The AP1 uses pulsed air injection to help cold starts ignite the catalytic converter, the AP2 does not.

But does either car use an exhaust gas recirculation valve?

 

No

 

No S2000 has ever used EGR

 

The air injection system lasted through 2005, starting in 2006 the system was eliminated. So there are two model year AP2s that have it.

 

Thank you, all. This may be the only Honda automotive engine without an EGR, as even the NSX's engine uses an EGR for its entire production run.

Let's segue onto performance and reliability mods now ...

I want to avoid vacuum leaks in an old engine. Let's say I monitor the Manifold Absolute Pressure reading periodically, as part of preventive maintainance. But any of those many tiny vacuum hoses can still leak, and that may be difficult to diagnose.

I recall that, for my own older car, a 2001 Prelude, a bad EGR did not result in a CEL, but it gave a lumpy idle and uneven power from the cylinders at partial throttle.

 

B18C1 and C5 don't have EGR. Neither do D16Z6s. and iirc, most D15 and D16 engines don't. D17s do.

K20 in the Civic Si don't have EGR.

If you monitor MAP voltage, it's also an indicator of tight exhaust valves. On a J V6, if the voltage on a hot engine goes above .9v the valves are getting tight. (all J engines as far as I'm aware have EGR)

 

I'll likely be getting a year 2000 car with a lot of miles on it already.

Do I need to check any specific part of the air injection system? Would the valve that's connected to the exhaust go bad? Or the intake side of the system may have a vacuum leak?

 

EGR and Secondary Air injection are 2 different systems. EGR is for the reduction of NOx, Air injection is for faster Catalyst light off at cold start.

The Secondary Air system used on 00-05 is routinely called EGR, which it is not.

 

Well i think If you observe MAP current, it's also an indication of limited fatigue valves. sydney limo | sydney limo service | sydney limo services | airport limo sydney | sydney airport limo On a J V6, if the current on a hot motor goes above .9v the valves are getting limited. J google as far as I'm conscious with the EGR . . .

 

For my old Prelude's H22A4, will blocking the EGR passage with a bypass plate cause engine damage due to excessively high combustion temperatures?