Boost gauges come in many different sizes, shapes and with many different available features. Many of these boost gauges can read vacuum should they need it, but whatever gauge that you select you must make sure it’s readable in PSI if you are not comfortable with a metric gauge.
We are installing an Autometer boost gauge into a second generation 1995-1999 Mitsubishi Eclipse GSX Turbo, but your install will be very similar if you do not own this vehicle in question. After reading through this article you will know How To Install a Boost Gauge in any turbocharged vehicle.
When you own a turbocharged vehicle, a boost gauge is one of the most important gauges you will ever install on your vehicle. An accurate reading of how much boost you are pushing into your motor allows you to monitor the level of boost your engine is built to handle, and allows you to tune accordingly.
Before modifying your vehicle, you must have this information and it must be accurate to prevent and catastrophic failures or problems.
Tools you will need to complete this job.
- Boost Gauge of your choice
- Wire Cutters / splicers
- Electrical Tape
- Coat Hanger
- 2-3 feet of vacuum hose
- Xacto knife
- 10mm socket
Sensor Install
Tee or splice into an existing vacuum gauge, preferably the one that leads to your fuel pressure regulator ( FPR ) but failing that make sure you tee into a port that is past the throttle body.
If you are installing a mechanical gauge as we are today, there is no “sensor” per se that you will be installing. Instead you will be teeing a nylon line into the vacuum port in question. If you are installing an electric gauge, a remote sensor will most likely take the place of this nylon line.
Make sure to mount the pressure sensor somewhere in the engine bay and away from heat for accurate readings. This is a crucial step in the How To Install a Boost Gauge guide, if this line leaks you will get a wrong reading.
Cut into this line and use the supplied three way tee to splice into the vacuum line and tee your boost gauge line into.
Run this nylon hose into the car by sliding it down near the steering column boot on the driver side of the firewall. Using your XACTO knife, make a small incision that will allow you to pass the nylon line through the hole and into your pedal assembly in the car. Take extreme caution when running this hose, as kinking it or having it near the pedals, pedal arms, steering column or panels may cause a rupture or kink in the line.
Connect the nylon line to your boost gauge, or if you have an electronic boost gauge connect the wiring harness to the boost or pressure solenoid and run the electrical connector into the cabin as you would have the nylon line. Now we’ll move onto the wiring part of How To Install a Boost Gauge.
Wiring
Remove your lower cover by taking off the 4 10mm bolts that connect the lower dash to the metal support beams under the steering column.
After you have all 4 removed, there is just one more bolt behind this panel here. Access this bolt by popping off the panel with a spatula or small knife.
Now with the lower cover removed, you can access your steering column and center column cover which is held on by 3 phillips screws. Once your center cover is off, locate your turbo timer harness or ignition harness.
Red Wire- Constant power 12v – Use your stripper to carefully strip away a section of insulation for this wire, and tee your boost gauge’s constant power to this wire.
If you do not have a turbo timer, use a test light and probe for power with the ignition off.
Orange is 12v Switched power and should connect to the green or blue wire on your turbo timer harness. This wire will be blue if you are teeing off the ignition column. The cigarette lighter is a good place to get switched power also, which is connected by a black wire in the middle of the cigarette lighter.
White Wire – Illumination for lights. This white wire usually is clumped in with the orange ( switched power source ) but for those who truly want to tee the illumination light in correctly which will preserve the dimmer function, you must connect this wire to the tail light circuits.
To tee into the tail lights, the wire harness that runs along the rocker panel and under the carpet on the driver side will have this wire ( green with black dots )
Carefully slit the loom cover to expose the wires. The tail light wire is green with a white stripe, with dashes on it.
Remember that the green wire has white dashes in it, not a solid white as that is the main control and will keep your taillights constantly illuminated.
Finishing up
Use zip ties to secure the vacuum hose or boost sending unit if you own a electronic gauge. Connect the power and illumination wires to your gauge and you are ready to rock and roll!
Happy Boosting!