i have a P28 USDM B16A3 ECU and i just dropped a JDM OBD1 B16A into my car, after running the car for a while, the car will idle from stock point to 1.5k about 10 times up and down and then settle back down and idle fine.

Is this something in the sensors maybe or did a vacuum line come loose?

 

The surging isprobably the Fast idle thermo valve located underneath the throttle body. Its probably clogged up and needs to be cleaned, its a pretty common thing to happen to Honda's when they have higher mileage and are still warming up. i seriously doubt its your ecu.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LostSolVTEC &raquo;</TD></TR><TR><TD CLASS="quote">i have a P28 USDM B16A3 ECU</TD></TR></TABLE>

A B16a3 would be a P30, not a P28. A P28 is from 92-95 ex/si.

You have any CELs (Check Engine Light)?

 

friend of mine told me it was a P28...oh well, no CEL's but it does this while the engine is warm so i don't think it's the fast idle, i'll check it out though. When they did the swap, my dad said they had the car runnin for over 2 hours and it never did this once, just when i got it back and started drivingit

 

try cleaning the EAICV on the back of the intake mani

 

thanks i'm gonna double check all the connections as soon as the engine cools down