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Thread: IAC Erratic

  1. #1

    Default IAC Erratic

    OK guys, my IAC is acting erratic. Holley is looking over my datalog, but I just wanted to post it here for you guys to look at also (never hurts to have more then one mind). I've tried to do the IAC reset with the tape over the IAC and seemed to work, but the problem is after it runs for say about 45 minutes it starts to go crazy. I turned the car off and hit datalog and restarted the car and as you can see it was running great then the IAC went crazy. It could be RFI, but that's were I need your help. I'm new to the Sniper and how to look over the data, so any help would be great. Now here's what I've done to try and look for RFI. Moved wires as much as I can apart. All vacuum ports are closed off, nothing hooked to Sniper. Wires are 7mm suppression, but I'd change if need be. Spark plugs new ACDelco and gaped to factory specs, and boot grease on ends. The coil is not a new part so may change it too, but it's the closest thing to the back of the IAC (stock location). This is a non-timing control on a 327ci. The alternator is new and a 3-wire so no voltage regulator is being used and the wiring runs to the driver fenders and taped. If you guys can think of anything I left out, just ask.
    Attached Files Attached Files

  2. #2
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    26,999

    Default

    Ensure the fuel injectors or spark plug wires (or any other high voltage wiring) aren't too close to the IAC motor/wiring.
    The IAC motor is easily susceptible to electrical interference, and it'll cause strange occurrences and become inoperable.
    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, 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.

  3. #3

    Default

    Thanks Danny. Here are some pictures of my setup. Coil is the closest to the IAC motor. Plug wire are in stock location under stock manifolds. Do you think that the stock location of the coil is upsetting the IAC. How about my datalog did it look like RFI?
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  4. #4

    Default

    Yes, you're showing signs of EMI. When left in the datalog screen, you should see a consistent 60 (give or take a few) bites per second. When you switch between screens you'll see a significant drop in information per second. If you leave it on some other screen, such as the Gauge Panel, you will get a consistent 16 (give or take a few) bites per second. When you see large and inconsistent gaps in information, that's a sure sign of EMI. I'd suspect the distributor, due to being a magnetic pickup. Coil is likely also due to the heat soak concern. Could be as simple as cap & rotor. How's the wiring for the Sniper? Wait a minute, do I see the CAN Bus connector laying on or near the coil and distributor? If it is, that will surely cause it.
    Last edited by a b c; 10-22-2020 at 07:14 PM.

  5. #5

    Default

    Quote Originally Posted by a b c View Post
    Wait a minute, do I see the CAN Bus connector laying on or near the coil and distributor? If it is, that will surely cause it.
    Yes, that's the CAN Bus connector laying there. It was on top of the air cleaner when running I moved it when taking the picture, but I'll move it more out of the way. I had to keep moving it to adjust the IAC during the reset. I'll get another cap & rotor to be on the safe side. Thank you for the information. If all else fails, would I need to fab a aluminum shield to go between the distributor and Sniper? (I'd hope not to use one.)

  6. #6

    Default

    OK guys. I moved some wires around and today the '63 Impala 4-speed ran great. I took another datalog to let you guys see if it looks better then the first one I posted. Plus anything you can help me spot to lean on this thing the better. Advice always welcome. This is just a datalog of me pulling out in first gear letting the Sniper learn. Pretty sure I'm going to have to do the progressive throttle linkage because the throttle is stiff.
    Attached Files Attached Files

  7. #7

    Default

    Transfer Learning To Base, and then start driving it around the block to see how it works.

  8. #8

    Default

    How do you transfer it? I just learned how to open the datalog.
    EDIT: OK, seen a video I think I need to download the GCF File.
    Last edited by Watkins Restorations; 10-27-2020 at 10:23 PM.

  9. #9

    Default

    If you have a laptop hooked up to the Sniper you do it live. If you're working on a desktop computer, then you download the tune to the SD card, open it in the computer and make the adjustment, then upload the tune back to the Sniper.

  10. #10
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    26,999

    Default

    This is outlined in the Sniper EFI instruction manual.
    http://documents.holley.com/199r11031r.pdf (Holley Sniper EFI Retrieve, Save & Upload GCF - SD Card & Laptop/PC Usage, Pages 72 & 73)
    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, 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.

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