Hi All,

I bought a PLX R-500 Data Logger / Wideband O2 Sensor Gizmo. My goal is to be able to do real world data logging, and use the A/F information to tune my MTH map. Anyway, I figured I'd share my experiences with the installation. It's pretty indepth, and you have to get over a fear of hacking the wiring harness. I'd give it a 7-8 out of 10 with a 10 being a engine rebuild. That being said, it takes a bunch of time for a first installation. (I could do it much faster now....)

Main Parts....
Head Unit

Wideband

Exhaust Gas Temp Sensor

Misc Cables


Proceed at your own risk! This involves modifying the engin wiring harness at the connector to the ECU. If you aren't good with wiring, or always manage to leave a buch of melted insulation when soldering, DO NOT DO THIS! It takes a light touch with the iron to keep your wires in shape. There is no "30 second" reversal, and forget about hiding it. And if you try and screw up, I'm happy to help, but it's not my fault!

Anyway, there are a bunch of stages. I'll edit this post as I get them all done. Before you do any of these steps, disconnect the battery....

Stage 1: Power Hook up. I used a relay tap (from Radio Shack) and found a relay (seat heater, I think) that was switched.

For a ground, I got lazy. To go behind the fuse panel or to find the ground point, the trim panel needs to be removed. Looks like a pain in the butt.

I don't think this is the right thing to do. The analog inputs are single ended, taking a voltage reference from the power return. So I should take the power and ground from the same place the ECU does, and I haven't figured that out yet.

Stage 2: Analog Signal Inputs. First you have to identify the wiring harness pins. And guess what, my 2002 S doesn't match everything in the Bentley manual. So be prepared to ohm out some stuff, or check my results to see if yours is the same. Anyway, these are the sensor inputs I chose:

Analog Inputs
Knock Sensor.......Yellow.............Pin 8 (there is a knock input for the PLX)
MAP Sensor.........Yellow/White....Pin 29 (not listed in Bentley at all)
Throttle Position...Red................Pin 10
Air Intake Temp...Yellow/Blue......Pin 27 (from the T-Map sensor)
T-Map Pressure....Yellow/Violet....Pin 31

Speed Inputs
RPM Input...........Black..............Pin 54 (I couldn't find it...)
Fuel Injector #1...Brown/Yellow...Pin 21

First I routed the I/O harness to the engine comparment. I took a wire hanger, unbent it, and cut it at a diagonal across the wire so it was sharp. I pushed this through the rubber strain releif that one of the wiring harness bundles uses to go through the firewall. There's lots of space, and more wires could be run here. The view from under hood is pretty restriceted.

It's much more obvious from inside the cabin.

I taped the end of the I/O bundle to the hangar wire, and pulled the I/O bundle through. I then routed it the same way the ECU-Cabin wiring bundle goes into the ECU housing.

The Engine Harness is disconnected from the ECU by pulling a plunger that releases the connector. It's a bit of a pain, as the plunger is under the wires and it's tough to get stubby fingers like mine in there, but pull it back and the connector will lift up DO NOT FORCE THIS CONNECTOR OR IT WILL GET EXPENSIVE FAST!!!!!!!!

Don't be an idiot like I was and try to lift off the connector cover. You might brake something. Cut the wiretie that holds the wire bundle to the connector cover. Pinch the connector cover at the base (near where the wire tie was), and pull back. It will come away, hinged on two prongs at the other end of the connector.

Find the wire you want to tap. My list is above. Isolate the wire from the rest of the bundle, and CAREFULLY strip some of the insulation from the wire. I used a brand new exacto knife blade, didn't drink caffinated coffee, and was very, very carefull. I only whittled away about 150 degrees worth of insulation for 3/16ths to 1/4 of an inch....

Sorry the photo is fuzzy.... Tin the individual wires (that's get solder wicked into each wire separatly before you solder the two together. If you didn't know that, it's a good hint to not do this). I used a soldering iron temp of about 670 F and a fine tip. Since they're tinned, a real light touch is all that is needed to solder them together. Wrap the junction with some electrical tape. This is the finished work for the data logger. I haven't replaced the O2 with the NB output from the PLX (it can emulate the stock NB), nor have I connected any of the outputs.

