Ok, I'm relatively new to civics, but a pretty decent mechanic. I asked around and ended up picking up a JDM D15b from a 96-00 civic (w/obd2) to put in place of my very dead D16y8...

The guy I bought it from told me to use the D16y8 intake and the rest is a straight swap. So I did (used the TB, intake, fuel rail from the D16y8). B/C the harnass I had is the one from my old D16y8, I swapped out the double vtec solenoids for my single.

Right now, honestly I don't care even if I get vtec running until I solve my bigger problem - the idling. It runs great and idles fine when it first starts (1400 cold), but as soon as it heats up I get surges - 2200 rpm, then drops to 1000, and back up. I can't seem to find a real answer as to what's causing this... .ANYONE??

 

bump for more help! I'm f**king stumped here!

 

I'm assuming it's probably a vacuum leak or vacuum hose unplugged. I had that problem for the longest. That or perhaps a dirty IACV.
Do me a favor and take a picture of that dual solenoid? I just picked one up but wanna make sure it's the right one for my D15B. I'm going to be setting the VTEC-E to kick on with an Apexi VAFC2

 

it's the FITV, there's a really good write up on how to fix it on this forum.

https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/how-fix-your-idleing-woes-fitv-iacv-2153910/ From the EF section but parts are almost identical.