Our tech guys will get out here when they catch up with Monday email madness, but I can help get you started in the right direction.
All of the basic stuff, power, ground, injectors, CLT, IAT, O2, and TPS sensors, are the same as any other engine in the world. The MegaManual covers this stuff in detail so I won't rehash it.
Your stumbling block is that ignition pickup. It's a Toyota ESA style system from what I can dig up. From what I can find the EP82 and EP91 cars are both single coil distributor based ignition systems. I'll need someone to confirm, but I strongly suspect you've got a CAS in the base of that distributor with two wheels inside of it, and three VR sensors. The Primary wheel has 24 teeth and a single sensor. The Secondary wheel has 1 tooth, but has two sensors that read the wheel, 180* opposed from each other.
We decode this ignition system with no problem, if we can read the signals clearly. And that has always been the biggest trouble. To understand why you have to look at the design of that CAS, and it really boils down to all three of those VR sensors share a common ground. That causes noise on ALL of the sensor outputs any time ANY of the sensors read a signal. The noise can be filtered, and obviously the Toyota OEM ECU did a good job at that, and more recently we've put some work into isolating this troublesome ignition pickup and filtering this noise as well allowing us to read it clearly. Note this is the same type of pickup used on countless other Toyota's and Mazda's. And a very similar system is used on Honda's as well.
To read this clearly with a standard MegaSquirt EMS (MS1 or MS2 based on a PCB v2.2, v3.0, or v3.57 board) I highly recommend the
Zeal Daughterboard, this is a dual VR Conditioner board that was specifically designed to solve this issue with these ignition systems. It was designed and tested on RX7's which have been notoriously problematic and use the same CAS. Solves the problem every time. It's been tested on other similar vehicles too now and should work well on your EP's.
The DIYPNP on the other hand does not need the Zeal Daughterboard, this is a new product that was designed with these troublesome ignition systems in mind and we so far haven't had a problem with any vehicle that required additional conditioning.
So-- that said.
NE+ is your primary tach input. Goes to pin 24.
G1+ is your secondary tach input. Goes to wherever you've jumpered on your MS to bring that in.
Ground these sensors (G- VR Sensor Ground) at the ECU.
Jerry a.k.a. 'FoundSoul'
http://DIYAutoTune.com
