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Sat Nav Conversion Part 2: Performance Gauges "How To"
BEFORE WORKING ON ANY ELECTRICAL COMPONENTS, DISCONNECT THE BATTERY. Open both doors to allow the side windows to drop. Ensure that the doors remain open until after the battery has been disconnected. Disconnect the battery ground cable.
Displaying Engine Performance Data
To display engine performance data, I bought a PLX Devices Kiwi 2 WiFi OBD-II reader. Note that this is an older model of the Kiwi device, pre-dating the Kiwi 2+ and Kiwi 3. The reason for this is that only the Kiwi 2 accepts an iMFD adapter, which is required in order to receive data on oil pressure and supercharger boost.
The Kiwi 2 plugs into the car’s OBD-II port (below the hood release) and transmits data via WiFi to iPhones. (PLX has a Bluetooth version of the Kiwi 2 for Android phones.) Because I wanted to display the data on gauges that were similar in appearance to the car’s speedometer and tachometer, I created a custom 5-gauge “dashboard” using free Windows-based “DashXL” software available on the Palmer Performance (makers of DashCommand) website. I then downloaded this dashboard and installed it on the DashCommand app on my iPhone. (It is saved as “Jaguar XKR 5-Gauge” and may be downloaded by anyone.)
Kiwi 2 with iMFD Attachment, connected to PLX sensor module
Because the Jaguar’s OBD system does not provide data on oil pressure or supercharger boost, I had to install sensors to obtain this information. These data are then sent to PLX sensor modules, which are connected via a cable to an iMFD Attachment that plugs into the Kiwi 2. The Kiwi 2 then transmits the oil pressure and boost data, along with the other data from the OBD system, to the iPhone via WiFi.
The PLX sensor modules are made of extruded aluminum and are the same size: 2 x 2.875 x 1.125” (52 x 75 x 28mm) L x W x H. Each has a “slot” along the top sides that accepts a “ridge” on the bottom sides, so that (with some effort – it’s a tight fit) the modules can be slid together to form a single unit as shown in the photo below. I placed the modules in the passenger’s side engine control module (ECM) enclosure, just forward of the ECM.
In the photo, the two modules are “daisy chained” together, with the FLUID PRESSURE module at the end of the chain. A short cable with two right-angle stereo mini-plugs sends the FLUID PRESSURE module’s data from its output (“TX”) jack to the VAC/BOOST module’s input (“RX”) jack. The VAC/BOOST module then sends data from both modules to the iMFD Adapter inside the passenger compartment via a cable plugged into its TX jack. The photo also shows that, on the left side, each module has its own 12-15V power source; on the right side, a 1/8” rubber hose is connected to the VAC/BOOST module and two black wires are attached to the FLUID PRESSURE module using Molex connectors.
Two modules in ECM enclosure
Oil Pressure Sensor
I highly recommend conducting this part of the installation at the same time you perform an oil change, while the oil pan is empty.
The PLX Devices Fluid Pressure Sensor Module kit includes an oil pressure sensor, 16 feet of connecting wire, a ring terminal, and Molex connector terminals. The oil pressure sensor probe screws into a standard 1/8 NPT tap. Because the XK100 model Jaguars have a non-standard M10 x 1.25 fitting, I used one of TheJagWrangler’s oil pressure T-adapters to accommodate the 1/8 NPT fitting.
I followed TheJagWrangler’s instructions for installing the adapter. Next, I cut the 16-foot length of wire into two equal eight-foot lengths. To be able to distinguish one from the other, I recommend taking some nail polish and coloring both ends of one of the wires. I then cut the ¼” Techflex braided expandable sleeving to about six feet long and threaded the pair of wires through it. Finally, I wrapped some electrical tape around the ends of the sleeving to keep it from fraying, while still leaving about a foot of wire exposed on each end.
I threaded the 1/8 NPT female locknut onto the 1/8 NPT fitting on the oil pressure sensor. Next, I crimped the supplied ring terminal onto the end of one of the wires and slipped it onto the 1/8 NPT fitting. I then screwed the oil pressure sensor into the 1/8 NPT tap on the oil pressure T-adapter until it was finger tight. Finally, I tightened the ring terminal against the T-adapter. On the opposite end of the oil pressure sensor, I connected the second wire to the port labeled “G”.
