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Thread: Warm Idle Surge

  1. #1

    Default Warm Idle Surge

    Hello. I'm in the beginning stages of tuning the car and have the idle to somewhat where I want it at 900 RPM. I can start it and be idling great in the garage, warms up sitting still, all good. When I take it out for a ride and I'm coming to a stop sign or street light the idle will surge, not die, but catch itself after like four seconds and smooth back out. My question is this something that I need to adjust like IAC setting or something else? Is this gonna get better after letting the system Learn more? I'm watching all the YouTube videos I can with tuning, but not much said on surging idle. With a warm idle I have the IAC to a 2-10% and the Ford Frequency to 315 Hz. I see people using anywhere from 300-400 Hz.

    '93 Fox body, 302 H/C/I with a Novi 1000 SC Anderson B-21 cam. Thanks, Greg

  2. #2
    Join Date
    Aug 2016


    Just finished a remote tuning session with FastManEFI. He was able to fix my RPM dip when coming to a stop, but he could not fix my surge after startup. He said that my Ford IAC was not working correctly. It's a new Ford unit. He said that I need to go with the GM stepper IAC. Apparently tuners do not like the Ford units. I hate to do it, but I'm going to switch to the GM stepper. He tried setting my frequency to 500, but it did not help. He reverted back to my IAC not working correctly. It appears that the Holley system is not fully compatible with the Ford IAC.

  3. #3
    Join Date
    Dec 2009

    Default (Terminator X EFI Software, Better Control Of Ford IAC Motor Behavior) (Terminator X EFI YouTube Tech Video - PWM IAC Control With Advanced 1D Table)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, R134a A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

  4. #4


    Quote Originally Posted by Danny Cabral View Post (Terminator X EFI Software, Better Control Of Ford IAC Motor Behavior) (Terminator X EFI YouTube Tech Video - PWM IAC Control With Advanced 1D Table)
    I've used that technique with one customer and it works pretty well. It does require some fiddling with the throttle blade to get the IAC into a decent range, then tune the Advanced ICF Table from there. Andrew

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