So i have a 93 civic Dx with a jdm b16 (vtec is wired in correctly with a p28 ecu)
and all the sudden since its been cold out it has been idle surging when the car is cold
I dont have any water in my radiator (its all coolant).
I believe i do not have a vac leak, what could this be, since it only has been happening since its been cold out (below 30 degrees)
thanks guys

 

idle air control valve on my last 2 hondas took a crap as soon as it got cold but my other response was gonna be do you have coolant if your low it will do it.... direct fill you radiator and see if it helps if not iacv is my guess

 

subscribed. lately I have had the same issue (once it got cold here too) but it's only when it is between right after warming up and running for 10 minutes plus (that 7 minute gap)...if that makes sense. I might just try a new iacv mine looks brand new and i have cleaned it twice but i can't imagine what else it could be. I have tried adjusting the idle multiple times. I'll check my rad too....please post your results op i am interested to see if you can solve it.

 

radiator is full
so you think its prolly the IACV?
or could it maybe be the fast idle valve?

 

search for the trick to test the fitv etc....you take you intake off and see which holes get vacuum in you tb