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Thread: Problems after cleaning up wires.

  1. #1

    Default Problems after cleaning up wires.

    Well kinda a funny story. I know there’s a big discussion about making sure wires are tucked away nicely to keep from any problems. Well my Sniper had been hooked up for maybe 6 months or so, never tucked wires away just had them kinda bundled up under hood with zero problems, ran great the whole time. So last week I decided to cleanup wires and go through firewall to tuck and run them all to look real nice. Now the problem starts. WBO2 sensor reading fluctuates more than it used to and when I get on the throttle, it jumps up & pegs into red, and when I let off it drops down to the 9s, then few seconds later it’ll go back to fluctuating around 12-14. So now I’m going to bundle all wires back up, not really. I’m sure it’s just some interference somewhere. I’m going to look into it today to try & narrow it down. Just thought it was kinda weird that it ran perfect before, and all I did was reroute wires through firewall to make it look cleaner. I’ll update when I figure out what’s going on.

  2. #2


    The firewall does a good job shielding EMI. Perhaps you routed the wired too close to either the coil, distributor or an ignition box? Datalog will show if you have any parameters out of whack.

  3. #3


    The wires are no closer to anything than they were before. May have one of the ignition box wires too close to the EFI wires, that’s what I’ll double check hopefully today. Thanks for the advice. Is there a certain wire on the EFI system that will cause the EMI interference?

  4. #4


    You don't say if the engine runs any worse? As my engine tuned, I'd see variations in AFR all the time with spikes up during acceleration and down with deceleration. Are you sure the handheld wasn't getting interference before, so did not display everything? Now it has a clean signal and everything shows up.

  5. #5


    It ran better before. Now it has a bog. I punched it yesterday and went through the gears it said three speed automatic and then it just died out. I had to turn ignition off and start it again it had never done that before. The only reason I messed with anything was trying to clean up under the hood, should’ve left well enough alone, I guess. Now when I let off the gas and the air/fuel fluctuates, it idles down low like it’s going to die.

  6. #6
    Join Date
    Jan 2010
    Brisbane, Australia


    Quote Originally Posted by Gen2Van View Post
    The firewall does a good job shielding EMI. Perhaps you routed the wired too close to either the coil, distributor or an ignition box? Datalog will show if you have any parameters out of whack.
    He has moved the bulk of the harness BEHIND the firewall, so unlikely to be EMI now, it could've been before, especially with a quick sloppy installation like some. Sounds more like the WBO2 sensor wiring is wrong since it goes lean on acceleration, and rich on deceleration (into the 9s). Gary
    Last edited by Gaz64; 02-27-2019 at 11:20 PM.
    Regards, Gary

  7. #7


    I've needed to reseat the WBO2 plug before. Make sure the plug is clean and tight, worth a shot.

  8. #8


    That’s what I’m saying. It ran better before with my “quick sloppy wiring”. I don’t see how I could’ve had EMI issues before when it ran really good. It may be WBO2 sensor, but kinda wired it would’ve started giving problems only after I cleaned up wires.

    I’ll give that a shot Brian.

    I just did a datalog. I’ll try posting it up later today.

  9. #9


    How do I upload a datalog?

  10. #10
    Join Date
    Dec 2009


    Originally Posted by Danny Cabral
    For further assistance, post your Config File and a short datalog of this occurrence for us to analyze.
    Also, review the datalog and inform us of exactly where in the datalog (time/seconds) the problem occurs.
    Datalog & Global Files can be linked to a document hosting website. I use
    Files can also be "zipped" (compressed zipped folder) & attached directly to a forum post ("Go Advanced" & "Attachments").
    Your Config File is in the "Documents", "Holley" folder, "Sniper" folder, "Config Files" folder (.hefi file).
    Your Datalogs are in the "Documents", "Holley" folder, "Sniper" folder, "Data Log" folder (.dl file).
    Someone will analyze/troubleshoot the problem & offer advice. (How To Record & Email A Datalog)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 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, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, 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 & MT 245/45R17 tires.

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