Holley Sniper EFI Self-Tuning Kit Shiny Finish

It's been 26 years since the last carbureted cars were produced in the United States and while we've given our 1968 Bronco a lot of modern amenities, it still has a carburetor. When we originally built it, we did plan on going with fuel injection, but because of time constraints, we ended up throwing a carburetor on it and today we're going to improve the performance and efficiency of it by installing this Holley Sniper EFI Self-Tuning Kit.

This Holly Sniper EFI Self- Tuning Kit is going to replace the outdated carburetor on our Bronco. It features an internal ECU map sensor and a fuel pressure regulator, for an easier install and it can even self-tune. With this EFI kit, we won't ever have to worry about altitude, changing out the jets, cold starts, chokes and it's going to make the overall idle and performance significantly better.

This kit is a direct-fit replacement for your carburetor and includes everything you need for it to work, but it does require a return fuel system, which can be purchased separately.

Tool you'll need for this installation: A good set of sockets and wrenches, tools for drilling and also wiring.

The very first thing we're going to be doing to the Bronco for this EFI kit is draining the gas tank. Since we have to do a return line to the fuel tank, we have to drop it and drill into it, so we're going to drain the gas tank first. To drain the tank, all we're going to do is take off the fuel line from the tank that goes to the fuel pump and so we don't make a mess, we're going to clamp the hose shut.

If you'll notice, our Bronco already has an aftermarket electric fuel pump on it, but we will be replacing it for this Holly kit. Then un-clamp the hose. Then you can just let it drain onto the tank. When you're doing this, be mindful of how much fuel is in your gas tank. We're thinking ours might have over ten gallons in it, so you might need a fair amount of extra gas tanks to hold all of the fuel.

The tank's empty now. We got the boring part out of the way. We're going to put the hose back on the pump and then move up to the front of the truck.

With the fuel tank empty, we can begin the process of removing the carburetor. Before we get any work done, we're going to disconnect the negative battery terminal on the battery, just to be safe. Disconnect the throttle cable. This Bronco actually has a throttle positioning sensor we have to disconnect too. We just need to push these tabs right here, to release it from the bracket. Disconnect all of your vacuum lines. Disconnect the fuel line and pull off these connectors.

Now we can actually remove the carburetor from the intake manifold. Remove all four nuts to remove the carburetor. With the carburetor off, make sure the mating surface is nice and clean and install the new gasket. Install the new fuel injection unit with the logo facing the front of the vehicle and reinstall the four washers and nuts to hold it in place.

Before we install the throttle cables on the EFI unit, we have to transfer over these pivot joints. Install the pivots onto the Holly EFI unit. We're now going to reinstall the throttle positioning cable. Reinstall the throttle cable.

It's time to install the cooling temperature sensor for the Holly EFI unit, but we ran into a little issue that most of you probably won't run into. We have an aftermarket coolant temperature gauge right here and this is the only port available on the intake manifold, so we're going to remove this sensor and install the Holley sensor and then relocate this.

Put some thread sealant or thread tape onto the sensor, then install it in the intake manifold. Grab the purple connector and then plug it into the sensor.

We're now going to install the fuel hose onto the fuel injection unit with this A-End fitting and I'm going to show you how to put this together. You're going to take the fitting apart and slide this sleeve over the hose. Then you're going to lube up the barb right here with some WD-40 or some kind of lubricant, then you're going to push it on.

This is fuel injection hose, so the hose is very tight and it's going to take a lot of force to push this on, but you're just going to push it together and you'll end up with this result.

Connect the hose to the inlet of the fuel injection unit. All right. The EFI system knows what's going on. It included an oxygen sensor that we have to install. Grab the connector that's on the EFI unit and plug in the oxygen sensor. Then you need to find a location to mount it. You want it after the header collector, so you're gauging all of the cylinders on that side.

Ideally, it would be for all eight cylinders, but this is a dual exhaust and we don't have enough wire to out this after all eight cylinders collect, so we're just going to do it on bank one and you want to install it in an orientation to where it's ten degrees or more above being horizontal in order for moisture to drain off of it, so the sensor doesn't get damaged.

We picked a location on our pipe, right here and it comes with an O2 sensor bung that we're going to clamp onto here, but we need to drill a hole in its pipe first. We marked our hole, now we need to drill it out to three-quarters of an inch.

With the hole drilled, you're going to install the provided gasket and then the oxygen sensor flange. Then you're going to put the supplied hose clamps around it to secure it in place. You could also weld a bung on here if you want, but this is included in the kit. Don't tighten the clamps down just yet, in case it gets misaligned.

Then, grab the oxygen sensor and you actually don't need to put any anti-seize on there, it comes with it. Then thread it onto the flange. There we go. All right. Then tighten down the clamps. Tighten down the oxygen sensor.

We can now begin working with the main harness. We're going to start off by running the main connector off the EFI unit, down here under the spark plug wires. Then grab the main connector, plug it in. We're going to mount this relay right here on the wheel well and then we're going to connect the ground and power wires to the battery right here. Then we're going to have plenty of room to connect this yellow wire to the ignition coil.

