Oil pressure sending unit

[rockinje]

I’m working on an ‘86 Sierra Classic with a 4.3 liter with an oil pressure gauge in the dash. It has 2 oil pressure sensors behind the distributor; one bell shaped with one electrical connection which I understand is used for a guage setup and the other is a longer “tube” shaped sensor with 2 electrical connections which I understand is for an oil pressure light in the dash( which I don’t have). Is this normal for this engine? My chilton’s manual says almost zero about the oil pressure sensor.

Any help is appreciated

 

[legopnuematic]

The second switch is for the electric choke.

That way the choke coil will only be energized when the engine is running and making oil pressure.

 

[rockinje]

Thank you, I learned something today.

JE

 

[grummy]

>>>My chilton’s manual says almost zero about the oil pressure sensor.

That is interesting because every old Chevy I had, the Oil Pressure Gauge always >showed< "almost zero" !
Lol !! I wonder if Chilton mis-worded things. But yes, smaller diameter switch allows for the choke to get power only when actually running and not just if the key is left on.

If your in there working, you might consider adding an actual gauge. My C15 with the 305's gauge never goes much above 20psi. I did just install a legit gauge back by the distributor and that shows 40 psi. Makes a guy feel a little better.

 

[rockinje]

Thanks Grummy, my gauge in the dash also shows about 20 psi….just got this truck recently and it needs A LOT of work…lots of original ‘86 parts that need to be replaced for reliabilities sake…. It’s a work in progress!

 

[YakkoWarner]

My stock gauge usually shows between 30 and 45 but not always sure if its really right or not because it doesn't seem to change with rpm. I have a small 3 gauge A pillar mounting with a mini tach and possibly more accurate pressure gauge but have not had the chance to (AKA keep the thing running long enough to warrant an) install.

 

[75gmck25]

My ‘75 GMC has a Goodwrench crate 350, purchased in about 2003, and the truck has the original in-dash mechanical oil pressure gauge. That means there is no electric sending unit to affect the reading.

At idle the oil pressure runs about 15-20 psi (depends on how cold it is), and pressure rises up with rpm, maxing at about 50 psi on the highway. I think this is just about what it should be for an engine in decent condition. I have a roller conversion cam, so I’m using 10w30 Mobile 1 synthetic oil.

 

[Ricko1966]

Thanks Grummy, my gauge in the dash also shows about 20 psi….just got this truck recently and it needs A LOT of work…lots of original ‘86 parts that need to be replaced for reliabilities sake…. It’s a work in progress!

Just replacing parts is no guarantee of reliability, a LOT!!! of new parts are not as good as the used parts they replace.