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Sniper EFI: How To Wire And Setup For A CD Box Ignition


Congratulations on your purchase of the Sniper
EFI system. The Sniper EFI system is compatible with several
popular ignition configurations. In this video I’m going to show you how to
properly wire as well as set up the system for CD box ignition input type. This ignition type does not support timing
control through the ECU and all timing advance or retards will be preformed by the distributor
and/or the ignition box. This ignition option starts with a CD box,
a distributor, and a coil that’s compatible with your CD box or your distributor that
incorporates a 12 volt square wave tac output wire such as this MSD 8360. It’s going to end with your main harness and
the single purple adaptor wire for the ignition. The distributor will need to be capable of
providing a compatible input for your CD box. In the case of our MSD 6425 digital 6AL, it
can be a magnetic pickup or a points input trigger. This MSD ready to run and mag pick up distributor
is just one of the examples. Next you’ll want to want to follow the CD
box as well as the distributor manufacturer’s installation and wiring instructions. For this example I’m going to be using an
MSD 6425 digital 6 box as well as MSD 8551 distributor. If you have an MSD digital 6AL or a ready
to run MSD distributor that has the RPM limit verification feature enabled, be sure to disable
it per the instructions before connecting to your ECU. Otherwise you’ll flood the engine at key on. Form the set up wizard, the ignition set up
icon or the PC software, select CD box as your ignition type, then you want to disconnect
the negative terminal of the battery and remove your fuel pump relay before progressing on
to the next step of installation. So we’ve got our set up complete for ignition
and ECU, now we need to get ready to install the distributor that’s going to work with
our system. One of the things we need to do is we need
to make sure that the crank is in the proper position before we install the new distributor. In this case we need to bring it up to top
dead center at 0 degrees right at TBC for this type of installation. One of the ways you can do that and make sure
your on the right stroke on the compression stroke is to remove the number one sparkplug,
stick your finger in the hole, and pull the engine over as you approach number one and
see if your picking up some pressure. If you are you know your on a compression
stroke. Another thing you can use, and it’s one of
my favorites, is this little tool here and it’s a top dead center whistle. You would screw it in place in the number
one plug hole, and the neat thing about this is as your coming up on a compression stroke
it’s going to give you an audible whistle that’s going to let you know your on compression. The other reason I like this is it’s going
to allow me to confirm that my top dead center pointer is accurate to my balancer because
as I bring it around to zero, when I hit zero it’s going to stop whistling. I can go past it at that point and we don’t
get a whistle. What that’s going to allow you to do is confirm
that the balancer and the pointer match, it’s also going to allow you to determine that
you didn’t run into a situation in where the outer shell has lost it’s grip on the elastimer
and it’s actually slipped. That happens a lot with older balancers and
if you determine that that’s happened, you want to go ahead and replace the balancer
before proceeding. Once the engine’s set back up at top dead
center we can proceed with the rest of the installation, so we’re going to go around
and I’m going to take the old distributor out. So we’re ready to take out our old distributor
and before you do that you want to take a little bit of compressed air and blow the
area clean around the distributor, the last thing you want to do is pull out your old
distributor and have a lot of debris fall down inside the engine, just not going to
be a good thing. With the old distributor removed, we can get
ready to install our new unit. Before you install the distributor there’s
a couple of things you want to do and one of them is a dry check and by that what I
mean is we’re going to put the distributor in, we’re not going to worry about lubricating
it, we’re not going to put a gasket on it, we’re just going to drop it on in and we’re
going to make sure that the base of the distributor seats up against it’s mating surface, in this
case the intake manifold. If we were to check it and it’s raised that
would indicate that we have an interference issue and it’s usually where the distributor
is bottomed out on the oil pump drive. What we’ll cause this usually is going to
be a situation where either the intake, the block, or the heads have been machined and
that brings everything a little bit tighter and it messes up the factory tolerances. If your distributor has an adjustable slip
collar you can simply readjust it to take up the deviation. If not one of the simple things a lot of times
you can do is just put in an extra distributor mounting gasket and it will act like a skin
to help rectify that situation. If it’s not bottoming out, you need to correct
that before proceeding, other wise you will damage your engine. Once you’ve confirmed that the distributor
will dry fit properly, your going to lubricate the gear, make sure that the gear is compatible
with your camshaft, depending on your cam design and the materials it’s made out of
it may require a bronze gear. If your not sure what your cam requires, contact
your cam manufacturer and they’ll be able to give you some clarity on that. Once you’ve determined that you’ve got the
right gear, you can install your gasket and lubricate the gear, if the distributor has
already been run in with the engine and your going to start it in a pretty reasonable time
frame, you can coat it with some engine oil. If it’s never been run in or the engine is
going to sit for a while before the initial start up, your going to want to go ahead and
coat that liberally with quality molly lubricant before you install it. When you go to install the distributor, look
where the rotor is pointing. You want to install the distributor so that
