Reply to thread

Message: <blockquote data-quote="Addermk2" data-source="post: 818247" data-attributes="member: 8201">that IS wrong, the reason being is that the ECM is programmed to know that at X rpm, with the throttle closed, there should be Y amount of airflow. These f=values can be seen in the TB Airflow scalar, the neutral idle scalar, and the TPS breakpoint.basically, the surging you get, or the hanging idle... is from the car being at a high rpm, the ECM says "the IAC is open to this much, and the throttle is closed.... so then why am I at this high an RPM?" and closes the IAC valve to bring the car down to the PROGRAMMED idle RPM. so now your idle drops off, typically falls below the programmed RPM and the ECM goes "holy shit, im going to stall!" flips the IAC open again, and your RPM shoots back up. thus creating idle surge.NOT setting your base idle to the RPM programmed into the ECM... WILL and i repeat WILL cause rpm hang. Ive seen it and corrected it on more than one vehicle. My own included!As for cam selection causing idle problems in SN-95's... bullshit. My cam is .579/.579 lift 236/245? duration @ .050, and has a 110? LSA. With no tune what so ever in my car... just the basic built in maf transfer function that is already in the eec analyzer software... my car idled smooth as silk at 750rpm. So i say, if you cant get your E-cam, F-cam, shit-cam.. whatever cam, to idle smooth. Its not the hardware... its the person working on it.Keep in mind that there are many factors that affect the way your car idles. Vac leaks, fuel pressure, timing (i still see people running stupid amounts of timing.... its not getting them anything DONT GO PAST 12? FFS!), oxygen sensors, IAC motor cleanliness, EGR function. So if you REALLY cant get your car to idle the way it should... look into these things. I bet you will find one of them ultimately to be the culprit.</blockquote>