We're going to use a self-tapping screw to mount the relay, just like that. This yellow wire connects to the negative terminal on the coil right here, but I think we have a little bit too much wire, so we're going to trim it down and then terminate it. Strip it, crimp it, then use a lighter to activate the heat shrink. Take the nut off the negative post on the coil and put the connector on the coil.

It's important to note that if you have an MSD box ignition, you do not want to put this wire on the negative part of the coil. Only do this if you do not have an MSD ignition box.

Now we're working on this pink wire. This is the main switch wire for the whole system. It needs to be connected to a 12V ignition source and we have a 12V ignition source right here. It needs to be its own clean source. It can't be connected to anything else. We're just going to connect the pink wire to here and then move onto the next one.

The pink wire's just a little bit too long, so we're going to cut it to an appropriate length and connect it to the ignition source. At this point, if you want to, you can permanently install this unit right here. Simply grab the connector that's on the EFI unit and plug it in.

Then, if you want to permanently install this, you can run the wiring through the firewall and then mount this somewhere on the dash or in the interior somewhere. However, you don't need this hooked up at all times, so we're not going to do that.

We're going to go for a nice cleaner look on the inside, so we're just going to hook this up for monitoring when we first do the install, but we're not going to leave this permanently installed, so we're not going to run the wiring. But, if you do, just simply find a grommet in the firewall and if you don't have a grommet, just drill a hole and put a grommet in and run the wire.

This red wire on the main harness has to go directly to the positive terminal on the battery and this black wire has to go directly to the negative terminal on the battery. We're going to use the supplied connectors to directly connect them to the battery. We're still going to leave this disconnected for now, but we're finished with this part.

We're finished with the wiring for this Bronco now, but you're probably wondering what all this extra wiring is. This is an optional harness that we will not be using for our truck, but this is for if you want to use it for electric fans or your AC fans. Since we already have a switch for that, we don't need it.

This blue wire is actually for the fuel pump. If you don't already have an electric fuel pump set up, this has a built-in relay for it and this is to power the fuel pump, so we won't be needing this as well. Then, this wire is for if you have an MSD box type ignition system and we don't have that, so we will not be using this connector either.

With all of the wiring complete, we're now going to reconnect the vacuum lines, but we needed to do some modification to our current setup. We needed to get a longer vacuum line for the distributor because all of the fittings were relocated to the rear of this unit. Our fittings were on the front, so we need a longer vacuum line for the distributor.

Now, our PCV and booster line need to go to the EFI unit, but there's only one big port, so we needed to get a T-fitting to put these two hoses to it. Both of them are a little bit too long, so we're going to trim them down to make them fit nice. Install the T-fitting. Then take one of the sections that we cut off, then use that to connect it to the EFI unit, just like that. Now we can connect the distributor vacuum line.

All of the wiring up front is complete and now we can start working on the fuel system. This Bronco does need a return fuel line for this to work, so the first thing we're going to do is disconnect all of the hoses again and drop the tank. We did drain this earlier, but we're going to be cautious just in case there's any more fuel left in there. There's a little bit left.

We also have to disconnect the filler hoses and disconnect this connector to the sending unit. To minimize the mess when I lower this gas tank, I'm going to take a bolt and put it in the hose that goes to the fuel pump, just so no more fuel can come out. With everything disconnected from the tank, you can lower the strap.

We're going to be putting the return line right here on the tank. There's no access panel or anything for this tank. The only thing that there is, is the sending unit right here, so we need to put a nut on the inside of the tank and you don't want it to be too far away from here because you have to get inside the tank to hold the nut, so you want it close to the sending unit or an access panel if you have one. Now we're going to remove it. Be careful not to damage the sending unit.

With the tank out of the Bronco, we can now work on installing the return line. In order to do that, we need to drill a hole in the tank right here, to install a bulkhead fitting. This bulkhead fitting did not come with the Holly kit and you will need to get this if you want to do the return line properly. The bulkhead fitting we're using from Russell is part number 670850 and you will need this to properly do a return line in your fuel tank.

Before you start drilling a hole, you want to make sure where you can install the return line. We've had a lot of clearance issues with this tank. The frame basically ran right here, so we couldn't do anything above this line because there was a frame here and it sat pretty much flush with the bottom of the Bronco right here, so we couldn't do anything up top.

You want to do the return as high as possible, but like I said, we can't really go above this line because of the frame and this is the only opening in the tank. In order to install this bulkhead fitting, there's a nut and a washer that you have to hold on the inside of the tank, so if you were to do this too far away from the opening, you wouldn't be able to hold it.

You need to find out where you can reach around and get an approximate distance of where you would be able to hold this nut. In our case, we're looking at right about here. That's where we're going to drill the hole. That's as high as we can go and also as far away from this hole as we can go.

