Hey guys I got an na rb30, on cold start idles fine once it warms up idles drop to just under 500rpm can not work out why it is doing this! Any help would be much appreciated! Thanks

check your idle on the ecu which has a screw on right hand side of the panel next to the plug which can determine ur idle speed. dont you dare touch your AFM or u will **** it. check the idle air sensor plug on the inlet manifold towards the back is in and next to that plug is an idle screw which u have to play around with and turn. even check your coolant temp sensor their also common to **** things up aswell if you have more questions msg me

Quote: on cold start idles fine once it warms up idles drop to just under 500rpm From memory, on an RB30 the idle speed should be around 700 - 750 RPM, probably would pay to clean up the IAC valve & throttle body then unplug the IAC valve (do this while the engine is warm) then start the engine. If that doesn't fix that,turn the adjustment on the computer with a screwdriver to see whether that changes the idle speed. If that doesn't fix that, adjust the IAA (idle air adjustment) screw on the intake manifold till the RPM reaches 600 - 650 RPM, then plug the IAC valve connector back in and the engine should idle at the specified RPM. I think it would pay to check for things such as exhaust leaks around the exhaust manifold and the operation of the o2 sensor as all of this can affect how the computer controls the idle speed and fuel/air mixture, RB30's tend to be bad for this around the exhaust manifold area (snapped studs and exhaust leaks), the air leaks would cause the o2 sensor to receive a false signal causing a bad idle. Other stuff to keep in check are things such as keeping the fuel and air filters changed once every 40,000 kms and to have a pattern ,flow & volume test done on the fuel injectors to make sure they are delivering the right amount of fuel to the engine. All of that affects idle speed & quality.