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Thread: Curious Issue Arose

  1. #1

    Default Curious Issue Arose

    To start, I’ve already contacted my tuner and discussed the issue, but I had to go on a business trip for a couple of days and can’t send him the info he needs to even see if this is an EFI issue or not.

    Short synopsis, I’ve had the same Sniper/HyperSpark system in the car for over a year with the custom tune built for the car and it has ran flawlessly since tuned last June. And the system may not be the problem at all. Just curious if anyone else has had anything similar happen to them, and it lead to something EFI related?

    Saturday, after about a 20 mile ride on the interstate, running around 70 MPH and turning around 2600 RPM and temperature at a consistent 190°F, I exited the interstate and got on the highway and the car immediately started making some crackling/popping sounds through the exhaust and hesitating as I tried to accelerate. My destination was only a mile up the road, so I limped it to there and it sat for about 4 hours. When I left, it continued to do the same thing so I went to a gas station about a mile up the road and called my friend to bring a trailer.

    It almost sounded similar to a bent pushrod or a broken spring so I pulled the valve covers and checked the the valvetrain components Sunday and all are fine.

    So after a year of running flawlessly and racking up maybe 4000-5000 miles something happened on this drive. I’ve been around long enough to know it’s impossible to diagnose or pinpoint a problem off of this limited information. Just curious if anyone else has had something similar happen to them and what it may have been? Thanks in advance. Tommy

  2. #2
    Join Date
    Dec 2009
    Location
    Connecticut
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    29,052

    Default

    Originally Posted by Danny Cabral
    Is the Sniper EFI Learning? Is the ignition timing synchronized? Is the fuel pressure 58-60 psi (LINK)? IAC Position
    of about 5% at hot idle? Check for ignition misfires/RPM signal problems, exhaust leak upstream of WBO2 sensor,
    or if the WBO2 sensor (or other sensor) has failed and corrupted the Learn Table. Look at the Data Monitor/Gauges.
    Also, the Holley Sniper EFI will intermittently inhibit Closed Loop at idle, if the AE vs TPS/MAP RoC Blanking values are set too low.
    http://documents.holley.com/techlibrary_199r11259.pdf (Holley Sniper EFI Help Manual)
    http://documents.holley.com/199r11369.pdf (Holley Sniper EFI Troubleshooting Guide)
    https://forums.holley.com/showthread...8356#post88356 (Holley Sniper EFI Fuel Pressure Tester/Gauge)
    May God's grace bless you in the Lord Jesus Christ.
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  3. #3
    Join Date
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    These similar situations happen quite often and you're correct, someone needs to go through the diagnostic process. Based on the information given, I wouldnt be surprised to find a loose injector connector or a blue herring stuck in the throttle body. Point being, the engine needs a complete physical to find the issue.

  4. #4

    Default

    If you've been driving it that long without any issues then you might have forgotten how to take a datalog. All you needed to do was push the button and start a datalog when you felt the car acting funny and then you would have some information that you could use to debug the issue.

    Since the system has been working fine for a long time, we can safely assume that the tune itself is fine so that leaves some sort of mechanical failure. Could be a clogged fuel filter, or a worn out wideband O2 sensor or something else along those lines. Might not have anything to do with the Sniper. Could be something came loose in the engine, a worn timing chain, a lifter failure, etc. Even something as small as a failed PCV valve will have a big effect on how the Sniper works.

  5. #5
    Join Date
    May 2014
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    Bostwick, GA
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    What's the MAP sensor reading, key-on/engine-off?

  6. #6

    Default

    Thanks for the input guys. I was able to get a couple of datalogs when the issue started and have sent them to the tuner for analysis. But I forgot to send him an imported copy of the tune to compare them with the Learn Table, and I had to leave on a business trip for a couple days. I'll shoot that to him ASAP when I get home. Thanks for all of the input and ideas. I planned to do a complete inspection of all electrical and fuel related components when I get back, and you have given me a couple more things to check.

  7. #7

    Default

    @Chuck L: MAP reading key-on/engine-off is 103 kPa.

  8. #8

    Default

    I think I found the problem guys.
    https://youtu.be/SdoC7mtXJM0

  9. #9

    Default

    Quote Originally Posted by rorexjr@aol.com View Post
    I think I found the problem guys.
    https://youtu.be/SdoC7mtXJM0
    Video is private.

  10. #10
    Join Date
    May 2014
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    Bostwick, GA
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    @rorexjr@aol.com: If you want the members to diagnose and make suggestions, why not post your tune & datalog here? This is turning into a 3rd party discussion.

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