I maneuvered the sleeving containing the two wires from the oil pressure sensor to the PLX FLUID PRESSURE module as described in TheJagWrangler’s instructions for installing his oil pressure gauge. I used plastic zip ties to ensure that it would stay securely in place. When the wires reached the sensor module, I used a Molex crimping tool to attach a Molex connector to each of the two wires. I plugged the wire that is connected to the port labeled “G” into the TOP of the white plastic box labeled “1” and plugged the wire that is connected to the ring terminal into the BOTTOM of the same white plastic box.
Boost Sensor
The boost sensor was much easier to install than the oil pressure sensor. It did require purchasing some parts that were not included with the kit, however: 1/8” vacuum hose (AJ83877), plastic T-connector (C15644), and a rubber grommet with an interior diameter just wide enough to allow the vacuum hose to pass through.
I drilled a hole in the side of the ECM enclosure large enough to accommodate the rubber grommet. I pushed one end of the vacuum hose through the grommet, pressed it onto the VAC/BOOST module input, and threaded a small cable tie around it, pulling it tight. I maneuvered the other end of the hose under the air intake tube and attached it to the engine wiring harness using zip ties. I then replaced the straight piece of plastic that connected two segments of the existing vacuum hose with the T-connector and pressed the end of the new vacuum hose onto the perpendicular part of the “T”.
Vacuum hose route from ECM enclosure
Vacuum hose attached to T-connector
Final Connections to Sensor Modules
Each sensor module needs its own 12-15V ignition switched power source. In addition, the output (“TX”) jack of the VAC/BOOST sensor module needs to be connected to the input jack of the iMFD Adapter attached to the Kiwi 2 WiFi.
I found an ignition switched power source at Fuse 14 in the Engine Compartment Fuse Box on the driver’s side and tapped into it using a 15A piggy-back blade fuse holder. I ran a wire from the fuse holder, under the black plastic cowl plenum below the windshield, to the positive (red wire) connections of the modules’ power plugs. I ran a ground wire from the negative (black) connections to a screw attached to the car’s body.
Finally, I ran a 10-foot stereo cable with a right angle male mini-plug on one end and a straight male mini-plug on the other from the TX jack of the VAC/BOOST sensor module, back across the firewall (under the black plastic cowl plenum). I then made a hole in the accordion black rubber boot near the brake master cylinder and pushed the straight mini-plug into the passenger compartment, according to the directions supplied by TheJagWrangler for installing his oil pressure gauge.
Buttoning Up the Installation
To ensure that I would not get tangled in wires hanging above my legs, I cleaned up the installation using zip ties, as shown in the photographs.
The first photo shows the Kiwi 2’s OBD II connector plugged into the car’s OBD II port. There is enough slack in the wire to allow use of the hood release.
The second photo shows the thick black wire from the OBD II plug to the Kiwi 2, and the thinner black wire from the iMFD Adapter (right-hand side of Kiwi 2) running back into the engine compartment, secured by several zip ties. The Kiwi 2 unit itself is held securely in position by two zip ties. I positioned the Kiwi 2 where I did because this is the easiest place for me to reach the “wake up” button on the right-hand side of the device. (It automatically “goes to sleep” to save power when the car is turned off.)
Testing the System
Re-connect the battery grounding cable.
Turn the ignition switch to Position 2, turn on the dashboard video screen, plug the lightning connector into the iPhone and turn it on. Press the “wake up” button on the right-hand side of the Kiwi 2. Go to “Settings” on the iPhone, select “WiFi” and then “PLX Kiwi 2”. (If you don’t see it right away, turn off “WiFi” and turn it on again.)
When the iPhone is connected to PLX Kiwi 2, turn on the car and select the “home” button. Choose the DashCmd (Dash Command) app. It should be trying to connect to the phone. Once it does, choose “Dashboard” in the upper-left corner. You should see the screen with four gauges and the clock.
04-30-2018, 12:48 AM
Sat Nav Conversion Part 2: Performance Gauges "How To"
