Ok I installed my Plx-300 the other day and I thought you guys would like to see the install. I wanted to mount it somewhere visible while driving, somewhere close to the tach. The unit is fairly large (almost 6" long) so finding a place was a little difficult. Anyway I found the perfect place, right next to my boost gauge on the steering column.


I remember reading that the stock narrowband output from the oem O2 sensor is better to use than the simulated narrowband output from the plx wideband. So I decided to keep the stock O2 sensor, this also means that I don't have to mess around with wiring in resistors. Besides, I already have two o2 bungs welded in the downpipe.

1) There are 4 wires + the wideband harness that comes off the back of the plx display unit. Since I'm mounting it on the steering column, the wires will be partly visible. To clean up the install, I used a large piece of black heat shrink.



2) I didn't want to completely hard wire the wideband in case I ever wanted to take it out and use it on another vehicle. So I bought a cheap $5 4-pin connector to connect the power, ground, and signal wires.





3) I got the power and ground source right from the ECU harness.
Power A25
Ground A23
Signal D14


Now you have some options here depending on what you want to do. Here are some scenarios:

1) Remove stock o2 completely, use narrow band output from wideband. No datalogging.

If this is you, you will need to connect the grey wire from the plx display box to pin D14 in the ECU harness. You will also need to wire in resistors across the two black wires in the stock O2 sensor harness. I can't remember the resistance needed, but it goes into detail on the plx website. (also tells you in the instructions that come with the wideband)

2) Keep stock o2, no datalogging.

This works if you have two bungs in your downpipe, doing it this way makes the install really easy. You don't have to touch pin D14 at all, or even wire in resistors. Just supply power and ground to the unit, that's it.

3) Remove stock o2 completely, datalogging.

Now, if you want to datalog a/f using something like hondata, the ECU needs a wideband signal. However, if you are familiar with tuning you will know that when you finish the tune, you would want to leave the car in closed loop and in order for this to work, the signal has to be narrowband. To over come this, you need a way to switch between narrowband input and wideband input. One way to do this is to wire a switch between pin D14, and the white and grey wires from the plx display box.

4) Keep stock o2, datalogging.

This is the method I chose. It's basically the same as the one above, but my switch is connected to pin D14, the white wire from the plx unit, and the stock narrowband wire from the stock O2 sensor (which is also white). The grey wire from the plx unit is left unhooked.



I decided to test my luck and go without the capacitor that is supplied with the plx unit, I will probably end up putting it in eventually.

Here are some pictures of the finished install, I apologize for the small pics, photobucket sucks. If I fucked up somewhere in the writeup or if you have a better way of hooking this thing up, post it up

 

good write-up.

 

 

what about that fat o2 plug? how did you get that through the firewall? lol

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by undercoverdc2 &raquo;</TD></TR><TR><TD CLASS="quote">what about that fat o2 plug? how did you get that through the firewall? lol</TD></TR></TABLE>

There's a grommet sort of below the intake mani to the right a little, this is on my DA, not sure if its there on other cars. The hole is plenty big enough

 

Thats right about where I mounted mine on the ol EM1. Its right in your face, and you just can't help but look at it.

My only problem is when the sun hits it... it just washes out...

 

Up for new viewers

 

Great write-up.

will keep this post for when my plx comes in.

thanks!

 

Nice write up.

I ended up cutting a rectangular piece out of the gauge bezel so that the wires could slide down without putting as much stress on the wire-&gt;display connection.

 

i ran my plx FATTY connector through the firewall by the ecu (where pretty much all the wires run...underneath the battery box)

 

Good write up, will use when I get to that point in my setup.

 

There are a couple ways you could do it...I have no cruise control so it fit perectly where the cruise cable went through the firewall...simple...second option cut the wires and resolder them if you have to.

 

nice.

 

do you know if you can ouput the wideband signal from this to like a apexi turbo timer (which has a configurable afr reading) which wire carries the wideband signal?

 

Not sure.. but

white = wideband output