The inner workings of wiring harnesses can be a tangled mystery, and most people in their right mind wouldn't cut one up. Even with all of my dealership and aftermarket electrical experience, I have only opened harnesses a couple times. When it comes to diagnosis, the only information the manufacturer gives you is: diagrams, connector pin-outs, ECM input/output, and voltage/resistance checks. This information is useful and does get you an answer, but now you will be able to see what exactly is happening inside the loom. 

First, I'll tell you why I'm doing this. Since the 2zrVios is now for race use only, I purchased a set of Delphi HES Circular Connectors to create a single wiring connection to the car. Now of course there will still be the large power cables to the alternator and  starter I'll need a junction for but I'm mainly referring to the engine sensors and transmission speed sensor. So lets get started. I like to categorize the harness into 4 parts; 1-Engine sensors, 2-Power supply, 3-Grounds, 4-Main fuse box pass-through. Here is what this harness looks like spread out:

There are many different sensors on engines today, and all of them have a important role in maintaining harmony.  Some priority sensors even have a grounded shielding around their signal wires to protect against EMI. Here I will list all of the sensors and where their wires go:

Crankshaft | *1/*2-ECM * Ground shielding
Camshaft | 1/2/3-ECM
Knock | *1/*2-ECM * Ground shielding 
Cam Advance OCV | 1/2-ECM
Coolant Temp | 1/2-ECM
A/F Ratio AND Rear O2 | 1-12v supply/2-ground/*3/*4-ECM * Ground shielding 
Injectors | 1-12v power supply/2-ECM
Coils | 1-12v power supply/2-ground/3/4-ECM
Evap Purge | 1-12v power supply/2-ECM
Electronic Throttle | *1/*2/3/4/5/6-ECM * Ground shielding
​Voltage Regulator |  1-12v(BATT)/2-12v(IG)/3-A/C AMP/4-Meter
Oil Pressure | 1-Meter

Engines need voltage to run, the same 12 volts you charge your phone with is powering the engine sensors as well. All of the sensors get their power from the engine fuse box, witch is powered directly from the battery. Now of course the power supply system has many fuses in place for redundant safety and circuit protection. So lets look at what individual circuits there are for the engine harness:

Coils/Injectors | AM2 15A
A/F (sensor1)/Rear O2(sensor2)/Purge | EFI 20A
​MAF | EFI2 10A
Voltage Regulator | Batt- ALT-S 7.5A/IG-GAUGE 10A

This is pretty self explanatory. For any solenoid, switch, or sensor to operate properly we need to have a clean ground signal. The entire collection of grounds terminate here at the valve cover, here is all of the ground wires in the harness:

ECM (C19) #2/#4
Coils (C11/12/13/14)
Crankshaft ground shielding 
Knock sensor ground shielding
A/F ratio ground shielding 
Electronic throttle ground shielding 

Ok guys this is the last part, here are the remaining wires passing through the fuse box. Whenever the ECM, Generator, Meter, EVAP system, or ABS systems need to communicate, these are the wires performing those duties:

Rear O2 Sensor
Generator signal to meter
Oil pressure signal to meter
EVAP Canister Pump Module control
Starter Signal
Reverse lights signal
Clutch switch signal
Cruise control switch signal

I believe thats all there is. I hope this explanation helps to show that engine harnesses are just a bunch of wires and not really that complicated. These harnesses are mass-produced to be reliable and easy to check for faults, so the only tool you will ever need to inspect them is a DMM. When it comes to repair that's up to you, some prefer crimping while others suggest soldering. You can also go check Ebay or the salvage yard for a whole replacement. I personally like to have a couple spare harnesses for the extra plugs, and when I need to repair a wire I prefer soldering and a sealing type heat-shrink. Feel free to provide some feedback or ask any questions you may have, and good luck!
​

Most of the racing we do here is autocross, so our car isn't really abused hard enough to warrant any type of special inspection. We usually just do a quick safety check after each autox, and then we do a proper thorough inspection bi-anually. But when it comes to track competition, the stresses on the car are much higher. You're out there pushing the car for five 15-20 minute sessions, accumulating a bunch of race miles on the car and going through a full tank of fuel.

​If you search the internet there are plenty of pre-race checklists, but why not any for post-race? Isn't it better if you catch any issues right away instead of once your in planning mode for your next race?

I like to be proactive instead of reactive, so we've put together a list that should cover every area of the car and has room for you to add your own items. We've also put together a video showing some our post-race inspection practices.

We’re trying something new here on the Blog, if you would like to receive a free copy of the list, sign up to our news letter below and we’ll send you the free print out and new blog posts straight to your inbox!

