Okay i'm stuck.

I just put in some new itr piston (nippon) and a set of dual valve spring titnium retainers with some flat valves in my gs-r(b18c1) and now my car idles weird. it drives fine but when you come to a stop the idle goes down to 500 then jumps to 1100 then to 1200 then back to 1100 then back to 1200..... the idle is from 1100-1200 back and forth when your on a stop. I never had this problem before either so i dont think its my iacv or fast idle valves. Does anyone know what could be wrong?

 

Well lets see, you jacked up the compression ratio without compensating with any extra fuel, and you expected it to act the exact same?

 

thanks for the reply you sound like you know something. What should i do now? help please

 

bump... any suggestions

 

You need to get your car dyno tuned.

 

Engine management, and a tune. I hope you're at least running premium fuel...

Upping the compression means your engine is more likely to detonate, or prematurely ignite before the spark plug fires. This can do damage to an engine, even destroy it if it repeatedly happens. You need some sort of engine management system so that a tuner can compensate for the fact that you just raised your compression with no other changes. Honestly, you probably shouldn't drive the car until you get that taken care of.

I don't mean to be rude, but did you even research what ITR pistons do before you installed them? It's really important that you do some research and understand what the effect of raising the compression ration is, and why it can be dangerous for your engine if not tuned properly.