummy light, so then is the sensor up by the distributor a oil pressure go-no-go just for a fuel pump signal?

Yeah. It triggers the fuel pump when the pressure builds up, in the event of a fuel pump relay failure.

 

[glockholiday]

What about this plug above the oil filter that could be removed with the square drive of a 3/8 ratchet? I have access to plenty of fittings to add a mechanical gauge and would rather not T into the other sensors if I could have a dedicated source. Is this plug upstream or downstream of the filter, is a spring going to pop out on me?

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[glockholiday]

OK it was the sending unit above the oil filter. Replaced it and pressure is reading normal again.

I'd still like to know what the square drive plug is for on the oil filter housing I'm still thinking of adding a mechanical gauge.

 

[bucket]

I looked at one of my adapters yesterday, that plug went right in where a bypass valve is.

I really would want to tee it in at the port by the dizzy. That way the pressure line for the gauge will be out of harm's way.

 

[Honky Kong jr]

X2 on the Tee at the distributor