Does anyone know what this is

[Burban1990]

Does anyone know what this is and do they have a tendency to leak oil? It's a Chevy 350 TBI engine. Never had a Chevy engine that didn't leak oil, this one's pretty tight but it seems to have a slight drip from this part.

You must be registered for see images attach

 

[Vbb199]

LH side is an 02 sensor


Next to that appears to be a oil pressure sensor.

Thats non OEM equiptment (the oil pressure sensor)

Factory oil pressure sensor is behind the distributor,

Standard oil pressure sensor is behind distributor, on top of motor, and has i believe a 4 pin plug in it.

 

[wanderinthru]

Does anyone know what this is and do they have a tendency to leak oil? It's a Chevy 350 TBI engine. Never had a Chevy engine that didn't leak oil, this one's pretty tight but it seems to have a slight drip from this part.

You must be registered for see images attach

That is the oil pressure sending unit. For some reason GM found some reason to get them harder to get to with the TBI???

Edit to change, sensor to sending unit. Hate sensors!!

 

[Burban1990]

That is the oil pressure sensor. For some reason GM found some reason to get them harder to get to with the TBI???

Thank you!

 

[Burban1990]

LH side is an 02 sensor


Next to that appears to be a oil pressure sensor.

Thats non OEM equiptment (the oil pressure sensor)

Factory oil pressure sensor is behind the distributor,

Standard oil pressure sensor is behind distributor, on top of motor, and has i believe a 4 pin plug in it.

Thank you for the response. Why would they run two of them?

 

[Vbb199]

Thank you for the response. Why would they run two of them?

Probably for the aforementioned reason its a PIA to reach in tbi.
Its behind the distributor, between the firewall and the engine....
Sucks to have to change out.

 

[Burban1990]

Probably for the aforementioned reason its a PIA to reach in tbi.
Its behind the distributor, between the firewall and the engine....
Sucks to have to change out.

So is it safe to assume they just blocked off the factory location?

 

[Vbb199]

So is it safe to assume they just blocked off the factory location?

Ya, it would be pissing oil everywhere if they didnt.

 

[Turbo4whl]

So is it safe to assume they just blocked off the factory location?

Both locations are factory oil pressure locations. Over the years different models have used either or even both locations.

When the block is cast the oil pressure galleys are drilled in. Then cross drilled to move the oil through the block.

 

[wanderinthru]

I don't believe your TBI will have one behind the dist, mine don't?

 

[Burban1990]

Both locations are factory oil pressure locations. Over the years different models have used either or even both locations.

Why would two locations be used at the same time? If that's what you mean by
"Or even both locations". Doesn't make much sense..

 

[wanderinthru]

Both locations are factory oil pressure locations. Over the years different models have used either or even both locations.

When the block is cast the oil pressure galleys are drilled in. Then cross drilled to move the oil through the block.

How would they use both? Or are you saying it could be found in either/or one of the 2 locations in a model? This is an honest question, please take it that way.

 

[Ricko1966]

They have used both at the same time, in different applications for example 1 for a gauge And one to turn power on and off to the electric choke or like I have done, 1 for the gauge and 1 to turn my electric fuel pump on and off, and or an electric cooling fan. You can control power side of multiple items with toggles, KOEO power, etc. ground them all to a relay using o.p. switch as a switched ground.

 

[Turbo4whl]

Why would two locations be used at the same time? If that's what you mean by
"Or even both locations". Doesn't make much sense..

How would they use both? Or are you saying it could be found in either/or one of the 2 locations in a model? This is an honest question, please take it that way.

Richard, @Ricko1966 answered your questions. In some models with an electric choke, would use the second location for a pressure on/off switch. This was done so if you just turn the key on for a while and not start the engine, the choke remains closed.

There is another oil galley plug in the back of the engine behind the flywheel. This is also there to close the cross drilling that runs the oil to the front of the engine. If you were overhauling the block and dunking it in the hot acid tank, you would want to remove all the plugs. Don't forget to put that one back in before installing the engine.

Many older small block engines in cars used the lower port for the pressure sender.

 

[Vbb199]

I don't believe your TBI will have one behind the dist, mine don't?

I havent seen an 87-91 fuel injected truck that didnt (unless someone moved it, or its a 454 tbi.)
Obviously i havent seen them all

Theres a yellow, orange, and tan wire going to the unit. Thought a white one also and the harness only stretches so far.