What is the black tube like thingie that an electrical plug plugs into?

 

on the back of the intake that is.

 

On the back of the intake on the driver side is the EGR vacum regultor valve soleniod.

 

why do some cars have this and some dont? How important is this sensor?

 

Some owners have deleted their EGR system altogether. I no longer have mine due to some issues with my header install. It is part of the emission control system, but I passed without it. If you remove all of the associated parts, it is just a matter of getting some block off plates to cover the holes, and you're good to go.

I believe LT4 Corvettes did not come with EGR valves at all. They are good for something, but apparently they do not make that big of a difference.

 

It is used to reduce NOx emissions by recirculating some exhaust gas back into the intake. Some people that don't have emissions testing have blocked off/removed the EGR system, which is why you wouldn't find it on some LT1s.

 

Look at Shoebox's photo of the back of the manifold, and tell us which one it is. The EGR valve is a 3" diameter flying saucer shaped piece bolted to the rear of the plenum, and had NO wires connected to it, only the vacuum line. On the drivers side, on a bracket on one of the last intake manifold bolts, is the EGR vacuum solenoid - that has a connector on it. Neither of these are "sensors"... and they are required if you want a functioning EGR system.

Also on top of the block, right behind the intake manifold is the oil pressure sensor.... that would be considered a "sensor"....

http://shbox.com/1/egr1.jpg

 

Its the little black tube right below the egr valve...and also, the tube that plugs into the exhaust manifold.....looks nice in the pic, but I have mac shorties and it doesnt line up, so I am getting some exhaust leaks from it. I feel like removing it all but dont want to open up a can of worms if I need any of this crap.

 

I believe you are talking about your oil pressure sensor. To check if that is correct pull the plug and crank the engine, then check the oil pressure inside the car. If the low oil light comes on and your gauge doesn't give you a reading then thats what your looking at. Once you've done that simply plug the connector back in.

 

Yeah, that was teh one. Last night a friiend and I pulled the intake becuase it was leaking, and sealed it back up....I hit the sensor and broke it. I put everything together this evening and cranked the engine. The oil pressure guage was not working. i ordered an ac-delco and will replace it sat.

 

Hey man how hard was it to take the intake mani off? I plan on doing it sometime to get it painted.

 

easier than I thought, pop the bolts, get a happer with a 2x4 and tap it...comes right off.