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Thread: Pinched yellow wire from coil −.

  1. #1

    Default Pinched yellow wire from coil −.

    Hello. I found the wire pinched after killing the distributor, now IAC is not acting right. It says 0% on screen, but flowing air like it's at 100%. Now the car stalled while driving and display shows no data. I figure this is due to me pinching the wire and hurt something inside the ECU. Any input would be appreciated. Also, when it says no data, fuel pump turn on and stays on doesn't prime and shut off like it should.

  2. #2


    Try resetting the system by disconnecting all battery connections, reconnecting and uploading your latest configuration file. Check for continuity on the yellow wire from coil to plug while the battery is disconnected. If you find no continuity, replace the section of wire that you pinched or use your Ohm meter to isolate where the break-in your wire to be by piercing the wire jacket near the pinch and working towards the plug.

  3. #3

    Default Pinched Wire Update

    I disconnected battery to reset everything. Also moved all spark plug wires away from Sniper wires. Engine started and AFR showed fine while cranking, then went to 32 AFR while tuning and eventually stalled. I talked to Holley support and they said display showing No data means ECU is fine, but shutting down because it has RFI. I have never had any RFI issues prior to pinching wire. I've since repaired the pinched wire. I used a heat shrink butt connector. I do have one kinda dumb question. My distributor I installed has a crack in the coil cover. I didn't think this could cause any issues, it's only plastic cover. I now wonder if it's radiating RFI through that crack? I'll try another cover on it tomorrow and see what happens. Holley said pinching the yellow wire should cause no damage to the ECU. I really hope they're right. The WBO2 sensor wire is routed underneath distributor, I'll try to reroute it off to the right side tomorrow. Where are the common RFI areas to be aware of? Does HEI coil emit RFI? I know spark plug leads and have also heard alternator can as well. Is there any other RFI sources i should be careful of? Car has manual fan.

  4. #4
    Join Date
    Dec 2009


    Quote Originally Posted by Chris805 View Post
    My distributor I installed has a crack in the coil cover. I didn't think this could cause any issues, it's only plastic cover. I now wonder if it's radiating RFI through that crack?
    Yes, the ignition has to be a sealed system (component-wise).
    May God's grace bless you in the Lord Jesus Christ.
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  5. #5


    The one thing I haven't changed is the little resistor inside the distributor. I changed the whole distributor so the new one has a digital type resistor instead of a capacitor type resistor. I also changed the coil cover I changed the entire cap & rotor moved WBO2 sensor cable aside. IAC still not seeming to follow commands. It will show 0 on display and still flow air at idle. The biggest issue I'm currently fighting is the WBO2 sensor seems to be dropping out. It will show fine while cranking the work OK once warm the idle will start cycling following the WBO2 sensor the sensor will be fine and then all of a sudden spike to 19 on the gauges, but over 32 on digital display. I disabled Closed Loop and held a steady RPM and engine sounds great or seems like the WBO2 sensor is showing a false lean forcing the sniper pig rich and it tries to stall itself. I looked at the wave forms of RPM, IAC, AFR, etc., looking for any signs of RFI and I couldn't find any. I believe I have something going wrong inside my ECU. Tomorrow at work I will hook up a new Sniper to my car and see what happens. I never had any RFI problems before pinching the yellow wire. Since I repaired the wire I have been fighting a slew of issues. Could the resistor capacitor thing in distributor be causing RFI even if it was brand new? I can try swapping in my old one to see if it makes a difference. Just getting a bit frustrated feel like I've been battling these problems all week long.

  6. Default

    If your running a points style distributor, the item inside is a capacitor and is wired across the points to suppress arching on the point contacts when they open. Suggest performing a forum search looking for EMI, RFI, Noise, etc. to find other troublesome source locations to look at. There have also been a few WBO2 and IAC threads that may help. Multiple posts exist discussing the topic and how to resolve. Also how to track down the source (E.G. with an AM radio).
    When reviewing your datalogs, right click on the graph and select 'Mark Data Points'. Zoom in and look for missing data points. Look for negative times and trended data going backwards in time rather then increasing through time. And have a read of:
    1970 XW Fairmont (presented as a GT Falcon Replica), 351 Cleveland with Aussie 302 2V closed chamber heads. Edelbrock F351 2V dual plane intake manifold. Camtech CT21544 (234/238@050", 570/579lift, 2600-6200rpm quoted range, 110lobes) 1.73:1 roller rockers. AOD Transmission. Ford 9" 3.5 Diff ratio. Pacemaker #PH4050 2v Tri-Y extractors to 2.5" Hi Flow V-Tex merge pipe with dual 2.5" exhaust through Hooker Aero Chamber Mufflers. Holley Sniper EFI 4150 Super Sniper 650 with HyperSpark Ignition.

  7. #7


    UPDATE: I really do love this forum, all of your suggestions are great. I replaced cap & rotor rerouted pink & yellow wires away from plug wires, as well as Sniper main harness and WBO2 sensor. Car runs great and acts normal as far as displays go. I did have to change my WBO2 sensor. I recent took my AFR 195 heads off and installed the Brodix Dragon Slayer and had issues burning oil. Turned out Brodix heads came with seals only on the intake valves. I drove two weeks then installed the valve seals on the exhaust. I'm assuming the two weeks of burning oil prematurely killed the WBO2 sensor. Installed new WBO2 sensor and AFR no longer spikes. I'm running a factory for 1978 HEI distributor. Thanks everyone for all the input.

  8. #8
    Join Date
    Jan 2010
    Brisbane, Australia


    Quote Originally Posted by Chris805 View Post
    The one thing I haven't changed is the little resistor inside the distributor. I changed the whole distributor so the new one has a digital type resistor instead of a capacitor type resistor.
    You need to read about ignition system design. Or can you post some pictures of these parts please? Gary
    Regards, Gary

  9. #9


    The capacitor is for radio noise, I believe it's to filter out the AC current. I've never really understood how to post pics on here. If you take cap off HEI, then take rotor off, you'll see module looks kinda like a boomerang. One side plugs into wires which go to the pickup coil in center, other side has the resistor/capacitor (condenser) not sure what the correct term would be.

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