So, I just got my motor in, runs great. But... sometimes the idle bounces from 1100 to 1500 (not a big deal, but it makes me antsy when im driving). Its odd for sure, i can come to a stop, wont do it at all. Sometimes it'll do it,then go down to the idle I know the P28 is trying to get to after about 5 bounces. Other times it bounces indefinetly.

I know its related to the P28, because when i put my P2T in the car no bouncy bounce...

I have heard about P28's looking for a FIFV which i don't have. I read this post, and i'm slightly confused by it

https://honda-tech.com/forums/hybrid-engine-swaps-18/surging-idle-fix-chipped-p28-running-obd2-ls-uberdata-907528/

do you guys have any insight?

Oh, btw no CEL's

 

PM sent

 

After my LS VTEC build when I went from a stock P30 ECU to a chipped P28 ECU I had to adjust my idle set screw to get away from a new warm idle surge similar to yours. I went to one full counterclockwise turn on the idle screw to lean out the idle a little bit.

 

My P28 tuned with S100 Hondata has a similar issue but it hunts for idle when cold and only a little 800-1100 rpms. Took it to my tuner whenit happened and he said it was a S100 thing that was pretty common and he had talked to Hondata about it and have sent him updates to fix the issue but nothing really fixes it. Once the AIT sensor sees 120 degrees it stops. Check the idle hunt settings in the tune (no a tuner so cant help there) and check your IAC valve and wiring.

 

IAC valve should work. If not I still have one from my B16 i can slap in there...

Idle Screw sounds like it might do the trick, but i don't want to royally screw something up. Is there much risk messing with that screw? I bet there isn't, but with this being my DD; really don't want to take a chance.