Convert your A engine to EFI.
Contents |
Manifold and Injector
Rather than fabricate a custom manifold, use the stock one that's already on your A12! The photo here show the intake unbolted from the exhaust, but you can do it while it's still together.
Parts needed:
- Stock A12 intake manifold
- #Throttle Body (40mm) from a Hyundai Excel/Accent X3 SOHC
- #Fuel pressure regulator from a circa 1997 Misubishi Lancer
- 3-5mm thick alloy plate for the adapter
- Fuel Injector (500cc)
Mounting the injector, fuel rail and fuel pressure regulator
Throttle Body
The X3 Excel Throttle Body is dime-a-dozen and easy to adapt. The 1995-1999 Hyundai Excel X3 (Accent in USA) SOHC engine is the source. Don't forget to get the wiring harness connectors and a couple of inches of wiring for the attached TPS.
From the wreckers, get the throttle body with TPS attached.
New TPS is as inexpensive as $22 rockauto.com. New Throttle Body (mixing body) is $183 from Hyundai, so buy a used one for $30 or so at the wreckers.
Hyundai X3 (Accent/Excel/Verna)
Fuel Pressure Regulator
Fuel Pressure regulator from a 1997-2001 Misubishi Lancer 1.5 engine, $15 used
Search $35 RockAuto.com 51 psi BECK/ARNLEY 1580463 {#MD311979) STANDARD MOTOR PRODUCTS PR247 AIRTEX / WELLS 5G1265 Denso MD 311979
Mitsubishi Lancer/Colt/Mirage 1997-2001
Sensors
With MegaSquirt you won't need the Datsun airflow meter. Instead, Megasquirt will calculate the air mass using a MAP sensor and and IAT sensor.
- MAP sensor is built into Megasquirt. Connect vacuum hose to manifold
- Obtain GM IAT sensor from a Chevrolet or Holden. Drill hole in your air cleaner-to-throttle body pipe, and hot-glue the IAT in place. Or use JB-weld. Threaded bungs are available if you want to get really fancy.
* MegaManual * GM IAT Sensor 12146312 $10 RockAuto.com * GM sensor connector 12162193 $5 RockAuto.com
Fuel System
Use a external EFI fuel pump, connected to the stock fuel line coming from the tank. We have selected a 51-psi system, so need a pump capable of high-pressure.
* Carter P74015 $70 rockauto.com
Run a regular low-pressure fuel line from the regular back to the the tank, and Tee it in to the filler hose. If you keep the tank above 1/4 full no baffles or surge tank are needed.
From the fuel pump output to the fuel rail, use EFI-rated fuel hose and EFI hose clamps. Use a 280ZX-style fuel filter.
280ZX EFI fuel filter $3 RockAuto.com
Ignition and Distributor
The ECU can take the RPM signal direct from your existing points-based distributor. It's also compatible with electronic ignition distributors.
Wiring
Wire up the MegaSquirt harness
- 12V
- earth/ground
- fuel pump relay
- injectors
- IAT signal & ground/earth
- Air Regulator
- EFI Water Temp
- Tach signal (coil negative terminal)
For full details, see http://www.megamanual.com/mtabcon.htm#wire
ECU
Buy MegaSquirt II fully assembled about $400 USD or $500 AUD off eBay.
ECU Configuration
Download at http://www.diyautotune.com/softwarelinks.htm
- Mac
- Windows
- Linux
You have a choice:
- TunerStudio free version (most popular software for MegaSquirt)
- Free version supports all MegaSquirt features
- SuperTunix open source
In the software configure
Fast Idle Valve (FIdle): Solenoid Fast Idle Threshold: 120F
Nissan temp sensor -40F 30-33000 ohms 80F 2000-2500ohms 160F 360 ohms
CONSTANTS Required Fuel * displacement 1397cc (A14) or 1488cc (A15) * # of cyl 4 * injector flow rate 188 * desired AFR 13 Injector open time 1.0ms batt V correction .20 PWM current limit 1000% PWM time threshold 25.4 Fast Idle Threshold Barometric Correction: Off Control Algorithm: Speed Density [non-TPS] Injections per Engine Cycle: 1 squirt Injector Staging: simultaneous Injector Port Type: multi-port Engine Type: even fire
VE TABLE
Generate a new table based on your peak horsepower and torque figures ('Settings/VE Table/Tools/VE Specific/Generate VETable').
ENRICHMENTS EGO Step (%): 0 Warmup enrichment -40F 180% -20F 150% 0F 140% 20F 135% 40F 130% 60F 125% 80F 118% 100F 110% 130F 103% 160F 100%
Afterstart Enrichment: between 25-45%for 100 to 250 cycles,
Software Tuning
Start your engine and let idle. Go to http://www.megamanual.com/v22manual/mtune.htm
And start tuning.
A big help in turning is to fit an Air Fuel Ratio Gauge. MegaSquirt 2 can directly read the wideband output of the wideband controller, but more importantly you can see the A/F Ratio on the gauge.
See Main Article: Oxygen_Sensor#Air_Fuel_Ratio_Gauge
The paid version of TunerStudio has a software auto-tuner which is supposed to be great, but it still requires some work (it's not totally automatic).