Congratulations on your purchase of a Sniper EFI system.
The Sniper EFI system is compatible with several popular ignition configurations.
In this video I am going to show you how to properly wire and set up the system for a
Holley dual sync distributor using the ECU to control timing
All timing advance or retard functions will be performed by the ECU.
This ignition option starts with a Holley dual sync distributor.
Dual sync adapter part number 558-493 , a Sniper coil driver module or a CD Box, and
a compatible coil.
The ECU needs to receive a clean input signal, vehicles that have excessive Electro-magnetic
interference ( EMI ) or RF noise issues can compromise these signals, as well as other
control circuits resulting in poor performance or drivability issues.
Proper grounds, spark plugs, ignition wires and wire routing are critical for trouble
free operation.
Non resistor spark plugs and solid core wires may have worked with your carburetor but they
will not work with EFI.
A common sign trouble is if your radio whines with the engine running.
If you have EMI or RF issues they need be corrected.
Before we dive into the mechanical side of the installation we need to program the ecu
for the proper ignition type.
From the set up wizard, ignition setup icon or the PC software select Holley dual sync
as your ignition type.
If you are manually setting it up, the reference angle should be set to 50.
The inductive delay set to 100 and the dwell set to 2ms now that that’s complete lets
dive into the mechanical part of the installation.
Before you get started you will need to disconnect the negative battery terminal.
And remove your fuel pump relay
Next You will need to properly install and phase the distributor pick up.
If your removing an old distributor remove the ignition wires and use some compressed
air to clean the area around the distributor mounting location before pulling the distributor.
You don’t want any debris falling into the opening when you remove the distributor
Remove the spark plug from the number one cylinder and turn your crankshaft in the direction
of rotation until you are approaching number one on its compression stroke.
You can stick your finger in the hole as you rotate the crank until you feel pressure to
confirm you’re on the compression stroke or you can use a top dead center whistle.
I like the whistle, because not only will it identify the compression stroke it will
also give you a pretty quick way to validate that your TDC pointer and balancer mark are
in check.
Over the years I have seen many mismatched balancers and pointers or old balancers that
have allowed the outer shell to slip giving you a false reference point.
Once you have confirmed you are approaching number one on the compression stock turn the
crank to 50 degrees before top dead center If your balancer is not indexed you can measure
the diameter then multiply it by 3.14 divide that total by 360 and multiply that total
by 50.
Or skip the math and simply follow this chart for common balancer diameters and measure
this distance from your zero mark to find your 50 degree reference point.
Marking the reference distance on a piece of masking tape is handy for this.
Next you will need to install your distributor.
Make sure that the gear is compatible with your camshaft and dry fit it without the gasket
installed.
If it bottoms out without making contact to its mating surface, you will need to remedy
the situation.
This is common if the block, heads or intake have been machined.
The tall deck Chevrolet 565-104 dual sync has a slip collar so you can adjust it, or
most of the time a second gasket will be enough to take care of the situation.
If your cam and distributor have been previously run together and you are going to be starting
the engine right away, a generous coating of engine oil on the gear should be fine.
If not coat the gear with a quality moly lubricant.
point the rotor in the general direction you want to position the #1 plug wire and install
the distributor.
If the oil pump drive does not line up, you can turn it with a long screw driver or an
oil pump priming tool.
If you do not like the location or you find that something on the distributor interferes
with something on the intake you can pull the distributor and reposition it as required
just remember to keep the rotor pointed n the general direction you want number one.
now line up the rotor pointer with the black crank position sensor.
Gently snug the hold down allowing you to still rotate the distributor.
Connect the 558-493 to the distributor and the two wire green and purple connector in
the main harness the wires will be marked Crank input Positive and Crank input negative
and wire the loose red wire to the ignition run circuit of your ignition switch.
Reconnect your negative battery cable and turn the ignition to run but do not crank.
Both LEDs should be lit in the distributor.
The LED closest to your crank sensor indicates crank position
Slowly turn the distributor in the direction of rotor rotation until the light turns off
then turn it back the opposite direction until it just turns back on and lock down the distributor.
Now you can reinstall your ignition wires.
Now would be a great time to pick up a new set and some fresh spark plugs at the same
time.
Next locate the white point output wire in the input / output harness and securely connect
it to the point input wire of the Sniper coil driver or CD box.
This is usually a white wire as well but always check the CD box manufacturers instruction
for proper wiring.
Always use proper connection practices with quality terminals and crimping tools.
It’s also a good idea to seal these connections with adhesive lined shrink tube.
Never connect the yellow wire or any other wires from the EFI system to the coil wires
on a CD system or severe ECU damage will result.
crank the engine over and verify that you are showing an RPM signal on the handheld
or the data monitor screen in the software.
Next Select the tuning icon then the system icon on your hand held and select static timing
check.
Move the slider to a base value, I generally recommend 15 degrees and select set.
using a timing light confirm that your cranking timing is at your static timing
of 15-degrees.
It is important to note that you will need to reset the static timing if you cycle the
ignition off then back on, as this automatically shuts it off.
If it’s not correct, rotate the distributor slightly until it matches
Once it’s correct reinstall the fuel pump relay and start the engine.
Once again set the static timing set to 15 degrees and confirm that your timing is still
at 15 degrees.
If you’re thinking this is a redundant timing check you are correct, I would rather check
my timing twice then hurt my engine once.
You can
then select close on the static timing screen and it will allow the ECU to resume control.
It is normal to see the timing fluctuate at this point.
This
is caused by the idle timing control using the timing
to help stabilize your idle speed.
You can know set your desired timing through the
hand held
or the pc software.
For more helpful
Sniper EFI tech tips and videos go to Holley.com