Now put the connector cover back on, and re-attach the engine harness to the ECU.

Place the ECU cover back on. This is the view of the I/O bundle from under the hood.


NOTE: The PLX uses single sided analog inputs. The Mini knock sensor is on a separate, isolated circuit for noise immunity. I've come up with a circuit to get around this, but haven't built it yet. When I do, the knock will be working, but until then, it reads 0....

Stage 3: Wide-Band Sensor & EGT
I added these with some exhaust work. Here are the two sensors mouted into the exhaust. The EGT needed a boss welded on.

To get the wires run up to where I was going to put them through the firewall was a pain. I removed the airbox base and used a hangar wire to poke down there, taped the wires to the hangar, and pulled them up.

This shows the wire routing.

I took a while to make sure that he wire were wiretied out of the way.....
I ran them though my favorite rubber grommet, this photo is from running the GTech power, but you can see the analog wires for the PLX here as well. With the wideband harness and the Tc wire, it's getting crowded here!

Once I had all the wire on the right side of the firewall, I hooked the whole thing up! Now I have EGTs and A/F ratios....


Stage 4: Mounting the Head Unit
First off, let me say that PLX should have a better mounting scheme than thay provide standard with the unit. What they deliver is "You figure it out!" That said, I wanted it where I could see it, didn't want it too in your face or calling out "steal me", and I didn't want a pain in routing the cables, which are pretty big. Also, every time I take out the dash pad, I'd need to do a lot of wiring just to take it out of the car, so I decided to make a mounting bracket that is fixed to the dash pad, but use earthquake velcro for attaching the head unit to it. That way, I'll be able to run the wires under the dash behind the stock guages, where it won't look like crap. So we're off!

My mounting bracket is a 4"x1"x1/8" Al bar that I bought from Home Depot. I figured out where I wanted it, and marked the bar and the dash pad for drilling. Here's the bar mounted to the pad.

These are the screws from the back.....

I wanted the unit angled a little differently, so I used a bunch of washers as a spacer.

The dash pad can go back in now. This is the finished bracket.

I didn't have any earthquake velcro around, but this is how it will work out. I'' fix the phot, and add the wire routing later. The little girl wasn't happy and cut my work short.....


Stage 5: Computer Software (to be added)

Rev history....
7/20 Added power connection photos.
8/10 Added head unit mounting, less wire routing
8/24 Added sensors

 

If anyone cares.....

 

Looking good doctor

Thanks for sharing :smile:

Henry

 

Someone noticed! Yeah!!!!!

Matt

 

Multiple someones.

Steve

 

I can't wait to hear what you think of it. I can't see myself doing that much custom wiring on my car. Your must braver then I.

 

The biggest hassles are the bungs on the exhaust, and routing through the firewall. The wiring looks hard, but isn't. Also, if there's good CAN based data loggin (faster than OBD-II) then you may not need the I/O signals....

I've found that I need to do some work to get the knock sensor to work, but it's doable.... I'll keep posting as I make progress.

Thanks for the encouragement. The silence was deafaning after the first post.....

Matt

 

The OBX headers are back in stock at sparktec, so one is on the way. I'll get all the bosses mounted to that (I need an extra for the Exhaust Gas Temp). I've found good Magnaflow high cap cats for about $75 with bungs attached....
I don't know if I'll do this before the rest of the 2.5" exhaust is ready to go, so it may be a few weeks till this gets finished up. I'll be mounting the unit before, as I can use the logging now.... But the wideband sensor and the temp probes themselves will take a while longer....

Matt

 

Hmm those OBX headers sound enticing. Although I'm not into doing headers..rather save for an exhaust.

 

I found that I could have a 2.5" single sided exhaust done in aluminized mild steel for less than $200, but it takes some work to gather the parts, and you need a shop that's good at welding. SS costs more... But if you go aftermarket, you're talking over $500! Yikes! That's a lot of money.....

If you go the low cost header and a high cap cat, that will all be less than $300. If I go mild steel for the rest (but I'm leaning to SS), the ENTIRE exhaust system could be had for about $500, with a lot more capacity. Anyway, the OBX looks like a good addition...... I hope!

Matt

 

Any update????

 

All the parts are here but some tubing and a muffler. I'll be talking to my muffler guy after a dentist appointment today. Then it's schedule, cut and weld!

