Hondata

My posts are getting quite regular as I try and get my k20a2 working in my kit car....

I am having a problem, which is much as is stated in the title:

When I start my engine, it runs initially seemingly fine, though the revs are quite high - around 2.5k. After the engine gets a bit of heat in it, the revs pick up slightly, to just under 3k, then start surging. From the exhaust I initially concluded it was the injectors cutting, and have now datalogged the event to check the situation.

The engine is a stock k20a2, with a different (much shorter - for mid engine installation) exhaust, and a cone filter on the intake. The map is the factory european type-r map.

I have attached a datalog file, and hope that someone can shed some light on this for me.

I almost forgot.... if i raise the revs using the throttle, the engine runs smoothly and doesn't cut the injectors.

Thanks in advance.

John.

Since posting I think I've worked out why this is happening...

Does this sound logical?

I have a vacuum leak, causing the revs to rise, when they get to a certain point the ECU cuts the fuel as it thinks (from the throttle position and revs) that the engine is in over-run. The engine then reaches the lower limit of the injector over-run cut, then turns them back on.... revs rise... loop starts over?

Yes, fix the vaccum leak first. You should also clean the idle valve. Finally, if the main relay is not wired as per the stock wiring diagram, the ECU does not get battery backup voltage, and the idle learn procedure is never performed.

Thanks for the reply. It transpired my idle valve spindle was locked solid!