lines up with the area that you want to be number one on your cap. If you go to install the distributor and there’s
some interference, maybe you have a vacuum advance canister that hits the intake manifold,
don’t get too worked up about it, you can simply pull the distributor up, re-locate
it where you need it to be, and drop it back in. The rotor in this case isn’t pointing where
you want it to be, in it’s just a regular mag pickup distributor and the vacuum advance
or something ends up out here, you can pick it up and you can re-adjust that so it lines
up in the direction you want that tower to be for number one. Once you get that installed, you can go ahead
and take your distributor hold down, re-install the hold down, and install your cap. You want to pay attention to the rotor location,
you may want to put a little mark on the side of the distributor body and that will just
help remind you when you get that installed that this is going to be your number one terminal. I’m going to go ahead and lock the distributor
cap down. This would be a good time to install a fresh
set of spark plug wires as well as a fresh set of spark plugs. You’ve gone through this much effort, you
don’t really want to put it back together with some old parts. Put a fresh set of plugs and wires in it and
you’re not going to have any issues with it as you move forward. Once we get this done, we can proceed with
the rest of the wiring in the system. In this case we have a mag pick up coming
out of the distributor, and since the distributor and the ignition box are going to be handling
all the ignition and timing controls, nothing’s going to be wired from the distributor directly
to the ECU. We’re going to connect our mag pickup to our
digital 6 box. The 6425 box comes with this handy extension
and everything will really plug together, the connectors are keyed in a way that you
can’t plug them in incorrectly. So we go ahead and install the connector and
this will connect between your CD box and your distributor. At this point you need to connect the output
from the TAC output of the CD box to the ECU and that’s where this handy little adaptor
comes in to play. So you would connect the loose end of the
purple wire to the TAC output lead of your ignition box or if you have a ready to run
MSD distributor with a 12 volt square wave TAC output, it would also connect to the gray
loose TAC output wire that distributor. We’ll connect that to our purple adaptor and
then on the main engine harness from our Sniper ECU or Sniper throttle body you find a 2 pin
connector that has a mating green and purple wire, one of them will be marked crank input
positive and the other will be marked crank input negative and you simply connect the
two to the ECU. When your dealing with a CD type of ignition
system, never under any circumstances hook the yellow wire up to the TAC output of the
MSD box, or to the coil. If you connect the yellow wire to the system
with a CD ignition you’re guaranteed to your going to destroy your ECU so you just don’t
want to do that. With our phasing complete, our wiring complete,
we’re going to go over to the vehicle and we’re going to do some start up checks. I’m going to re-install the negative cable
to the battery but I’m not going to put the fuel pump relay in yet, we’re going to do
a couple of initial checks before we get to that step, so we’ll go on over and we’ll take
a look at the car and we’ll go one step further. Before we try to start this engine we want
to do some pre-start checks. One of the things that we’re going to do is
confirm that we not only have the distributor synced correctly, we’re going to make sure
it’s wired properly and also we want to make sure that it is set up properly in the ECU. To make sure that it’s properly wired and
properly set up, we’re going to go ahead and look at our monitor on our hand held and pull
up one of the variances RPM and just to key on it should say stall. When we crank it it should show RPM if everything
was done properly. So it showing RPM so we know that we have
it wired correctly and set up properly. At this point we want to go ahead and check
our timing, we want to make sure that it is phased correctly. We’ve confirmed that we have cranking RPM
input to the ECU but before we put fuel back on this thing when we try to start it up,
I want to double check the cranking timing to begin with. Every engine is going to be a little bit different,
but normally you’re going to be somewhere in the four to fifteen degree range so I’m
going to grab my timing light, have a buddy crank it over, we’ll see what we’ve got. Go ahead and turn it over! Alright! Cranking time is right about 10 degrees, it’s
really where I wanted it to be. If you find that the timing’s not in line
where it should be, you can make some simple adjustments to your distributor at this time. You want to make sure that cranking time is
in a safe range before you try to start the engine. Now that we’ve got that checked out I’m going
to go ahead and put the fuel pump relay back in it, we’ll come back and try to start it
here in a second. We’ve got our fuel pump relay back in, we’re
going to go ahead, prime the system, try to start the engine, when it’s at idle we’re
just going to double check our idle timer just to make sure everything’s ok before we
proceed. Go ahead and crank it over. Fires up, it idles, our idle timing is right
where we want it so we’re good to go for this application. For more Sniper EFI tech tips and videos,
go to Holley.com

9 thoughts on “Sniper EFI: How To Wire And Setup For A CD Box Ignition

  1. Very helpful video.
    Questions though, I have an old MSD 6AL that isn't digital. Does it function and connect the same as the one you show?
    Also, can I connect the ign hot wires from both the MSD 6AL and the Sniper's to the same wire from my ign switch?
    Finally, what is the P/N of the cable at 8:03?
    Thanks in advance.

  2. There has to be a way to do this with a stock HEI or any other distributor. I shouldn't need to spend an extra 1000.00 dollars to do this. Maybe an old Mallory with the same three wire hook up. Seems like there is something simple they don't want to tell us so we spend money on non needed components.

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