The reason I'm writing about the exhaust upgrade is that the wideband goes in with the header.....

I'll be mounting the display before that happens, and adding some updates for that.

Also, there is an issue on picking up the knock signal. I've almost got that cracked (I think I know what it is, and I've designed a fix. It's half-way done, and then I bench test it....)

Matt

 

I stopped by my buddies exhaust shop. We'll be doing the installation next week, thursday or friday.... Then I'll finish up the standard install. With luck, I'll have my widget working too and I'll be getting A/F, EGT and Knock at 10 Hz!

Matt

 

Next section done....

 

next section done...

 

Thanks for the update. Pics were great. Any more??? Please share the data logging info when you get it.

 

Hey Matt:

Any updates on picking up the knock signal? Were you able to come up w/ a solution to get some knock signal?

thanks

///gilbert

 

The knock input on the PLX is single ended (referenced to the ground of the car). The knock sensor on our car is isolated, and shielded. If you want to do it right, you make an isolated, differential input amplifier to carry the single over to the native ground... A big pain in the butt! I got the isolation amplifier as a sample from TI, I think it's an ISO122 or ISO124. You can get 1 Watt DC/DC converters as samples as well.... I've got all the final parts I just have to put it together.. But I'm getting knock numbers now a different way

Overall, the wideband is very nice, and the EGTs are very nice to know as well. But there are some problems....

1) The display just sucks. If it's not night, forget about seeing it, unless you mount it right in the center of you field of view. Not enough contrast, and too much reflection on the screen.

2) While the data logging is nice and fast, at 10 Hz, you can only log four parameters! There are four analog inputs you can select, the EGT, O2, Knock and the two speed inputs. You get to save just four of these, so choose wisely! For me, this means EGT, O2, RPM and one of the other inputs....

3) The logging is somewhat braindead. If you're logging, it's not displaying any of the real time information. It just shows you the VCR-like logging controls, and a bar to indicate how much memory is left.

4) Did I mention the logging is somewhat braindead? When you selct the logging menu, it checks the entire flash memory before you can say "go" so no fast little captures as the need arizes.

5) And the logging is somewhat braindead. for the analog and speed inputs, it displays raw voltages only, and speeds are measured in Hz! (Not RPM... Grrrrr) No way to change it. So if you're looking at one of the MAP sensors, you better know what boost corresponds to what voltage...

Overall, I'm somewhat dissapointed. Sure, it's got a lot of bells a whistels, but if I were to do it all over again, I think I'd do it another way...
The guys who made this don't really do a very good job on the analog side of the product, the wiring is a major pain in the butt, the connectoization of everything isn't that good (I had to cut a cable and re-wire the connector to go through the firewall).

But at night, it sure looks pretty! And the wide-band has already taught me a lot about how the motor is running (not all of it good). EGTs are interesting to watch...

~550 deg c with a warm motor at idle.
~750 deg C with the foot down a bit, spirited driving.
~900 dec C + when really hammering it near redline!

~950 deg C with spirited driving and a vacuum leak! (was getting a bit lean too).


Matt

 

Wow I guess they didn't really did that well based on your review.. hopefully this will be improved upon with their future firmware revisions..

Anyways, I will be installing the PLX next weekend... Some questions for you.. According to your first post, you were not able to find the RPM wiring, did you ever find it?? So for my installation, all the wiring is what I would need then right?

================
Analog Inputs
Knock Sensor.......Yellow.............Pin 8 (there is a knock input for the PLX)
MAP Sensor.........Yellow/White....Pin 29 (not listed in Bentley at all)
Throttle Position...Red................Pin 10
Air Intake Temp...Yellow/Blue......Pin 27 (from the T-Map sensor)
T-Map Pressure....Yellow/Violet....Pin 31

Speed Inputs
RPM Input...........Black..............Pin 54 (I couldn't find it...)
Fuel Injector #1...Brown/Yellow...Pin 21
================


Wow 950 degree C... did you hear any pinging?? That sure is hot.... By the way, did you install your EGT near the head?? or more downwards?? If it's downwards, the temp will be a little cooler..

Thanks Matt..

