So I have a fully built B18A1 block with a built B20 head P8R(not my choice was on motor when I got it). It is turbocharged and tuned on Crome....So I just changed my TB from a BBK to a Sk2 alpha and now I am having issues.....From a cold start the motor will idle high and sometimes will drop but be consistent but when I gets closer to full temp its starts to jump 300-500 rpm. At times it is slow and also when I come to stops when I take it out of gear the idle tends to hang high and then really slowly come down and then start to jump around again. I have replaced the PCV, TPS and set it to .45(was a oriely's special doorman) Tried another IACV from a running car Idk if it had idle issues or not tested the one on the car it and it clicked with 12v put to it....I also covered the hole for the IACV and it did not change anything...Also when I disconnect the IACV it smoothes out ......I have tried setting the idle stop screw higher to keep it up and stabilize it as well as the idle set screw and nothing.....Bleed the coolant completely, Set the idle, Sprayed carb cleaner all around for vacuum leaks found 0, Adjusted the Valves, New fuel filter, ask me and I have probably tried it..............I'm so f*&kin lost.. PLEASE HELP

 

welcome to the world of SK2 TB's. The only thing you can really do at this point is very very small adjustments to the idle stop screw, then readjust TPS. And best bet is to adjust the TPS through crome datalog to 0% closed instead of voltage at the sensor. May also need to alter the idle settings in crome a bit as well

 

I didn't see how the Professional Products, Blox, or Omniman were any better, motoxxxman. They didn't even have a fine idle screw. I thought it was relatively easy, and didn't change the TPS voltage, because, well, the way I took it apart, I didn't have to. I just wrote down the voltage of the TPS before I took it off of the original throttle body to put on the SK2 Alpha. No computers, no muss, no fuss. Same 18 year old Denso OEM TPS sensor I've always had.

 

my personal opinion is that there's an issue with thermal expansion within the sk2 TB's. I've installed plenty of aftermarket and stock TB's, and the sk2 is the only one I've ever had issues with, and it seems pretty consistent too; about 3/4 of the ones I've installed had this same exact problem or some similar form. whereas all other brands, no issues.

reason I mention thermal expansion is because it seems to only work properly at specific temps. if ambient temp is too cold or too hot, or if actual TB temp is too cold or too hot (heatsoak), that's when the issues occur. if the TB maintains temps between 80-125 degrees F, it seems to operate flawlessly.

 

Interesting. Is that with the TB /IACV coolant hoses still hooked up? Because if they weren't I'd completely understand your position wholeheartedly.