How To Install Sniper EFI BBD for 1971-1986 Jeep CJs

By: Jeremy Stoermer | 04/22/2019 < Back to Motor Life Home

It’s no surprise that Sniper EFI has taken the market by storm, and replacing that old carburetor with EFI, has never been easier. Now you can give that old jeep of yours the driveability and performance benefits it deserves, with sniper bbd from Holley. And because I want you to know just how easy it is to get all those benefits and more out of your jeep, I’m going to take you step by step thru the complete install using our CJ. It’s 84 CJ7 with the original 258ci inline 6, sporting a Carter BBD carb. Holley’s Sniper EFI BBD kit was designed for use on 1971-1986 Jeep CJ’s with this engine combo, and although you probably won’t see these numbers from your trusty inline 6, a pair of 100 pound per hour injectors, make Sniper EFI BBD more than capable of supporting up to 350 hp naturally aspirated. Watch the video above as we walk you through the whole installation process!

  1. If any of the lines are damaged or appear damaged, now is a good time to take care of them!
  2. Clean the gasket mating surface if necessary and install the new base gasket. Some models may have a spacer like this one, if yours does be sure no install a gasket on both sides of the spacer.
  3. Before you install the sniper throttle body, it’s a good idea to install the new air cleaner bail with the included hardware. This lessens the chance of losing a screw in the engine bay or worse yet, down the intake!
  4. Once you’ve got the bail secured we can set the throttle body on the intake and install the 4 nuts to secure it. Tighten the nuts in a criss-cross pattern and torque to 60-80 inch pounds.
  5. While were here we can reinstall the throttle lever, simply snap it into place and check for any binding or interference issues before proceeding
  6. Carefully reconnect the vacuum lines we removed earlier from the carburetor. Plug-off any vacuum sources that will not be used on both the sniper throttle body and the engine.
  7. Sniper EFI supplies a coolant temp sensor which needs to be installed into a 3/8” NPT port in either the intake manifold or cylinder head. To avoid making too much of a mess, you can drain some of the coolant from the radiator before removing the old sensor or plug. I’m going to install the sensor in the intake for this particular vehicle. Never install the temp sensor in the thermostat housing or any location that will not see a constant flow of coolant. make sure you apply some thread sealer or thread tape before installing the sensor and take your time. You don’t want to cross-thread or over-tighten the sensor. Connect it to the appropriate lead from the throttle body when done!
  8. Next you’ll need to locate a good position for mounting the wide band O2 sensor in the exhaust. It should be located as close to the engine as possible while providing a good average of all cylinders. If your Jeep has a header the sensor needs to be 1-10 inches after the collector. Remember the O2 sensor needs to be positioned at least 10 degrees from level and at a downward angle. This prevents any condensation from building up on the tip, and possibly damaging the sensor.  I’m going to drill into the exhaust pipe here and use the included no weld gasket and flange. We can now install the O2 sensor and tighten then connect it to the lead coming from the throttle body. 
  9. Now on to the electrical connections. You’ll need a clean dedicated 12v switched source. It needs to have 12 volts while cranking and with the key in the run position. Run the pink wire from the sniper throttle body to this source and connect with the appropriate electrical terminal.  The solid red and black wires will need to be run directly to the corresponding battery terminals. Never not run them through a switch , relay or distribution box.
  10. The heavy blue wire is used to power our fuel pump. It’s powered by a relay and can be run directly to the positive terminal on your fuel pump.
  11.   There are several options when it comes to supplying fuel to the sniper throttle body. For this install I’m using the Sniper replacement fuel tank and a Holley direct fit efi pump module. You could also use an inline style pump you can put your own kit together using your choice of pump and fuel line from our website. But To make it easier, we put together a Sniper master kit that includes the inline pump, vapor guard fuel line, fittings and mounting hardware. If your jeep is on the serious side and you have a fuel cell, we have bolt on EFI fuel pump modules to fit most fuel cell bolt patterns. Or you can use one of our retrofit in-tank modules to finish the job. 