I'm going to start off drilling the hole just like this, but once I get it started, I'm going to flip the tank up like that, so the shavings don't fall inside of the tank and down here to where I can't get them. If I drill it like this, on the edge of the table, I can get my hand inside of the hole and just wipe out the filings.

We're going to start off drilling the hole with a pilot bit. Now that we've got it started, we can upgrade to our bigger drill bit. It's important to note, you want to get as much or all of the fuel out as physically possible. In our case, we drained all of the fuel out, cleaned it with water and let it sit overnight and made sure it was completely dry before we did any drilling.

Put the longer end of the fitting in the hole, then install the washer and then the nut. See, if you were doing this away from this access hole right here, there would be no way you can do this. To hold the nut on the inside of the tank, you might need a flexible ratchet head like this. Then you get the ratchet head in there, then you can get it on the nut and then tighten it with a wrench. You need to make sure this is tight, so it does seal, but you also don't want to over crank it because these are aluminum.

Reinstall the O-ring for the sending unit. With the bulkhead and the fuel sender in the tank, we can put it back in the truck. Reinstall the tank. Tighten the clamp on the filler hoses. Reinstall the fuel tank strap.

Since this is a fuel injection system and the Holley kit came with a fuel injection fuel filter, we're going to replace this fuel filter with a Holley filter. Now install the Holley fuel filter in the fuel injection line and this filter only goes one way, so make sure you have it orientated right. This flat part with this, I guess, cap section is the outlet and that goes towards the fuel injection unit. Install the clamp on the other hose.

We're going to connect the return hose now. I installed a barb fitting, just like we did on the feed side. We'll just thread it into the return side of the fuel injection unit. There are three feed ports on this unit. There's one here, one here and one here. You can use whichever feed you want, but there's only one return. You have to use the return on the fuel pressure regulator, which is right here.

With the return line connected to the EFI unit, we can just route the hose back to the tank. Since we're converting this to fuel injection, this pump that's currently on the Bronco, doesn't produce enough PSI for it to work properly, so we're going to take it off and replace it with a Holley unit. There might be some fuel left in this hose when you take it off, so be careful.

Un-bolt the pump from the bracket. We're going to cut these wires right here at the fuel pump and lucky for us, now I have wires already ran for a new Holley fuel pump, but if you don't already have an electric fuel pump ran, you will have to run wiring for the new fuel pump. We're going to put the Holley pump right where that fuel pump was. Put the brackets on it and we're going to mount it right there. All right.

Remove the plastic plugs from the fuel pump and install a barbed fitting with thread sealant on each side. We're going to install the first fuel filter. It has to go between the tank and the pump and this little ridge right here has to go towards the engine and the flat side goes towards the tank.

We're in pretty tight quarters here, so we're going to make a little loop to connect this filter to the pump. It's not going to be a straight shot. On this hose, you can use just regular hose clamps, but after the pump, on the pressure side, you're going to need fuel injection hose clamps because of the excess pressure. All right.

With the fuel pump mounted, we're going to connect the power and ground wire. It's important that you get these wires in the right position because if you switch them up, the pump will go backwards. Because this is now a fuel injection system and it's going to see higher PSI, we need to swap out this regular fuel hose, which run from the metal line to the pump, we need to swap it out for fuel injection hose.

Before we finish the fuel feed line, we're going to do the return. Now that we have the bulkhead on the tank, we can thread on this ninety degree fitting and we have our return hose ran, now we're just going to see about how long we need to cut it. It's looking like we can cut it right about here. We have the A-End fitting on, now we can put it on the tank.

You probably won't run into this issue, but the flare that we had on this metal line right here, was too big for the fuel injection hose, so we cut it off and put a compression barb on here. Install the fuel injection hose. Make sure you use fuel injection hose clamps and connect it to the fuel pump and tighten up the clamps.

It's also a good idea to replace any other regular fuel hose you have with the fuel injection hose, so you don't have a leak. The very last thing that we have to do while we're back here is reconnect the sending unit connector. Now you can reconnect the battery terminal, fill the tank up with gas and then check for leaks.

All right. There's no leaks. Everything seems to be good. Now we're going to clean up the wiring. We took off the air cleaner stud from our carburetor and we're going to swap it over to the Holly Unit. They do provide you a stud in case you don't have one.

Now we need to configure the EFI system for our Bronco. Go to wizard, select our EFI unit, next. This is an eight cylinder and then set it to 302. Target idle, we'll make it 750 for now. We have a stock cam in here. No power adders. We just have a coil. We don't have a CD box, or magnetic, or a dual sync. Stock cam sniper. Now it's going to configure it.

Now were going to check and see if our update saved and there you go, it recognizes that it's a 302 V8 with a stock cam. Now we're going to start it up.

The Holly Sniper EFI System is installed. The Bronco runs and idles great. I started up super easy. Now that you have it running, you can go do some more fine adjustments with this and do some data logging. Installation should take you about a better part of a weekend and before you know it, you'll be heading down the road.