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Holley Sniper EFI

How-To Videos

Frequently Asked Questions

  • Question
    Can the Sniper be used with a dual plane manifold?
    Answer
    Yes. While a single plan manifold can have better distribution for a throttle body application, The Sniper is fully capable of being utilized on a dual plane manifold.
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  • Question
    I have a true dual exhaust. Will the Sniper be okay using a single O2 sensor?
    Answer
    Yes. A properly functioning engine should not show a great variance between banks. If you choose, you can install an O2 bung in both banks to validate engine health and install the O2 sensor in the bank that reads slightly leaner.
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  • Question
    Is the Sniper approved for use in marine applications?
    Answer
    Yes, Holley does have Sniper EFI Marine certified applications.
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  • Question
    What type of camshaft can I use?
    Answer
    The Sniper has pre-programmed base calibrations that are a good starting point for most street drivable camshafts. The setup wizard offers three cam choices for Stock / Mild ( 14+ In/HG vacuum ), Street / Strip ( 8-13 In/HG vacuum ), and Race ( 7 or less In/HG vacuum ) More aggressive camshaft grinds will likely require laptop tuning with the aid of the Sniper Software in general engines producing more than seven in/Hg Mercury at idle are acceptable.
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  • Question
    Once the Sniper is programmed, can I unhook the handheld?
    Answer
    Yes. You can simply use the handheld for a tuning device and then unplug.
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  • Question
    Can I use a Vacuum advance with the Sniper?
    Answer
    Yes, the sniper has a timed spark vacuum port that will operate the vacuum advance.
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  • Question
    Is it required to have timing control when using the Sniper
    Answer
    It is not required to utilize the Sniper’s timing control feature but it will add several benefits. We actually recommend initially starting the engine with your existing conventional ignition system if it is in place and properly functioning. Then upgrade to timing control once you have the EFI installation completed.
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  • Question
    I installed my Sniper EFI, but how do I use my kick down for my C4 transmission?
    Answer
    Lokar makes a Hi-Tech kick down kit to work with a C4 transmission kick down.
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  • Question
    Can I use the Sniper on a roots-type supercharger?
    Answer
    The base sniper kits are not setup for a boost referenced MAP sensor. However, all Super Sniper systems have a threaded boost referenced MAP sensor inlet on the base plate.
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  • Question
    Why does my Sniper idle high after driving on the highway?
    Answer
    It is most likely due to RF interference (radio frequency). RF noise is quite common in older vehicles using original ignition components. It is especially true when using non-resistor spark plugs or solid core plug wires. Using resistor type spark plugs (with correct plug gap), spiral core wires with dielectric grease used sparingly on the boots, and a new distributor cap can help to eliminate potential noise.
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  • Question
    Will the Sniper work with a 200-4R or 700R4 automatic transmission?
    Answer
    Yes, The sniper is designed with a stud location that will provide the proper TV cable geometry.
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  • Question
    Will the sniper fit under the Stock Hood on my car?
    Answer
    The Sniper will have the same height as A Holley carburetor @ 3.25. You will need to measure your available clearance including any air cleaner, spacer and gasket height.
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  • Question
    Why are the screens on the sniper flashing Yellow and Red? Do I need to be concerned?
    Answer
    The Sniper handheld allows you to set limits and warnings. These have generic value when received and will need to be adjusted by the customer based on their individual needs.
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  • Question
    Is the Sniper EFI system capable of monitoring fuel pressure?
    Answer
    No. To monitor fuel pressure, an external gauge must be installed in the fuel supply line and should maintain approximately 58-PSI under all load conditions.
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  • Question
    Can I run my MSD 6AL box with my Sniper EFI?
    Answer
    Yes, but you will need to ensure the rev limiter verification feature is disabled if it is a digital 6AL (if your tach needle sweeps at key on it are enabled. Some early generation MSD 6425, Boxes have this feature and it cannot be disabled). In addition, you must ensure the MSD box is mounted a reasonable distance away from the Sniper throttle body to avoid any type of electrical interference.
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  • Question
    How does the Sniper EFI “Learn?"
    Answer
    The Sniper EFI system looks at the closed-loop fuel compensation required to reach your target AFR. It is reliant on the data acquired by the included wideband oxygen sensor. The learn function will offset the base fuel table until the closed-loop compensation only requires minimal changes. A properly functioning engine and oxygen sensor placement are critical to learning and closed look as well as the longevity of the oxygen sensor.
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  • Question
    How do I know if my Sniper has fully learned? It never gets to 100%
    Answer
    The learn percentage display, is the percentage of learning based fuel compensation. It does not indicate the percentage of learning completed. The closer the base calibration is to the engine s needs the lower the learning percentage will display. I general once fully learned, the closed-loop compensation percentage will be in the 1-5% range.
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  • Question
    Can I use the Sniper on a truck with dual fuel tanks?
    Answer
    Yes, however, you will need to run a dual tank switching valve specifically designed for use with an EFI system that is pressure and flow rated for both feed and return lines.
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  • Question
    How many vacuum ports does the Sniper have and does it have a ported vacuum source?
    Answer
    It has two full manifold vacuum ports on the bottom rear side of the base. There is also a smaller ported vacuum source above these two. In addition, there is a full manifold vacuum source on the front that is shipped with a pipe plug.
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  • Question
    Can I run the Sniper EFI with a draw-through style supercharger?
    Answer
    Not with a base Sniper EFI Kit. However, the Super Sniper EFI throttle body has the provision on the base plate to boost reference the MAP Sensor. The Sniper has an integrated 2-BAR MAP sensor (Manifold Absolute Pressure).
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  • Question
    Will the Sniper work with my aftermarket drop air cleaner base that I used with my Holley carb?
    Answer
    No. You will need to purchase 120-511 (black) or 120-510 (chrome) to use a 14” drop air cleaner base.
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  • Question
    Can the Sniper control my electronic transmission, for example, a 4L80E?
