Idle tuning
So I’ve had a high idle for sometime and have changed the idle settings in the Xcal, set the TPS, and manually adjusted the Accufab single blade a few times over the years and have only achieved a drop from 1,250 to right around 1,000 (970 to 1130ish on the data log).
It’s spring time which means it’s that time of the year I don’t mind messing around with it a bit before I get burned out even thinking about working on the car. So I spent the last hour or so starting fresh with adjustments. First I warmed her up with a drive, then set idle in park and neutral settings to 690 & 694, then I removed the IAC but left it plugged in and duct taped the inlet/outlet shut and manually adjusted the single blade easily down to around 700 or so. Then I reset the TPS to as close to .98 as possible (ended up at .95), re installed the IAC and let her run for 10 minutes to relearn.
Zero change. I tried two other known to be good IACs with same results, even swapped in a new gasket. So I started data logging RPMs and never noticed before RPMs demanded and I see the demanded is locked in at 992 even though I set it to 690?? That makes sense as my idle bounces between 970 and 1030 give or take. She’s always had a small bit of a choppy idle, nothing new there.
So am I fighting a lost cause? If I can’t reduce the demanded idle down (even though I have in settings) then the IAC will always be bouncing to achieve that 992 RPM. I never caught this PID in data logging before and I wanted to make sure I’ve done everything on my end and I’m not missing something here before I bother Marty and Jeff.
I’m ultimately trying to cure a bad part throttle bucking trying to maintain speed in and out of pedal at anything under 35/40 in any gear then every gremlin has been fixed. It takes a seriously steady right foot to acquire any form of smooth and a left foot on standby to quickly clutch it to smooth it out. Seriously annoying in traffic or even in my subdivision.
But hey, I did get my constant running fan fixed this year! That’s 1 of my only 3 complaints. That fix was 33% of my struggles!
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SOLD 12/31/2021
Cobra short block / ProCharger F1-A / Cog drive upgrade / Manley valves / Brian Tooley Racing valve springs / 80# inj. / -8 fuel line / -6 return / Aeromotive 340 pumps and regulator / 2012 GT500 TR6060 six speed / twin disc clutch / Driveshaft Shop GT500 upgraded CV joint shaft / BA5000 blow thru MAF/ 4.10's / Ford Racing 31 spline set up and Girdle / Metco D.S. safety loop / Stainless Works headers, cats, and everything else out back / ClassGlass hood / Bob's hood strut mod / Hurst line lock / Metco control arms / Addco front and rear sway bars / Monroe severe duty shocks all around / Race concepts rotors / Badgeless grille / 35% tint / FBM's interior LED kit and ambient lighting kit / Pioneer FB700 deck / kenwood speaker 4 Ch. / Rockford Fosgate 10" sub and amp / Kicker 6 X 8's all around / back up cam / bluetooth / Pioneer Xm / 704 RWHP 603 RWTQ tuned by Mo's Speedshop.