hope someone can help! i have a 93 touring with: lg. st. port, xst04s, fmic, hks waste gate, apexi (bov, down & mid pipe), holley fp, pettit (ecu, pullies), koyo rad., s-afc, aeromotive fpr, 550cc/1100 (top feed) inj., 5-speed. at this time the lowest idle is 2100 but when in gear the idle will surge between 1700 and 2200 rpm. can anyone help?

 

sound to me like your TPS (throttle position sensor) might need adjustment, or your idle control motor might night be working. Id lean towards the tps though. u do need someone that knows what they are doing though. u need to adjust airbleed screw, tps and the final idle screw.

good luck

rob

 

Well we tried adjusting the idle screw. And it helped a little bit but it will surge if the idle gets down to 1500. I pulled the idle motor reference hose to see if the idle would change but it does not, would this indicate the motor is bad? This car had a Kilo racing motor (single to4x turbo, 1100cc injectors, Pettit racing ECU, etc...) in it, with a pretty big port job on it. Would this cause the surging?

Thanks AL

Please note the Idle was rock steady (1500) before the new injectors and fuel pressure regulator were installed.

 

Sounds like a vacuum leak to me. Check all the vacuum hoses, especially those close to the turbo.