gmrulz4u Posted July 19, 2003 Report Share Posted July 19, 2003 When idling, what is a "normal" amount of RPM fluctuation? Because I am able to see, using a scanner, that mine fluctuates rapidly, up to about +/- 50 RPM's. I can also see the ECM's "desired" RPM's. Here's an example: Desired Idle: 700 RPMs Actual Idle: 680, 712, 695, 723, 673, 689, 709 etc...(changing rapidly) So, I don't THINK it's a problem, but I just don't know if an engine going up and down every second, sometimes by 50 RPM's, is completely "normal" or not? Also, what's your guys TAKE on this: One of my Scanner's parameters is "IAC Motor Reset". The manual only says the following with regards to it: An indication of whether the Idle Air Control motor has been returned to a calibrated position if it has lost its reference count. The only two readings possible are YES or NO. Mine has ALWAYS said "YES". So, does this mean YES the IAC has been returned to a calibrated position because my ECM has lost its reference?? Or, does it mean the opposite? In other words, I can tell if this is a GOOD thing or a BAD thing? My stupid manual says what the NORMAL reading is for ALL other parameters EXCEPT this one, just my luck!! Anyone take a stab at any of this?? THANKS! Quote Link to comment Share on other sites More sharing options...
Brian P Posted July 19, 2003 Report Share Posted July 19, 2003 NORMAL Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted July 19, 2003 Report Share Posted July 19, 2003 RPM fluctuation is normal and I think that the "YES" is saying that it has been re-calibrated Robby Quote Link to comment Share on other sites More sharing options...
gmrulz4u Posted July 21, 2003 Author Report Share Posted July 21, 2003 So RPM fluctuation is normal, but HOW MUCH is not normal? I assume that an engine going up and down by 200 RPM's while idling is NOT normal...so what amount is acceptable? Quote Link to comment Share on other sites More sharing options...
Whiskey River Posted July 21, 2003 Report Share Posted July 21, 2003 From the readings you posted, it is within the +/- 50 revs of the desired idle. When it gets above or below the 50 revs, then you may have a problem. Otherwise, unless it is causing some vibrations, don't worry about it. Quote Link to comment Share on other sites More sharing options...
gmrulz4u Posted July 21, 2003 Author Report Share Posted July 21, 2003 Oh OK, thanks! Quote Link to comment Share on other sites More sharing options...
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