    Answer
    No, the Sniper does not have the capability to control any electronically controlled transmission.
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  • Question
    My truck was an original TBI and already has an EFI fuel system can I use my factory fuel system with the sniper?
    Answer
    No. The Sniper requires more pressure and volume than a factory TBI system did. The Sniper will require 58-60PSI. A minimum of a 255LPH EFI pump is recommended. The Holley 12-920 is an ideal inline solution.
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  • Question
    Can I run the sniper in a 2x4 configuration?
    Answer
    Yes, there are 2x4 sniper options available. Part numbers: 550-531, 550-527, 550-532, 550-528, 550-529, and 550-533.
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  • Question
    My Application has multiple O2 bungs in the exhaust system already, where do I hook up my other sensors.
    Answer
    All of our EFI systems only require one O2 Sensor to operate. Some of our more advanced EFI systems can utilize a second O2 sensor, but the sniper only has the ability to utilize one. You will need to cap off or plug your other ports in your exhaust system.
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  • Question
    I do not have headers on my vehicle, only manifolds. How far do I put the O2 sensor away from my manifold?
    Answer
    The same requirement applies to headers as well as manifolds. We recommend that you install the O2 sensor approximately 6-8” after the merge. Do not install the sensor straight up and down or vertical. Do not install the sensor on the outside radius of any kind of bend in the exhaust system. Follow the diagram shown in the quick start guide for proper install. You should have at least 18-24” of exhaust after the sensor.
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  • Question
    I just finished my installation and my engine will not start.
    Answer
    You must go through the entire set up wizard, ensuring that you highlight every option through the process; once you follow the wizard, you can cycle the key and the fuel pump should prime. You should then check the fuel pressure with the pump running. Line pressure should be approximately 58 PSI and the return line pressure should be less than five, zero is ideal. Make sure the switched 12V stays powered during crank if not, it is likely wired to accessory, and not crank/ run. If the fuel pump primes when you turn the key to accessory, it is guaranteed that is not wired properly. Please refer to our troubleshooting guide.
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  • Question
    When using a Holley dual sync distributor to utilize timing control capabilities does it plug and play with the Sniper EFI?
    Answer
    Almost, You will also need the PART# 558-493 adapter that will allow it to plug into the ignition connector on the Sniper harness. It will also have a pink wire that will need to go to the ignition switched 12V+ that is powered during run and crank.
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  • Question
    What type of Nitrous control can I use with the Sniper Software?
    Answer
    The Sniper EFI features four types of Nitrous control: Wet Progressive/Non-Progressive and Dry Progressive/Non-Progressive.
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  • Question
    What is the difference between the kits with a K suffix for example 550-510, and 550-510k?
    Answer
    The “K” at the end of the part number means that it also comes with a fuel system. This includes 20 feet of 3/8” EFI Hose, in-line fuel pump, post and pre fuel filters, return bulkhead, and all of the necessary fittings and hardware.
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  • Question
    Can I alter my AFR and timing utilizing the sniper's nitrous controller?
    Answer
    Yes, the Sniper’s Nitrous controller can target a specific timing retard and Target AFR if run in a closed-loop. If you do not want to target a specific AFR closed Loop can be disabled.
    Helpful?
  • Question
    How long does it take the Sniper to fully learn?
    Answer
    It varies. The Sniper will never finish learning. Something as simple as weather, temperature, and elevation changes can dictate how much fuel an engine needs. Therefore, every time you drive, the Sniper will keep learning to get closer to your target Air/Fuel Ratio. It will rough in the base table in as little as 10 miles. In generally only takes a few hundred miles for it to get the Sniper fine-tuned, but it is heavily dependent on your driving style. A properly functioning engine with no underlying mechanical or installation issues is critical for proper operation.
    Helpful?
  • Question
    Do I have to buy a new distributor?
    Answer
    No, The sniper EFI will run just the same as a carburetor would. However, if timing control is desired a magnetic pickup or Hall Effect distributor with a phaseable cap or rotor or Holley Dual sync distributor must be used.
    Helpful?
  • Question
    It seems as though my Sniper EFI system is not saving the changes that I have made.
    Answer
    Check the voltage on your pink (switched +12v) with the key off. If this wire is holding residual voltage, even though it seems low, it could be preventing a proper “key cycle” which saves changes.
    Helpful?
  • Question
    Can I use the sniper on a spread bore intake?
    Answer
    Yes, you can as long as the intake is drilled for a dual bolt pattern and will clear square-bore throttle plate spacing. The use of a Weiand Sealing plate p/n 9006 is recommended to ensure there are no vacuum leaks around the base of the Sniper.
    Helpful?
  • Question
    Does the Sniper EFI tune itself?
    Answer
    The Sniper has a self-learning fuel table. It uses feedback from the Wideband O2 to read the AFR (air/fuel ratio). Based on this reading, along with other sensor readings, the system will increase or reduce the amount of fuel commanded, to get closer to your target AFR. Keep in mind that the system will not start its learning process until the coolant temperature sensor reading is around 160 degrees or higher.
    Helpful?
  • Question
    Will the Sniper work with Holley EFI gauges?
    Answer
    Yes. However, it will only support what the Sniper Can display through the handheld and will require the 554-130 gauge module.
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  • Question
    Can I use the TPS signal from the Sniper to send to my stand-alone Trans controller to run an electronic transmission by spicing the wires?
    Answer
    It is not recommended to piggyback signal wires from sensors. This can result in a weak TPS signal to both the throttle body and the transmission and could result in transmission failure or other system damage. It is recommended to use a remote mounted TPS. These are available from companies such as TCI.
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  • Question
    Can I use my Factory Air cleaner with Sniper EFI?
    Answer
    Possibly, You will need to test fit it to see. If it is a drop base air cleaner, you may have to run a spacer under the air cleaner to help clearance the sniper’s body and fuel lines. Or use one of our 14” drop bases.
    Helpful?
  • Question
    What finishes does the Sniper system come in?
    Answer
    Our Sniper EFI comes in three finishes. You have the choice between a shiny silver finish, a black ceramic finish, and a classic gold finish.
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  • Question
    Is the Sniper EFI system capable of running a distributor less ignition system?
    Answer
    The Sniper system does not support this ignition type.
    Helpful?

