Delete it, the manifold sytle injection is redundant since there are provisions to inject air at the back of the heads. If you don't have emissions tests to pass delete the whole system but leave the TAB and TAD solenoids electrically connected to prevent a code. You can also remove the air pump but it's easier to just let it pump to atmosphere, it doesn't consume any engine power worth talking about.

 

cool...

I don't have any hook-ups at the back of my cyl heads.... So I'll just leave the tube open at the pump. Will it make any noticable noise when inside the cab?

 

im gonna have the same issue on mine when i do the headers , so i can leave the airpump connected, but evrything else going to it just remove? were are the tab and tad solenoids located?

 

Tab and Tad solenoids are under the coil, when doing this make sure there are no vacuum lines left open or holes in the exhaust system, if the motor does have air injection in the heads remove the crossover tube and plug the heads. You should not hear the pump from the drivers seat, but if you do simply connect the outlet directly to the muffler on the passenger inner fender.

 

im not familiar with this sytem at all,loL! is there anydiagrams online of the complete system so i can get a better understanding of it? whats the purpose of it? my truck is a 91 but prod date is 8/90. i know just by looking at it i have the metal tubes at the top of the manifolds which runs to the back of the motor from each side, can i just unbolt the 4 smaller tubes connected to the manifold then it goes into a single larger one in front of the coil on the drivers side and plug that?, same with the pass side? or do i need to plug it were it goes into the back of the motor, assuming it does havent actually looked back there yet.

 

The thermactor air injection system pumps air into the exhaust to help the cat burn off excess hydrocarbons. It's managed by the computer with valves so that it only pumps air in at the heads on cold starts, otherwise it diverts air directly to the cats or just dumps it back to atmosphere. It's needlessly complicated and can be simplified without impacting function or eliminated completely.
Any leak in the exhaust system upstream of the O2 sensor will cause drivability problems and potentially poor milage, so it's recommended you completely remove all plumbing and plug the heads, the holes are tapped for a standard coarse thread bolt.

 

well heres a pic of mine from underneath, the one tube is capped off, guess that went to one of the cats? the other small metal tube to the right has a hole in it, this is part of the air setup also correct?

 

Yep, and that's why you need to remove all this plumbing, those holes are allowing fresh air into the exhaust and messing up the O2 sensor readings.

 

My smog pump made noise pumping into the atmosphere. You only heard standing out front of the the truck, but it was annoying. I bent the intake side tube over and hooked it up to the output side of the pump. It was pretty quiet then. You can also gut the pump, but I suggest keeping it intact in case you ever need it. I ended up gut mine when the bearings got real loud.

 

ok, so after all the plumbing is gone, theres only 2 holes that will need to be plugged in the heads, 1 on each side were those metal pipes in the pic are running into?

 

Yep.. a couple bolts and copper washers will cap them off nicely..

 

Correct, go to the hardware store and get two 5/8" (7/16" thread) x 1" bolts and washer or two to put between each bolt and the head. I hit mine with some red loctite as well to make sure they stayed nice and tight.

 

cool thanks for the help!!

 

"Yep.. a couple bolts and copper washers will cap them off nicely.. "

Conanski y the copper washers? Because of the bi-metals?