Stock D16 engine, P28 w spoon chip.

I wanted to revert the ecu to stock so per instructions on here I simply cut the J1 jumper.

Now the car idles @ 1100 and when the foot brake is aplied the idle jumps up and down to 1600 rpms. Once I release the brake it settles back down after a few seconds.

Other than that the car performs as stock. No check engine lights.

Any suggestions on what could be wrong?

 

engine is a stock D16??
the P28 is designed for the stock Z6, any other engine or other changes to the engine will result in lesss than desirable results.

BTW, everytime I hear "spoon chip" my brain twitches.
Unless you purchased the ECU from spoon directly (and they had your car to tune it) it's not a spoon chip. It's likely a super crappy set of maps that runs way too much fuel.

 

Ok. Thanks for replying.

It is a z6 engine.

also the chip has spoons label on it, so I am to assume it has a spoon chip.

Regardless of the tune the J1 jumper is cut so my issue is happening on stock tune.

 

this will sound odd, but which P28 is it?
if it really is a spoon chip, then it's highly possible that the P28 you have doesn't have MCU code in it. (stock maps in the ECU)
reason - spoon and mugen received special ECUs from honda to make into their race ECUs, so no stock maps were needed.

what are the numbers on the tag 37820-P28-???
also the three digit number on the MCU, the large black chip above the spoon chip.