Hi Guys,

Local Honda garage seem to have FINALLY done what I've been requesting for months and investigated all sensor readings that might be causing the misfire

After 'resetting everything' the car is fine right up to the point when the Air Pump kicks in - then it all goes shitty again

So, what does the Air Pump do and does this give anyone any clues about why it's misfiring?

As far as I'm aware the car hasn't recorded an error code specific to the pump - just a cylinder misfire.

Cheers,

J

 

The air pump only works after an engine start. If the engine is already hot, it may not work at all. If it's warm, perhaps only for a few seconds and if the engine is stone cold, it can run for a couple of minutes or more. The pump pushes air into the exhaust manifold to assist the catalytic converter in resolving much of the unburnt hydrocarbons, which is most prevalent after a cold start.
I suppose your primary O2 sensor could see the extra air as a need to adjust the a/f in a way that could subsequently produce a random misfire. This may not necessarily mean you have a misfire, but it could mean you have a bad sensor somewhere in the system or a bad ECU that can't interpret what it sees.

 

The air pump does draw a huge amount of current (60 amps at start up) check the battery and charging system. Low system voltage can cause any number of strange engine
performance issues.