Sniper EFI Quick Reference Guide

SNIPER EFI HORSEPOWER (NATURALLY ASPIRATED)HORSEPOWER (POWER ADDER)INJECTORS (100LB/HR)BOOST CONTROLBARRELSCFMFUEL PRESSURE REGULATORAVAILABLE AS MASTER KIT
4150 Sniper EFI6505754NO4800 @ 1.5" HGINCLUDEDYES
Super Sniper 6506505754YES4800 @ 1.5" HGINCLUDEDNO
Super Sniper 125065012508YES4800 @ 1.5" HGINCLUDEDNO
Sniper 2x4 4150125012508NO2X41600 @ 1.5" HGNOT INCLUDEDNO
Super Sniper 2x4 4150125012508YES2X41600 @ 1.5" HGNOT INCLUDEDNO
Sniper Xflow8006904X120YES4900 @ 1.5" HGNOT INCLUDEDNO
Sniper XFlow 137580013758X120YES4900 @ 1.5" HGNOT INCLUDEDNO
Sniper EFI 23003502852NO2580 @ 3" HGINCLUDEDNO
Super Sniper 23003506504YES2580 @ 3" HGINCLUDEDYES
Sniper EFI BBD 3502852NO2370 @ 3" HGINCLUDEDNO
Sniper EFI Small Bore 2GC3502852NO2370 @ 3" HGINCLUDEDYES
Sniper EFI Quadrajet5005754NO4715 @ 1.5" HGNOT INCLUDEDYES
Sniper EFI Stealth 4500150012508YES4 1440 @ 1.5" HGNOT INCLUDEDYES

Technical Resources

Sniper EFI
Sniper EFI Software Help File

Sniper EFI Software Help File

Sniper EFI Digital Dash Update

Sniper EFI Digital Dash Firmware V1.0.1

Sniper EFI Troubleshooting Guide

Sniper EFI Troubleshooting Guide

Sniper EFI 4150 Complete Manual

Sniper EFI Installation Instructions

Sniper EFI 4150 Quick Start Guide

Sniper EFI Quick Start Guide

7" Digital Dash for Sniper EFI Instructions

7" Digital Dash for Sniper EFI Instructions

Sniper EFI 2300 Complete Manual

Sniper EFI 2300 Complete Manual

Sniper EFI 2300 Quick Start Guide

Sniper EFI 2300 Quick Start Guide

Sniper EFI Software

Sniper EFI Software/Installer v1.2 Build:17 - Windows Vista,7,8,10 Compatible.

Updated - 1970-01-01

Sniper EFI BBD Complete Manual

Sniper EFI BBD Complete Manual

Sniper EFI BBD Quick Start Guide

Sniper EFI BBD Quick Start Guide

Quadrajet Quickstart Guide

Quadrajet Quickstart Guide

Quadrajet Complete Manual

Quadrajet Complete Manual

Sniper EFI Firmware Revision Log

Sniper EFI ECU and Handheld Firmware Revision Log

Updated - 1970-01-01

Sniper EFI SD Card Contents

Sniper EFI SD Card Contents

Updated - 1970-01-01


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