Project Miata Update

Check original base tune setting for CLT thermistor setting. So which is it, Mazda or RX-7 S4&S5? So I read some old posts on and Braineack says several times to use RX-7 S4&S5. Every time I go to Tools –> Calibrate Thermistor Tables and set CLT to RX-7 S4&S5 and write it to the controller, when I open it back up again it shows that CLT is set to RX-7_AFM(S5 in AFM). Both Common Sensor Values share the same data tables so I’m thinking this is just a bug in Tuner Studio.   Figure out why MS3 is not […]

Project Miata Update

Figure out why MS3 is not reading NB cam sensor. Could be bad sensor or bad wiring between sensor and CAS harness. So I think I fixed the cam position sensor (CMP) issue: power and ground were apparently swapped by mistake due to misread wiring diagram (sensor pigtail has three black wires so no help there). I Googled pictures of exemplar 1999-2000 Miata engines and zoomed in on the CMP sensor to verify the OEM wire colors.   Apparently when reading wiring diagrams, the view is as though you’re looking at the back of the connector where the wires go […]

Project Miata Update

The plan is to tow the Miata from my dad’s house to my house after Thanksgiving so that instead of hibernating in a cold garage all winter long, it can stay cozy and warm in my garage where I can begin the painstaking process of tuning the ECU as time permits. Our winters are generally much more mild and thus more conducive to working on cars. Also, we have a lot more dyno facilities in my area. The goal is to street tune the car. Then once the car is generally drivable and I better understand the ins and outs […]

CB350 Fuel System Plumbing

I’m using a Pingel Power-Flo On-Off “Race” fuel valve with a 5/16″ outlet. My Mikuni VM30 carbs are designed for a 5.5mm ID fuel supply hose. Given the size mismatch I needed to find a way to step down the hose size from fuel tank outlet to carb inlet. To do this I routed the fuel as follows: From petcock through 5/16 Tygon F-4040-A hose to Jiffy–tite dry break fuel system quick disconnect (-5 AN inlet, -5 AN outlet). From quick disconnect to Pingel 1-in 2-out fuel filter. Conveniently, the fuel filter is 1″ in diameter so I use a stainless steel […]

Tuning Tasks

Check original base tune setting for CLT thermistor setting. I messed around with this when my CLT sensor was stuck at the failsafe value of 180F. Turns out I had a broken wire in a butt splice underneath some heat shrink that I repaired. So which is it, Mazda or RX-7 S4&S5? Figure out why MS3 is not reading NB cam sensor. Could be bad sensor or bad wiring between sensor and CAS harness. According to Reverant, the MS Labs MS3 needs no adjustment to fix this. Maybe it has a circuit that automatically adjusts sensor input sensitivity or gain? Regardless, I’m unsure whether there is a […]

It’s Alive!

Big milestone reached with the Miata project. Still a big mountain to climb ahead as I teach myself how to tune it so that it actually drives under its own power safely and reliably. But it feels good to finally have reached this point. I thunk I was an engineer and now I are one 🙂   1991 Mazda Miata with 2000 BP4W motor swap, TWM / Borla individual throttle bodies and MS Labs Basic MS3 Megasquirt ECU. Starts, idles and revs with no load. This is about as far as a base map will get you. Now the real […]

IAT Sensor Mounting Location

Getting super accurate IAT readings with an ITB setup isn’t so easy without a cold air intake plenum. While a cold air box is ideal, to begin with, I’m running an open element air filter. Accordingly, I must accept that there will be some IAT error no matter where I mount the sensor.   Initially, I mounted my IAT to the shock tower on the exhaust side of the engine bay and some people questioned that decision. I figured it wouldn’t be that big of a deal since the exhaust manifold is getting a thermal insulating blanket from Track Dog Racing. And […]

Project Miata Update

Got another day to work on the car. My dad got the Golden Eagle vacuum manifold mounted and the vacuum connections made. He also made a little bracket to help support the coolant return hard pipe and fit the PCV oil vapor catch can.   We had to redo the throttle cable end so that we could use the TWM supplied cable adjuster. First we cut off the factory adjuster that was swedged onto the cable conduit. Fortunately my tackle box of cable making parts from Flanders came in handy as I needed to fit a cable ferrule over the […]

Project Miata Update

Made some more progress over the weekend. – All new clutch hydraulic system filled and bled – Throttle cable shortened – Vacuum manifold installed on fuse box bracket where windshield washer bottle used to be – Vacuum line for MAP sensor routed through firewall to ECU – Vacuum caps and constant tension spring clamps fit to the hose barbs above each intake runner on the ITBs – Flexible fuel hoses made   ^^ Picture shows the splayed cable ends after soldering. It is the splayed ends that give the cable end strength. The solder just keeps the ends frozen in […]