  12.  Once you’ve located a suitable mounting location for the pump you can terminate the blue power wire and connect it to the positive lead on the pump. You’ll also need to run a wire from the negative terminal of the pump to a clean ground on the chassis. Since I'm installing the sniper fuel tank and EFI module, I'll need to install the pump module in the tank first. I like to use o-ring lubricant or some vaseline on the sealing o-ring. Line up the indexing pin on the pump with the index hole on the hydra mat and press firmly on the filter base until it is fully seated. Now slowly feed the filter into the tank making sure you don’t cut or snag it on the tank opening. Once the filter and pump assembly are in the tank, you’ll have to remove the 2 screws holding the fuel level sender and float arm to the module. Now feed the float into the opening and reposition it so the screws align with the mounting tab on the module again. Then tighten both screws. Next we can plug in the included harness lead and make the connections for the power to the pump using the heavy blue wire from our sniper harness. Make sure you use a clean chassis ground and since the Holley module also includes a fuel level sender we can connect it to the factory wiring for our dash gauges.  
  13. We need to run a supply and return fuel line to the sniper unit in the engine bay. I’ll start here at the tank and using the correct EFI rated clamps on both fuel lines ill install and secure them to the tank. Make sure you are using EFI rated fuel lines and clamps.
  14. When supplying fuel to any EFI system we recommend a 100 micron pre filter and a 10 micron post filter. Since the HydraMat on our Holley pump module acts as our pre filter, I only need to add this 10 micron filter to the supply line. Once again I'll secure it using EFI rated clamps.
  15. Now I can route and secure the fuel lines along the frame rail, working my way up to the engine bay. Be sure to avoid and moving parts or high heat areas that could compromise the fuel lines integrity.
  16. Once you have the fuel lines safely secured and run up into the engine bay we can cut the excess off and install the fittings onto the Sniper throttle body and tighten.
  17. Let's focus on the ignition system now. Sniper EFI will work just fine with the stock mechanical distributor and inductive coil. But if you want to be able to control ignition timing, you’ll need to upgrade to a magnetic or hall-effect style distributor. We have several distributor options from MSD, Holley and Sniper for timing control and complete wiring instructions can be found on our website.  
  18. I will be installing a Hyper spark distributor, cd ignition box, and a coil on this jeep. Since HyperSpark ignition components were designed to work with the Sniper EFI units it's an easy install. 
  19. The first thing you’ll need to do is to rotate the engine to top dead center of the compression stroke on the #1 cylinder. To find the #1 cylinder just trace the plug wire from the front cylinder ( they’re number 1-6 from front to back) back to the distributor and put a mark on both the cap and housing. Remove the cap and slowly rotate the engine in the direction of normal operation until the rotor is aligned with your mark. We need to verify top dead center on the harmonic balancer. The timing indicator should be real close to the o mark on the tab, if not continue rotating the engine until they both align. 
  20. Now remove the coil and plug wires as well as any vacuum lines that may be attached to the distributor. It’s a good idea to wipe or blow off any debris around the base of the distributor that might fall into the engine when removed. Loosen and remove the bolt and distributor hold down. Next gently lift up on the distributor housing to remove it. Note that the rotor rotates slightly when its removed, this is due to the helical cut gears and you’ll have to take this into account when installing a new distributor.
  21. Install the new gasket to the base of the HyperSpark distributor, if needed you can apply a dab of silicone to keep it in place. Coat the new gear with some engine oil or if the engine is new or has just been rebuilt, apply some moly grease to the gear instead. Position the rotor so it's pointing in the same direction as the plug wire for the #1 cylinder on the old distributor was, remember the rotor will rotate slightly when installed so you’ll have to compensate for this. If the rotor does not land in line with the location for the #1 plug wire, you’ll have to remove it and try again. In some engines It may be necessary to rotate the oil pump shaft slightly to get it to align with the bottom of the distributor. To do this you can use an oil pump priming tool or long flat blade screwdriver.
  22. Once you have the distributor fully seated and the drive gear and oil pump have meshed, we can place the clear distributor cap included in the kit over the rotor. Now slowly rotate the distributor housing until the clear cap drops down into place, this step phases the distributor housing. Finally we can reinstall and tighten the distributor hold down.
