Air injection system

[Fuoss484]

Have a 2003 Acura NSX. Was wondering what the air injection system does? Is this system able to be removed without causing any problems to the car, running the oem ecu? I am not concerned with emissions.

Reason I ask. Bought a NA2 intake manifold that does not have the holes for mounting the air injection system, and was going to use it on my 2003 NSX.

 

[jwmelvin]

It warms up the cats more quickly. The ecu will throw a code if it's not there.

 

[jwmelvin]

But maybe you could fake it. I think the code relates to the motor not running rather than the air not being injected.

 

[docjohn]

My 96 obd2 ecu does not throw a code with a 2000 motor and the piping for that system was removed.holes plugged.hth

 

[Fuoss484]

The holes that are plugged on the intake manifold or the hoses from the air pump?

 

[docjohn]

I think the manifold

 

[jwmelvin]

That makes sense because the ecu does not expect the signal from the current sensor. With a 2000+ ecu, it will expect that signal.

The air is drawn from before the throttle plate and pumped into the intake after the plate. You may see it in the 2000 Supplement at 11-73.

 

[docjohn]

yes makes sense.......having a 96 ecu is like having type AB blood:wink:

 

[Old Guy]

The air is drawn from before the throttle plate and pumped into the intake after the plate. You may see it in the 2000 Supplement at 11-73.

The air from the air pump is injected into the exhaust manifold just downstream of the exhaust valves. I expect that the free oxygen in the air and the CO in the exhaust gas combust releasing more heat which helps to light off the catalyst. The port that is located after the throttle plate provides low pressure to operate the air control valve on the discharge of the pump.

If the OP wants to use the earlier manifold, he could probably just leave the air pump connected up electrically (edit - after plugging up or disconnecting the ports). Since the ECU monitors pump current it may be happy and not generate any codes even though its not doing anything. Of course, it probably wouldn't be too hard to add the ports into the intake manifold for the control valve and the pump intake.

 

[jwmelvin]

Ack! Indeed and I apologize for that misinformation. The diagram does show the air going into the exhaust after the cylinders where it reacts with exhaust gas to raise the temperature. Must be unburned hydrocarbons that react I would think.

 

[Old Guy]

Must be unburned hydrocarbons that react I would think.

Could be the HCs completing some combustion; however, most of that probably occurs on the catalyst surface. CO is a highly combustible gas (CO and hydrogen is usually the gas that is produced in coal gasification systems) and would probably be the more likely candidate to complete rapid combustion for the purpose of heating up the catalyst. This is probably a somewhat academic point.

To the original poster, other than the weight associated with the additional hardware, the air injection system does not result in any reduction in engine performance. In fact, I seem to recall that by assuring that the catalyst lights off quickly, it might help to extend the useful life of the catalytic converters. Somebody who is more knowledgeable about catalysts might be able to confirm or refute that last point.

 

[jwmelvin]

CO is a highly combustible gas (CO and hydrogen is usually the gas that is produced in coal gasification systems) and would probably be the more likely candidate to complete rapid combustion for the purpose of heating up the catalyst.

Neat, thanks for the info!