Hey all. I have this thing on the back of my engine I don't know what it is, Can anyone help?

What does it plumb into? Oil? Vacuum? I think the older SBC has an oil pick up there. It could be the oil pressure sender/switch. But don't take my word for it, I own a '91 and don't have anything in that location.

Lou

it has a tube on the end of it going down the back of the engine, i can't see where it goes tho

Going down the back of the engine...tranny vacuum? 700r4s don't run on manifold vacuum do they? Maybe it's some kind of anti-smog device from Down Under, just kidding.
I've never seen anything like that before. I'll check Chiltons and let you know.

Well dude, I've looked through Chiltons and can't seem to find anything like that. The nearest thing I could come up with is IAC valve or EGR. Must be some kind of emissions device. Surely somebody on this site knows what it is?

I would say no to vacuum, no to smod device, no to EGR or IAC.
You could post it in the forum appropriate for your engine, I believe you'd get more answers there.

What wire colors does the connector have?

Lou

I will have a look at the wires when i get home and ill try get a better picture of it, it is plastic with a metal cap over one end that goes into a pipe then down the back of the block the other end has a plug with wires coming out of it.
It is about 100mm (3.9") to 130mm (5.1") long (just guesing coz im at work atm) it is about 50mm wide and its round, it tapers to about 20mm at the plug end.

The three wires are Yellow, Brown and black.
After having a closer look and feel it actualy goes into the top of the block just behind the intake manifold, it also has INTROL printed in small letters on the side of it (they are hard to read so cant be 100% that is what it sais).

You might want to unplug it with the engine running and see if any indicators on the dash light up or if gauges stop reading. My thinking still is that it's the oil pressure sender or switch.

Lou

I also think that it is the oil pressure sender or switch. If you lighten up the pic and look close at the left side it screws into the brass 90 that comes out of the block behind the dizzy.
Randy

It is the oil pressure sender. On my 85, the little brass tube that screwed into the 90* to hold it up and sideways started to leak and drop oil down the back of my engine. Had to remove it and run a bolt in the hole. My pressure gauge has not worked since. When swapping intakes be careful of the little brass tube, there are no replacements for it. I looked everywhere, if you damage it you either have to get creative or cap it off and find another place to reference oil presure. The intake manifold seals right in front of the hole, so even a after market sender can't screw into it because the back edge of the intake is in the way. Probably why GM used that little tube to lift it up and a 90* to kick it sideways.

Where do the other models and years reference oil pressure. Mine is a 85 Berlinetta from Van Nuys.

Ah cool, Thanks Lil Bastard.
I may move it if I can find somewhere better to mount it.
Would it be acurate if i mounted it on the firewall with a high preshure hose going to it? if it is evan that acurate to begin with.

EDIT: wait i thought the little switch on the lower LH side of the block (near the starter motor) was the oil preshure switch/sensor? coz when i disconected that plug my oil preshure gage died then it worked once it was pluged back in.