SENSOR LOCATIONS:

[Stewart G Griffin]

Let's discuss the different sensor locations of the SBC:

1) Now, we know that the temp sender is located between spark plugs 1+3.

2) There is a single-pronged deal at the base of the distributor.  What is it?

3) There is a double-pronged deal just above the oil filter.  What is it?

If it is what i think it is(oil pressure senders), then why does the truck have two (at the base of the distributor AND above the oil filter) things plugged into EACH of the these locations if the truck only has a oil warning light and no oil pressure gage?

[123 pugsy]

#2 is the oil pressure.

#3 I think is the knock sensor

[VileZambonie]

The single wire is for the light/gauge.

The two wire is the oil pressure switch. Is your truck fuel injected?

[Stewart G Griffin]

No, it's carbed.

So, why are there two locations?

[VileZambonie]

What year is your truck? It's most likely for the electric choke then. You don't want the choke to come on with just the key on, just when the engine has been started. It also functions as a choke malfunction indicator on the instrument panel.  Here is some more info on the ckt for u.

On some models, the oil pressure indicator light also serves as the electric choke defect indicator. If Oil or ENG. indicator light does not light, check to ensure electric choke is not disconnected at carburetor. Also check for defect in electric choke heater, blown gauge fuse or defect in lamp or wiring circuit. If indicator light stays on with engine running possible causes are: oil pressure is low, switch to indicator light wiring has an open circuit, oil pressure switch wire connector has disconnected or on some models, gauge or radio fuse has blown.
The oil pressure warning light should go on when the ignition is turned on. If it does not light, disconnect the wire from the engine unit and ground the wire to the frame or cylinder block. Then if the warning light still does not go on with the ignition switch on, replace the bulb.
If the warning light goes on when the wire is grounded to the frame or cylinder block, the engine unit should be checked for being loose or poorly grounded. If the unit is found to be tight and properly grounded, it should be removed and a new one installed. (The presence of sealing compound on the threads of the engine unit will cause a poor ground.)
If the warning light remains lit when it normally should be out, replace the engine unit before proceeding further to determine the cause for a low pressure indication.
The warning light will sometimes light up or flicker when the engine is idling, even though the oil pressure is adequate. However, the light should go out when the engine speed is increased.

[Stewart G Griffin]

I.C.

It's an 83.

[Stewart G Griffin]

Is there only one way to plug this in?  Or does it not matter?  I think i may have plugged it (the wiring) upside down.

[VileZambonie]

Why do you think you pluged it in upside down?

[Stewart G Griffin]

Well, if you look at the sensor, the prongs are not actually centered in the circle;  They are a little off to one side.  When i took mine out, they were closer to the filter.  When i put it back in, i got it tight to the point where the prongs were closer to the top of the engine.  At the time, i didn't care because all i wanted was to get the engine ready to go back in the truck.

Come time to plug everything back up, i plugged the wiring harness in the same way as i unplugged it.  i was worried that this might be wrong because my oil/choke light would stay on whenver the engine was running.

Tonight, i unplugged it and flipped the harness over no real change in outcome.  Then i checked the fuse---and lo and behold it blew---presumably a few days ago when i ran the engine without everything completely hooked up.

Now, the light goes out and the choke seems to be working good.  So, i guess it doesn't really matter which way you hook it up or at least i'm not concerned anymore.

But thanks for the help because i would probably still be running the engine without that thing plugged in ASSuming that it had nothing to do with the choke.  And thus be still having choke problems.