Installation of your Holley Sniper kit

Installation of your Holley Sniper to your VW is fairly easy, just follow these tips. This is assuming you have also purchased the appropriate fuel system from Holley which also includes all the fuel line, clamps, pumps, etc

The throttle boy comes ready to bolt on, just install the two 90 degree black anodize fuel fittings first, on the return line that comes off the backside, install hose and proper clamp. After the throttle body is mounted to the intake manifold, the return line is pretty much right against the fan shroud so it is much easier to install this line prior. 

The fuel pump should be mounted below the fuel tank, as close as possible. In a Type 1 the ideal location is under the tank, opposite the brake master cylinder. On a transporter they mount easily (an accessible) in the engine bay on the driver side next to the battery. You can also mount the pump underneath as well if you are going for a cleaner engine bay. On single and double cabs we install them on the frame rail right below the fuel tank. Don’t worry about length of fuel line after the pump, it will easily push the fuel needed as long as you don’t have any kinks in the lines. The fuel pressure regulator is locate in the throttle body so maintaining proper pressure due to fuel line length is no issue. 

For the fuel lines at the tank, your kit includes a stainless steel 6AN bung to weld into the tank. For the return, and an adapter from CB Performance that will thread right onto the stock fuel outlet of your tank. The return line should be welded to the bottom of the tank. Don’t weld the return to the top of the tank unless you also incorporate a drop tube to the bottom of the tank. This will keep fuel aeration at a minimum. On a Type 1 we have found the channel on either side of the pan where the body bolts to it is an excellent place to run the fuel lines. It keeps them above the bottom of the car, an on the exterior of the interior cabin. 

The throttle cable included is the universal cable from CB Performance. Each end of the cable is different depending on your throttle pedal connection. To cut the cable we have found it best to use a torch to burn it off at the length you need. Cutting it otherwise can leave a frayed cable that can be difficult to work with. The torched off end is clean, and won’t fray. We use a simple oxy/acetylene torch here. One end of the black cable will slide over the stock tube at the chassis tunnel, the other end is threaded with two jamb nuts to fit the small aluminum bracket that will attach to the shroud. We prefer to install the bracket to the shroud with a nut-sert (M6 ideally so your hardware matches, but it is a ¼” hole so the most common ¼” nut-sert will work.) A good sheet metal screw will also work, but over time it will probably come loose. Install the cable bracket so that the cable pulls as directly from the side as possible. Depending on where your ignition coil is mounted you’ll have to play with location to make sure the cable can operate without contact with any wires. You have adjustment at both the cable sheath, and at the ball-link end that attaches to the throttle body. Thread both of these to their halfway point and cut the cable appropriately. This way you have two points of adjustment if needed to shorten or lengthen as needed to get it adjusted correctly. Included in your kit is a chrome plug to fill the old accelerator cable hole in the shroud. 

Temperature sensor is a standard GM ⅜” NPT coolant sensor. Our preferred location is in the cooling tin on the left, so the air from the cylinders and ideally more, from the cylinder head. An 11/16” hole will fit the sensor perfectly, your adapter kit comes with a brass NPT jam nut that will hold it down in the engine tin. A stepped “uni-bit” works great for this hole. This temperature reading is ONLY for the ECU to provide proper warmup enrichment, idle targets, and startup settings. Do not use this temperature as any means for your engine's operating temperature. If you like, the Dub Shop (Dubshop.net) makes a temperature sensor that will plug right in and allow you to bolt the temperature sensor anywhere you like that is more visually pleasing. 

The throttle cable return spring that the adapter kit includes uses the stock ball joint on the original throttle arm and pulls down to the distributor clamp nut. A small eyelet adapter to fit over the case stud will allow you to run one end of the spring through that. 

We also include a 12 foot wiring harness extension. This is long enough to put the display on the dash of a Type 2 installation. Type 1’s just loop up the excess as needed. 

The oxygen sensor bung needs to be welded in. The Holley kit comes with a universal adapter for “bolting” an oxygen sensor onto an exhaust pipe, but the diameter is too large to work properly. We include a weld in sensor bung with the kit. Try to get at least 12” from the cylinder head. Some after market exhaust may already have an oxygen sensor bung installed. If not, this will need to be welded in. Make sure you locate it where you will have room for the sensor to install without interference. 

On the throttle body itself, with the modifications we do you do not need to “adjust” the idle screw. We loc-tite it in position so it won’t move. The idle air control (IAC) will control the idle speed and changes based on temperature of the engine (coolant sensor). Ignore the instructions in the Holley install manual on adjusting this screw as our modifications make it null and void. Adjusting this screw will affect how your engine behaves with a vacuum advance distributor and will not idle correctly if changed. 

