lostforawhile
06-22-2005, 01:10 PM
I've been seeing a lot of misinformation about these carbs and control systems on the site and for the sake of making life eaisier want to clear a few things up. some of you guys probably already know these things but for those that don't listen up. first of all there seems to be some debate on the idle screws. the idle screw IS the big black screw under the choke, it's not the fast idle screw,it's not the mixture, it is simply a jackscrew that goes through a casting on the bottom of the carb and the other end acts on the throttle shaft assembly turn it in the direction where it compresses the spring and it causes the primary to open other way it causes the primary to close. second there is no primary mixture screw. the only mixture screw is for idle mixture. the mixture is controlled by the computer it is not adjustable. more on that in a minute, third the adjustment that everyone thinks is the idle, the one on the left side of the carb,that is an idle controller for the computer the computer can raise the idle when nescessary. fourth all the controls that everyone thinks are just emissions those are actually part of your carb. how this system actually worksis that the carb is set at the factory with a rich mixture the computer uses various inputs through the oxygen sensor,the airjet controller,some cars have a barometric pressure sensor under the fender, load that is on the engine, output from the speedometer,and various tempreture sensors. it takes this information and injects air into the intake manifold through those two big white valves on the left side o the engine. these are controlled by two valves that open andclose at high speed and are directly controlled by the computer. those two valves are called the frequency solonoid valves and are in the black box. what this does is precisly control the air fuel mixture under different operating conditions. thats why it's called a feedback carb. sounds like fuel injection doesn't it? well now you have an idea how it works. hopefully this will clear up some confusion. :werd:
There is only one actual vaccume line on the air cleaner,the one that conects to the air door assembly it goes to number eight on the hard lines. if you are going to not have an air door you just cap off number eight hard line. all the other lines on the aircleaner are for supplying clean air to various valves on the engine. they are not vaccume lines! if you block them of you are going to have problems. they use the aircleaner like a big breather. if you don't have an air door you do not need the bleed valve or the check valve on the bottom of the air cleaner. they are conncted together and to the air door motor. once you block off number eight,they don't do anything. the only thing they normally do is control the airdoor motor in the aircleaner. that bleeder in the bottom of the aircleaner is nothing but a thermostat for the airdoor. all the other lines need to connected to the new air box or tube somehow. if you look in the bottom of the original air cleaner,you'll notice that they are just open. they are not supposed to be connected to each other. they feed clean filtered air to other things. the great big plastic tube from the bottom of the aircleaner is really important to have clean air. it goes to the box behind the valve cover. what this box is is a distribution point for clean air to the carb solonoid valves and other things. one end of it has the reed valve attached to it,this is the box with the tube that goes to the exaust manifold. all this does is let pulses of clean air into the exaust,this makes the converter work better. there is a peice that goes between the original aircleaner and this box,it has a wierd piece sticking out the side of it,this is nothing but a tube with a muffler in it.you don't need to use this piece,you can just use normal rubber tube to connect this to the new aircleaner.
got to recomend a chiltons book part #6980 honda 73-88 this is the only book i've found that tells how to fix the control system and has good vac diagrams. reccoment that everyone who has a three g get one of these service manuals
There is only one actual vaccume line on the air cleaner,the one that conects to the air door assembly it goes to number eight on the hard lines. if you are going to not have an air door you just cap off number eight hard line. all the other lines on the aircleaner are for supplying clean air to various valves on the engine. they are not vaccume lines! if you block them of you are going to have problems. they use the aircleaner like a big breather. if you don't have an air door you do not need the bleed valve or the check valve on the bottom of the air cleaner. they are conncted together and to the air door motor. once you block off number eight,they don't do anything. the only thing they normally do is control the airdoor motor in the aircleaner. that bleeder in the bottom of the aircleaner is nothing but a thermostat for the airdoor. all the other lines need to connected to the new air box or tube somehow. if you look in the bottom of the original air cleaner,you'll notice that they are just open. they are not supposed to be connected to each other. they feed clean filtered air to other things. the great big plastic tube from the bottom of the aircleaner is really important to have clean air. it goes to the box behind the valve cover. what this box is is a distribution point for clean air to the carb solonoid valves and other things. one end of it has the reed valve attached to it,this is the box with the tube that goes to the exaust manifold. all this does is let pulses of clean air into the exaust,this makes the converter work better. there is a peice that goes between the original aircleaner and this box,it has a wierd piece sticking out the side of it,this is nothing but a tube with a muffler in it.you don't need to use this piece,you can just use normal rubber tube to connect this to the new aircleaner.
got to recomend a chiltons book part #6980 honda 73-88 this is the only book i've found that tells how to fix the control system and has good vac diagrams. reccoment that everyone who has a three g get one of these service manuals