  23. Once the distributor alignment procedure is completed, your rotor should be pointing in the direction of the terminal for the#1 cylinder spark plug when the distributor cap is installed. To make this easier, I make a mark on the housing that I can match up to a terminal on the cap. Go ahead and install the new distributor cap, secure it with the screws, and then install the #1 plug wire. Go ahead and install the rest of the plug wires following the correct firing order and distributor rotation. On jeeps with a 258 engine, the firing order is 153624 in a clockwise direction. Note that the stock plug wires will not work on the new cap, your plug wires will have to be swapped out for a set that will work with the HEI style terminals. Once all the wires are installed, use the supplied wire retainer to keep them in place. 
  24. Next you’ll need to locate the 3 pin wiring harness that’s supplied with the HyperSpark distributor. Plug the 2 pin connector from the distributor harness into the corresponding 2 pin connector found on the sniper main harness. The connectors are keyed and the green and purple wires will match up. 
  25. Now plug in the 3 pin connector on the distributor into the 3 pin connector in the harness. Next we need to connect the pink wire to the same switch 12v source we connected our pink wire from the sniper main harness to earlier.
  26. Installing a HyperSpark cd ignition box and coil are not required to run sniper EFI, but they can definitely provide some added benefits to your jeep, and can be easily installed with our plug and play connections. 
  27. Locate a safe and convenient location to mount your sniper cd ignition box away from high heat and moving parts. 
  28. Connect the main wire harness to the box and run the red and black wires directly to the battery. 
  29. The HyperSpark ignition needs a points output signal, this can be obtained by utilizing the aux input/output harness that comes in the sniper EFI kit. Plug in the harness to your sniper EFI and connect the white points output wire from the sniper throttle body to the white wire on the HyperSpark ignition harness. Any unused wires on the harness can be unpinned and removed or simply tied up and out of the way for future use.
  30. Run the light gauge red wire that’s on the connector next to the white wire to the same switched 12v source we used for the pink wires from the sniper EFI and HyperSpark distributor.
  31. Now we can mount and plug in the HyperSpark coil.  
  32. The HyperSpark ignition can also be used with most stock and aftermarket coils. If your coil does not use a TFI style connector, simply cut it off and install the correct ring terminals then secure them to the appropriate terminals on the coil. (Orange=positive and brown/orange is negative) if your vehicle has a ballast resistor in-line with the coil wiring, its recommended that you bypass it or remove from the system. Since I'm not using the coil that’s in the stock location, ill terminate the wires and remove the coil.
  33.  We’re now ready to launch the start up wizard, and this can be done using the handheld touch screen, so we’ll first need to reconnect our negative battery terminal so we have power.
  34. But before we do this it’s a good idea to flush the fuel lines of debris, this can prevent damage to the injectors and other components. Simply remove the fuel supply line from the throttle body and place it in a petroleum safe container to catch any debris that may have entered the lines. Now we can start the wizard
  35. Turn the key to the run position but do not crank or attempt to start the engine at this time.
  36. From the home screen select the wizard icon from the main menu, then select the sniper system that you are installing. BBD in this case.
  37.  Next you will have to select the number of cylinders that your engine has and select next
  38. Use the slider bar to input the cubic inch displacement of the engine, 258ci for our engine, press next
  39. Now we need to set the desired idle speed for coolant temperatures above 140 degree Fahrenheit. Use the slider to set the target rpm and press next
  40. The ECU also needs to know the cam type, for most street and street performance camshafts the stock/mild selection is what you will use. Select the cam type and then next.
  41. This step is to select the type of ignition system you will be using? As I talked about before, sniper EFI will work with stock and performance inductive coils, and cd boxes for installations that are not using timing control. If you want to control ignition timing you’ll need a magnetic or hall-effect distributors. I’ve installed the HyperSpark distributor and ignition system so I’ll select the HyperSpark option. click next
  42. Sniper also needs to know if you plan to control ignition timing? I am so ill select yes then next
  43. Use the cursor to select the total timing at wide open throttle, I'm going to set ours at 32 degrees
  44.  After you have answered all the questions in the wizard, a calibration will be created for you. Press the start button to send the calibration to the ECU and wait for a screen to appear indicating that the file has been uploaded.
