Hey guys, just got my defi racer boost gauge in today and the directions say to hookup the vacuum hose to the defi sensor and then to a t-junction which connects to the surge tank. Seems like all of the how to boost gauge sites base their how to on the basis that you are using a vacuum hose all the way to the gauge and so they hook it up at the UIM nipple and run it back to the gauge.

My question is.. Do I do the same with my defi sensor? i.e. Run the vacuum hose from the UIM nipple directly to the sensor or do I use the t-junction and splice into the vacuum hose that runs into the mazda boost sensor from the TB?

Any help would be greatly appreciated, thanks.

 

For a boost gauge, use the extra vacuum nipple on the upper intake manifold. It will give true and proper readings. I don't recommend T-ing into the stock boost sensor vacuum line - that is a VERY critical line, and if that T fails or a line pops off, that could cause engine damage.

Check the FAQ, there's plenty on installing boost gauges.

Dale

 

Thanks Dale.

 

+1 to what dale said. I have the same gauge as you and I hooked it up to the extra nipple on the UIM. Gives a very accurate reading.

 

Okay, I'm ready to start hooking up the power wires for the gauges and would like to know where would be a good location. I've searched threads and found that the ash tray light is not a good wire to use a constant +12v wire. Apparently, the large blue molex connectors under the steering wheel are better for this.

So, thats 1 wire out of the way, but I still have 2 more to go...

12v Battery wire (red) ==> 1st gauge to molex (1) and 2nd gauge to molex (2)
12v Ignition On (orange) ==> help please
12v Illumination (white) ==> help please
Ground ==> I got this one =)

I've also looked at the wiring schematics from the repair manual, but that isn't really helping me so any help would be greatly appreciated.