im going to install some non-emisions headers, but before i do that i need to know what should i block off or remove, all those smog deals.

if anyone has a link please post.

any info will be appreciated
thanks
michael

 

on what?

 

More specifics are needed on your car, model/year/engine.

 

sorry about that, but its a 94 z28 w/LT1 and a4 tranny

 

You'll have to remove the AIR pump and the EGR system. You will need some EGR blockoff plates when doing so.

 

Well the part number for the LT4 block off plate is: 10054880
But I just went on gmpartsdirect and it says it's discontinued. You might call your local dealers to see if they have one floating around.
They aren't that hard to make. You can just get an EGR gasket, trace the pattern and cut it out of a 1/4" sheet of aluminum or similar. I've heard of people using an aluminum can however I wouldn't trust that to be leak free.
If you block off the EGR side of the manifold you will not need a plate for the tubing side. There are two ports on the EGR side. One of them is plummed from the tubing side. If you block off both those ports on the EGR side the tubing side port becomes obsolete.
You will need to delete the EGR and AIR via tuning or you will get a SES light unless you want to at least leave them plugged in to the clip so you fool the PCM into thinking they are functioning. Be prepared for a very different sounding car. Especially w/ an off-road pipe.

 

For the EGR, you only HAVE to block off the small, diamond shaped port that the EGR riser tube connects to. Not necessary to remove the EGR valve, but if you do, you need a block off plate for that.

http://sjmmanufacturing.com

It is possible you will get a code for no EGR flow. OBD-I diagnostic is not very sensitive, but maybe 10-20% of the people who delete the EGR system get a code. It can be programmed out of the PCM.

Then you have to decide if you want to remove the EGR vacuum solenoid. When you remove that, it will definitely set a code. You can stick an resistor with the same value as you measure across the solenoid to fool the PCM. Then use a small (1/8" ??) vacuum cap to seal off the vacuum nipple on the side of the intake manifold.

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

For the AIR pump, no need to remove it, but you can. Simply disconnect the electrical connector, and make sure there is a good fuse and relay in the circuit, and you won't get a code (93-95 OBD-I only). Remove the hose that runs from the air inlet duct to the AIR pump, and cap the connection on the air inlet duct with a 5/8" vacuum cap. Physically removing the pump is optional. You will want to remove the hard lines, and the one that goes under the timing cover generally needs to be cut to be removed.