  45. Once the file is uploaded you will need to cycle the ignition key off, then back to the run position again. You should hear the fuel pump prime for app 5 seconds. I like to go ahead and cycle the key another 3-4 times, pushing fuel and any debris through the fuel lines and into our catch container. 
  46. Once you're satisfied that the fuel lines are clear, you can reattach the supply line to the throttle body and tighten the fitting.
  47. One more cycle of the key should then pressurize the lines, and now is a good time to thoroughly check the fuel system for any leaks.
  48.  Before we can attempt to start the vehicle we need to verify that the system sensors are operating properly. To do this turn the key to the run position and from the home screen select the monitor icon, then the monitors screen. An icon named initial startup should appear, select this icon. With the key in the run position and engine not running the following sensors should read as follows.
  49. ∙ Engine RPM should show “Stall!”, once you crank the engine it will show actual engine RPM 
  50. ∙ TPS (Throttle Position Sensor) – Should read 0. If you Slowly depress the throttle to wide open. It should read between 85 and 100% at wide open throttle. If it does not, you’ll need verify your throttle linkage is allowing full travel of the throttle arm.
  51.  ∙ MAP (Manifold Air Pressure Sensor) – Should read from 95-102. At high elevations, it could read as low as 75. 
  52. ∙ CTS (Coolant Temperature Sensor) – reads engine temperature and will read ambient temperature until the engine is started
  53.  ∙ IAC (idle air control) Position – I will this when we get to the Idle Setting and Throttle Plate Setting section.
  54. ∙ Battery – Will show battery voltage, and You Should have 12.0 volts minimum.
  55. If any of theses sensors do not read properly, the issue must be resolved before proceeding or attempting to start the engine
  56. If you haven’t done so already, Now is a good time to go back and make sure you have all the wiring routed away from moving parts and high heat areas and that the connections are secure. Wrap up and zip tie ally loose or excess wires, you can also de-pin any unused wires in the input/output harness. 
  57.  You’ll also need to perform the pre-start checklist that’s outlined in the installation manual!
  58. With the handheld still on the initial start up screen, turn the key and crank the engine over. Watch the rpm parameter, it should go from stall to syncing then to registering rpms as the engine fires and is running. If the engine does not fire you’ll need to follow the flow chart in the sniper EFI troubleshooting guide found at
  59. If the engine runs but you find that the idle is too low and it wants to stall out, you may have to open the idle speed screw on the throttle body slightly.
  60. Once the vehicle has started and is idling, double check for any fuel or coolant leaks.
  61. We also need to verify the ignition timing using the touchscreen and a timing light. First we need to lock the static timing. Select the timing icon from the home screen, then select system, then static timing.  Slide the cursor to 15 degrees and click set, now you’ll have to connect your timing light and verify that you have 15 degrees of timing at the balancer. If it does not read 15 degrees before top dead center you will have to loosen the distributor hold down and rotate the distributor until the values match. Don’t forget to re-tighten the hold down when you finished. Now that we have verified the timing we can click clear on the handheld and sniper is now controlling ignition timing .  
  62.  Once the engine coolant has reach a temp of at least 160 degrees, we can adjust our idle speed to the rpms we selected in the start up wizard. To do this, select the monitor icon from the home screen, then multi-gauge, and finally the sensors tab. With the vehicle in neutral and parking brake applied, rotate the curb idle adjustment screw open or closed until the IAC reading is between 2 and 10 percent. If the TPS registers above 0 you’ll need to cycle the ignition switch turning the engine off and back on to reset the tps to zero. 
  63. Now that the idle is set we can install the factory air cleaner. Install the new sealing gasket included in the kit on the throttle body, align the air cleaner assembly on the studs and tighten both wing nuts.
  64. Congratulations, With the stock air cleaner installed your now ready to hit the road, and let Sniper self tune while you enjoy the drive!
  65. Don’t forget to refer to our quick start guide and follow the instructions found under the first drive section.
  66. Try to perform your first drive in an area without much traffic and take a friend along if you can, they can watch the gauges while you concentrate on the driving. 

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