I have read the FAQS. on the IAC diagnosis but it is not as clear on the Rex Regina IAC. First thing noticed was that I can`t slowly increase the engine speed because it jumps to around 1200 rpms. Occasionally the idle was
hunting slightly. The IAC was changed out for another unknown used one with no results. The old one was cleaned with regular carb spray and the other was cleaned with the CRC brand that was plastic friendly throttle body cleaner. Now the idle hunts from 750 rpms to around 1200 rpms. After engine is at operating temp. it idles at around 850 rpms. When I rev the engine to around 1500 rpms the engine idle stays there. TPS was changed with a known good one and throttle body was cleaned. All grounds are clean and tight. On trying to adjust the idle screw I found that the idle would
not fall below 750 rpms even with the set screw backed off completly and the inlet hose to the IAC crimped also the linkage was disconnected. The TPS is adjusted so as to hear the click just off idle. The codes were cleared with each adjustment. Before I spend over $300.00 bucks for a new IAC I would like to be sure.
Question, Does the IAC open and close slowly while in operation by recieving less than battery voltage via the computer? Should I check voltage at the computer for a signal from the TPS and IAC, If so which pins keeping in mind it is the Bendix Rex Regina system. The IAC only has too pins, ground and 12 volts.
The pins are marked + and -. I did apply 12 volts to check for opperation and hope that I didn`t damage them.
Also checked for vaccum leaks. Thanks for any help! Larry