Rough Idle w/ 60mm T/B

[SoCalS14]

OK fellas, I was able to pick up a 60mm throttle body pretty cheap off ebay. I cleaned it and installed it today (on a S14 SR, S15 turbo, FMIC, Walboro pump, stock injectors/ECU). Now the car runs fine, rev's good, and overall, I feel a bit more throttle response...BUT...

I noticed that my car idles a tad rough now...still idles around 700rpm, but noticably rougher...Almost seems like its missing...but I know its not...It was fine before the swap...

Would this have anything to do with the throttle position sensor? Can I adjust it? Or does it have to do with the larger throttle body, i.e. this is something to expect?

Any suggestions or reassurance would be helpful.

[Nismo_Freak]

Yeah slight variance in idle TPS settings could change a few parameters to cause irratic idle. I'd calibrate it using a multimeter.

Calibration is in the FSM.

[robbbby]

If you're going to try adjusting your idle you can follow these steps

1.) Warm Car up to Highway Driving Temp2.) Turn off Car3.) Lower Throttlebody IDLE screw to minimum (Do not Bottom Out)4.) Disconnect TPS5.) Start Car6.) Observe IDLE RPMS7.) Turn off Car8.) Raise/Lower IACV depending on level9.) Repeat steps 4-7 until IACV set to 850 +/- 50rpm10.) Plug in TPS11.) Start Car12.) Adjust TPS to .455v using a voltmeter on the middle pin

[SoCalS14]

Thanks guys, I will give it a go tomorrow!

[s13sr20chris]

also note that the ecm will "learn" your base tps voltage and try to adjust for that. meaning that the idle will get better on its own if the tps is the only fault. i still reccomend adjusting it right though.

[SoCalS14]

OK I followed Robby's suggestions, and the idle is improved...However, I think I screwed up...Its still not as smooth as before...Why is it important to adjust the IACV when the car is off???