crappy idle problem

[19civicdx92]

ok heres the deal. I bought a civic dx with a d15b engine swap. The only problem is it idles really high, probably about 1700 rpms for a couple of minutes, then it pulsates up and down till it warms up then its fine. Anybody have any suggestions? Also there is a round gray connector toward the back of the engine that is not hooked up, looks like the one that goes to the IACV and stuff. Any idea on where it might go? Looked everywhere but can't find any sensors that don't have any connectors on them. Any help would be great. Thanks

[94civicEX]

My friends swapped hatch had that same problem, we had someone tell us that it was a failed IACV, he fixed it somehow, but I'm not sure how he did....

[CivicSiRacer]

Idle control valve.

[Import-Tooner]

also check your coolant levels. That can make it pulsate up and down. There is a air screw on the throttle body that you can mess with but I wouldn't change it too much.

[94civicEX]

Originally posted by import-tooner
also check your coolant levels. That can make it pulsate up and down. There is a air screw on the throttle body that you can mess with but I wouldn't change it too much.

Did Andrew not tell you how he fixed yours?

[Redcivic]

I had the same problem when I put a D15B in my cousins Dx Coupe. I could never figure it out so she just learned to live with it. That little motor rips though. let me know if you find out WTF is wrong.

[19civicdx92]

hey guys thanks for all the help. I figured out the problem. Ok when the guy swapped out the engine he put in the ecu that came with it and never hooked up the vtec so my check engine light was on. I decided to check the codes anyway to see what came up, 21 which I knew because of vtec and also a 19 which is a lock up selinoid, WTF??? mines a manual so I put in the old ecu that it had in it and boom ran perfect. SO I think I will just rechip my old one with an aftermarket chip and run a vtec controller to take care of the problem. Thanks for all the help.