All other installation instructions from Holley are in their manual. Follow them thoroughly to ensure a proper installation and operation.

Once you have everything ready and installed, remove the blue power wire from the fuel pump and jump power to run the pump without running the system. It will make a funny little noise as it pushes the air past the pressure regulator. Use this time to check for fuel leaks in the system. If everything is good, re-connect the blue wire to the fuel pump. On first fire-up with a cold engine, turn the key on and wait two seconds (one Mississippi, two Mississippi). This primes the fuel system but also gives the throttle boy a priming pulse of fuel down the intake. Do not touch the gas pedal. Turn the key an the engine will fire up. We have programmed it to idle high at startup momentarily an come down. This makes sure it fires up nice and clean, and also kick the alternator/generator light off in most all cases. Do not have your foot on the gas pedal when you turn the key on. Each time the key is turned on, the position the throttle is at will be programmed as 0% throttle. Having your foot on the throttle will alter proper acceleration enrichment, idle coast-down, etc. If you do accidentally have the pedal down when you turn the key on, simply turn the key off, foot of the gas, an key on again. No big deal. 

The Holley also has a flood clear. If for some reason you flood the engine (key on and off too many times without starting, ignition dies an you crank for a while without any spark, etc), you can hold the throttle over 70% while cranking (after turning the key on without any throttle) and that will give it a “flood clear”, allowing you to crank the engine without any fuel being injected. Once it coughs to life, let off the throttle and it will idle again like normal. 

If you experience the touch screen behaving odd, or it is running poorly, you may be experiencing RFI. This is caused by the high energy ignition leads false triggering and confusing the power and signal wires to the ECU. If you encounter this, first make sure the pink and yellow wire from the ignition coil to the ECU are not touching or running right along (zip tied, etc) the ignition wires. If this is not it, sometimes you need to shield the wires. The cheapest and easiest way we’ve accomplished this is to get some aluminum foil tape (check the HVAC section of your local hardware store), cut it into strips and wrap each of those wires. Follow it up with some wire loom to make it look good. Also make sure you are running resistor plugs. Non-resistor plugs can and will cause RFI issues and result in poor running. 

Now that it’s up and running, what do some of these numbers mean on the display? First thing is, the ECU will not do any fuel learning or adjustment until it is up to temperature. Once up to temp, you’ll see on one of the multi screens a “CloseLp” on the left and a “Learning” on the right, both having a percentage number above them. We have loaded up a learning target table to your unit that works well with most VW’s. Additional tweaking can be done, but we recommend it be done with a laptop as the basic adjustments in the hand held can really mess things up if you don’t know what they’re doing an what else they may control in the system. You have a basic fuel map from the beginning. Once warmed up the system will instantly start tuning itself to the target air/fuel ratios for the part of the fuel map it is in. It has two styles of learning that it tunes itself by. “CloseLp” is the instantaneous tuning. This will hit the target on the fly. But this is not changing the actual fuel map of the software. That is where the “Learning” comes in. Learning builds a table that in a sense, overlays the existing fuel table. This is a much slower learning table as to tune itself more based on averages. The fuel map is based on manifold pressure vs rpm. So for example, lets say you are running steadily at 3000 rpm with a throttle position that held it steady at 67kpa of manifold pressure and didn’t change (not realistic in the real world, so don’t worry if nothing stays constant, it will always be changing where it is on the fuel map). If the CloseLp showed -10%, the Learning would at first show 0%. The more time you spend in this specific cell of the fuel map, the CL percentage will start to transfer over to the Learn map. Eventually CL would say 0% an Learn would be -10%. Anything under 10% on the learn table is fairly close, under 5% would be considered tuned. But that’s only in that cell. The fuel map is a 31x31 map giving you a total of 961 possible cells it could be driving in. In all reality, you’ll only be using cells somewhat diagonally from the bottom left to the upper right. The other two extreme corners of the map will likely never really get driven in. 

As your Learn percentage gets larger, if you see numbers well into the double digits on “Learn” you can go into the display and transfer all tables to the base map and basically re-set the learn table to zero. This is a good way to watch when the tuning is getting close. If you get to the point that you no longer have to transfer the table because all values are usually below 5%, you are good to go. I prefer to transfer to base whenever I see learn percentages over 20% on a new install. This could be daily, but with more driving it quickly becomes much longer between until you are transferring the learn table to the base tabel to get learn percentages below 10%. On that note, there is no harm in letting it run the way it is and letting the learn table have large percentages. It’s just easier to see how close the tune is to the target this way. It will run no different.