Cold Motor Problem HPT Guys in Here Please
06-30-2007, 09:51 AM
#1
Cold Motor Problem HPT Guys in Here Please Ok My 408 with cam 244 248 @ .05 cold starts ok ,Now here is the problem.I have to wait for it to warm up to about a 120 degrees before I put it in Rev to get out of my garage and when I do put it in rev I have to wait 10 or 15 seconds to find idle otherwise it surges really bad.Is this an IAC Problem?Warm is ok....Thanks
07-01-2007, 09:40 AM
#6
if you're having surging issues and you dont know what RAF is, then you definitely need to tune RAF.
one way to match the airflow is to do a histogram of ECT intervals (just like your RAF table, watch out cuz different years have different resolutions) and use either MAF airflow or Dynamic Airflow as the data for this histo. make sure the units agree, airflow is often in lb/min, and RAF is usually in g/sec.
another method is to use STIT as the data in such a histogram and use that as a modifier to add to the existing RAF table.
we dont really know the algorithms governing idle airflow, so it's all ballpark, but it works pretty well. find out which method works for you and just use that.
one way to match the airflow is to do a histogram of ECT intervals (just like your RAF table, watch out cuz different years have different resolutions) and use either MAF airflow or Dynamic Airflow as the data for this histo. make sure the units agree, airflow is often in lb/min, and RAF is usually in g/sec.
another method is to use STIT as the data in such a histogram and use that as a modifier to add to the existing RAF table.
we dont really know the algorithms governing idle airflow, so it's all ballpark, but it works pretty well. find out which method works for you and just use that.