Back in 2016 shortly after I did the 2zr-fe swap into our Yaris, I sent in a oil sample to be analyzed. I ran the AMSOIL 10W40 for a full 6000 mile interval in my daily driver/weekend autocross swapped Yaris. I did not attend any track racing events during this sample, and I was not using an oil catch can yet. Another thing worth mentioning is that the car still had an automatic transmission, even though I manually shifted it when racing or doing spirited driving. I think that's all of the details so lets take a look at the sample results:

If you look at the comments you'll see they mention the viscosity is slightly low, but aside from that it's a clean sample. I thought it was strange that the Amsoil viscosity didn't hold up in a well maintained Toyota engine, but hey the sample was clean so who cares right? I decided to change my oil every 5000 miles instead and didn't take another sample for a whole year. 

Fast forward to 2017 and Ive decided to run the MOBIL 1 10W40 for the sole purpose of comparing test results. We ran this oil for the entire autocross season and 1 track event with TRD cup...with 2 drivers at every event! The car is no longer a daily driver, it is only driven to races and back. It had a 5 speed manual transmission at this time, and we ran a oil catch can for the whole season. I'm not sure how many miles we put on this oil either, maybe I should log them in the future. Oh well, lets look at the sample:

Here again we have the mention of low viscosity in the comments and this oil was run for a significantly shorter time. Aside from that you can see that the wear and multi-source metals look about the same on both samples: Iron, Aluminum, Molybdenum, and Boron. The differences in additives is because these two companies use their own formulas, so there is no way to say either is better than the other. Contaminants are showing a large increase in sodium, this could mean there is a coolant leak somewhere or that could just be part of the Mobil 1 formula. Since my car has never overheated, I'm not going to worry about this unless the number goes way up next time. 

There are many factors at play here, but one thing remains constant...low viscosity. Since there was no mention of fuel dilution or any other extreme contamination, I feel like both of these oil products may be inaccurate in their viscosity claims. Other than that both oils did their job and protected my engine even under constant load and high cornering forces, so I'd say these products provide the same amount of protection. 

So I ask myself, "how is this possible? Why wasn't the Amsoil much better?" I'm an Amsoil dealer and I'v been using the product for 5 years, I also recommend this product to my friends and family for racing use. I've been through every section of my Amsoil Business page, and read many of the field tests performed by 3rd parties. I was convinced I was using a superior product, and so are many others. 

It may be possible that these samples performed similarly because I have a safe little Toyota, maybe if I had a turbo engine or a high horsepower V8 things would be different. Maybe its because a 6000 mile interval is more stressful to the engine oil than a full year of racing(doubt it). I really have no concrete answer as to the reason these two oils yielded seemingly identical results. Maybe you can share your test results and  comment your thoughts on this below....

2018 is upon us, and with a new year comes new opportunities for partnerships and experiences. Our timeline for this new year will be similar to last year, find a co-driver and attend all possible racing events. We already have a new co-driver lined up and we are very excited to have Patrick join us in the fun, he has plenty of racing experience to help us push the Yaris to new heights. We also plan to hit the ProSolo in Fontana, CA and 2 new racetracks this year; Auto Club Speedway and Streets of Willow.  

As you may already know, we recently completed our C60 6 speed swap into the 2zrVios. The close-ratio nature of this transmission coupled with a 2000lb car provides quite the adrenaline rush, and we can't wait to start the testing. Aside from lots of racing, the only other plans I have for the car this year are:
​
1) Shave off more weight. 
-The car is a ton of fun to drive as is, but we could all use a bit more speed right? I'm not interested in forced induction so I'll try to make the car lighter by removing more metal, sound deadening,  and finally toss the passenger seat.

2) Fit some proper aero to the underside on the car.
-After all of the cones I've hit along the way, you can imagine the condition of my front bumper. Zip-ties and screws hold it together, and there is a large opening under the front of the car where air dams were ripped away. 

3) A little more power.
-I want to finally buy a cold air intake and the light-weight crank pulley then go back to the dyno and see what the gains are. At this time my 2zrfe has only a performance exhaust header, otherwise its stock.
​
4) Prepare to go to a stand-alone EMS. 
-I'm still running the car on and ECM from an automatic Scion xD and all of the original wiring is still in the car for the airbag system and creature comforts. I want to pull all of this extra wiring out and run only the essentials like an EMS, lights,  and wipers. 

I'm excited to get another year of racing in this car, and so glad all of you have stuck around to see how far we've come. I really do feel blessed to have this opportunity and team of amazing people supporting us. What I said to Matt Farah years ago during the one-take is still true to this day "its a work in progress". ​

For anyone interested, I'll link all of the event schedules below:

​San Diego SCCA Solo

​SCCA ProSolo

TRD Cup

​Optima Street Car