///Gilbert

 

Don't bother with the knock sensor until you wire up a circuit. If you just connect the knock input of the PLX to pin 7 of the ECU, you'll but noise on the knock sensor that will confuse the ECU into thinking it's pinging. So leave that one dissconnected until you've got your circuit done (Pin 8 is the knock reference, and I think 43 or so is the shield).

No pinging with the high temps, but I was smart enough to stop hammering it so it would run a little cooler. I spend the weekend hunting vacuum/boost leaks, and I think I found one. Car's almost back together so I should know shortly.

For the speed inputs, I used injector number 1. Interesting feature. To save gas, the ECU shuts off the injectors when you're engine breaking, so the RPMs go to 0! There's a crank postition sensor that will give much "faster" data so it should do better than the 120 RMP resolution of the injector (fires once per two revolutions, with a resoltion of 1 hz, so that's 120 RPM!). I haven't hooked up my second speed signal, sometime I'll play around and see what I can find.

One other note. The wideband draws some current. You may want to have an auxiliary power switch, so you can have the car ON in the driveway, without sucking all the power for the O2 sensor heater.....

Matt

 

sorry to barge in but thx for the Stickers (pod)

 

I've been getting use out of the thing! I did a larger TB upgrade, and instantly ran into some issues... (Don't ask, I'll post completely when I've solved it all....) anyway, I used the device to find what RPM and throttle postions induced a (very) lean condition. Mostly to avoid the situation, and secondly, to know where I have to work on the tune. But I gotta say that seeing 18 AFRs with slight tip in at 3100 RPM is scary, and seeing the EGTs go over 1000! You either hammer it to get the gas in, or take the foot out, and slow down Boo hoo!

I've also started moving data into the software. When I'm better at it, I'll post some screenshots and the like. I'm getting happier with the unit, but I'm still dissapointed in the analog I/O, and really dissapointed that they opted for a slick looking display... That you can't read at all in bright daylight.

Anyway, I'm getting happier, and when the TB issues are closed, you'll all know how I used this (probably poorly) to close some issues....

Matt

 

Thanks for the update.... Were you able to do the firmware upgrade yet?

I finally got a chance to turn my on.. I haven't done any of the speed/analog inputs, but just powered it up.. Daytime, you are definitely correct, it is AWFUL.... hard to see.... Maybe will finish install tomorrow, as soon as I figure out how to splice into the DME wiring..

Did you get a chance to connect your speed # 2 input or are you still tapped into injector #1... BTW, as far as your

RPM Input...........Black..............Pin 54 (I couldn't find it...) <== Transmission RPM Sensor...

I think this only applies to the automatic transmission... From reading the Bentley manual, I couldn't find this talking about the manual transmission, so that is probably why you couldn't find it...

BTW, as far as your analog signals are concerned, how did you calibrate the logger to get the proper reading from your voltage?

Thanks

///Gilbert

 

I'm still in injector #1, and it turns off under engine braking!
I think you're right about the auto trans, it's so the computer can figure out "shifts"..... But the manual is very unclear about it.
And with BiM-COM, I can log raw and processed values to get the map, but I haven't done it yet.... I have to log some data.... if you want to do it in %, the analog signals go from 0.5 to 4.5 volts. Don't know the temp map though...

Matt

 

Hmmmm...... I'm not really sure what happens internally when we do an engine brake, but does it tell the fuel injectors to stop it's duty cycle thus causing your RPM to drop. Also, do you see the RPM go to 0 when going to upper RPMS (6500) due to the fuel injectors shutting down? According to the manual, "ECM selectively deactivates injectors to control maximum engine rpm. When engine speed reaches 6500 rpm, injectors are individually deactivated as required."

I was also thinking of getting my RPM signal from the primary ignition coil.. When I had a turbo Civic, I used to tap in my ignition coil for RPM signal. I wonder if this would be the same for our MINI and if I will see the same results, such as the engine braking effect.

As for the speed sensor, it's too bad there are 4 speed sensors on the MINI. And these 4 sensors tap into the ABS unit before it gets relayed to the DME, unlike other cars where the speed sensor input taps into the DME. I wonder if there is an easier way to get the speed signal?

As far as calibration for the analog signals, I would just have to wait for your computation, since I don't have any other data loggers.

Thanks

///Gilbert