i put a used d17 engine in my friends 03 civic last night and it runs great but the idle surges up and down from 1-2k rpm, i am getting a check engine lightwith codes p0505 and p1505. i swapped another throttle body on to it and no change. i checked for vacuum leaks using carb spray and watching the 02 sensors on a scan tool, and pinched off all the vacuum lines but could not find any leaks. if i unplug the map and set a map sensor code then it settles down but if i clear the code it starts surging again. nothing on the intake side has changed but i cleaned the throttle body while the engine was out because it was carboned up. any ideas?

 

try cleaning out the IACV. I take it you put a new gasket on when you installed the TB? My buddy's had a piece of it sucked in between the idle air port and he throttle opening, causing high idle. But normally the surging is the IAC. Might also want to check your TPS..sometimes if they're not set just right it will cause irratic or surging idle.

 

wat does IACV mean?

 

idle air control valve

 

is it an easy fix because my car does the same thing. except it idles from 1 to 2 and it stops when it feels like it.

 

Yea, just unbolt the iacv and clean the screen and replace the gasket, there is probably a million write ups on how to do it step by step. Google it.

 

thanx dude

 

ok it was the iacv, i took it apart and it was rusted due to the water it ingested when the engine was destroyed, the junkyard one i swapped on was even worse because it sat outside in the rain, completely froze up. the two bad parts threw me off. i had to free up the old one and then it idled right. thanks for the help