Tachometer Wiring (Digital)

With all the tachometers available on the market and various price differences between them, it’s hard to know which one to choose. Which one can handle your application? Which one has a memory recall? There is also the debate of digital versus analog. Today, I am going to explain the ins and outs of the Viper Pipes Acewell 1100 Digital Tachometer and data system, part #960-11000, and show you the best way to install it.

This tachometer has multiple functions. Aside from the digital tachometer displayed in the center, it has an RPM bar graph along the left side and top left corner of the display, a digital water temperature readout in the top right corner, and a fuel level bar graph in the lower right corner. You can also switch through the displays to show run time, max RPM, a clock, and battery voltage. The RPM bar graph can be set to either 10,000 or 20,000 max RPM.

The display is also LED backlit and orange in color. The unit has two red LED flashing warning lights integrated into the housing. There is one in the upper right and one in the upper left hand corner. The upper right corner is used as your water temp warning light, which the temp can be set by the user. The upper left corner is used as your shift light.

The tachometer pickup has 4 different settings; 0.5, 1.0, 2.0, and 3.0. This number refers to the number of engine rotations per signal received by the tachometer. For example, if you have a Small Block Chevy V8, you would want to wire the tach lead to a distributor plug wire, then set the tachometer setting to 2.0. This would mean that every time that plug fires, the tach would record 2 revolutions of the crank. This tach can be used with just about any two or four stroke engines, from single cylinder ATV’s and motorcycles, to V8’s.

Once the unit is mounted, it is time to tackle the wiring. The tachometer comes with a wiring schematic included in the box. Each wire on the diagram is labeled with the corresponding color. They have separated the pigtail out into three parts; the water temp sensor plug, the tachometer lead, and the power/fuel level/clock plug. The water temp sensor plug is all wired in and is simply a plug-and-play type installation. The sensor has 1/8” NPT threads, but can be adapted to almost any thread with the use of a bushing. I installed this tachometer into my micro sprint, which utilizes 12mm-1.5 threads in the cylinder head. I use Auto Meter 2277 Temperature Sender Adapter Fitting, 1/8 NPT-M12x1.5 adapter, part #182-2277, to thread into my head. I then installed the sensor into the adapter.

The tach lead wire is a tricky one. In most applications you can wire it into the coil wire or into a distributor/magneto wire to attain a good signal to the tach. However, in micro sprint applications, I have found that it works best if wired directly into your engine’s ECU. If you are using an aftermarket ECU such as a Performance Electronics PE3-IG, as I am, it will have a dedicated tach wire.

At this point, a simple butt splice and some solder for good measure will do the trick. If you are using a stock ECU with a cut down wiring harness, then you will need to look up which wire port on which plug would be the tachometer output, then wire the tachometer lead from the tach to that specific port. If this isn’t possible, you would then have to wire the tach lead into a coil wire on the engine.

We have found there can be some electrical interference when doing this on a micro sprint and that installing the included resistor does help. Be sure to solder any connections to the coil wires. It helps maintain a solid connection, especially with smaller gauge wires.

Now that you’ve got the temp sensor and tach lead installed, it’s time to move on to the power/fuel level/clock plug. Included in the box is a 4-wire pigtail to plug into the tachometer’s existing plug. First thing’s first, are you using a fuel sending unit? If not, you can skip this wire, cut it back, or coil it up and move it out of the way. If you are, then you would want to connect the fuel gauge wire on the pigtail to the negative side of your fuel level gauge in your tank. These would then be connected to the ground on your battery. In addition, the black wire on the pigtail is the ground wire, and would also need to be connected to the negative terminal on the battery.

Next, you will need to connect the brown clock power wire to the positive terminal on the battery. This allows the tach’s clock to run off the battery when the ignition switch is off and not use up the tachometer’s internal battery. The amp draw is so minimal that there is no worry of draining the battery if you don’t race for a couple months.

I have even seen mine go three months from the time of install, to the first race, with no battery drain. The last wire you need to hook up is the red ignition switch wire. You will need to run this wire from the pigtail to the ignition switch. In most cases, you may already have a wire coming from your battery to the ignition switch to supply power to the switch. If not, that can be done at this point.

All that’s left to do now is start your engine and cycle to which display you want to view. The clock is the default display, however, you can view any display while the ignition switch is on. To view the peak RPM’s reached you can cycle through the different displays using the “Mode” button. Once you reach the max RPM display, you can hold down the “Reset” button for two seconds and it will reset the max RPM to 0 if the engine is not running. You can also reset the max water temp display and the maintenance time display in the same way. This completes the wiring and installation of your new Viper Pipes Acewell 1100 Digital Tachometer.