How do I check whether my car supports OBD I diagnostics?
Make sure the vehicle has VF1 (ENG), TE2 and E1 pins in the diagnostic connector and that diagnostic data is output to VF1:
1. Switch the ignition off
2. Bridge TE2 – E1
3. Switch the ignition on
4. Measure the voltage between VF1 – E1
If the voltage fluctuates between 0 and 5 V and the Check-Engine lamp flashes frequently, you can build a cable and connect to the car with MyEngine. If not, your vehicle most likely does not support this type of diagnostics.
Which settings should I specify on the «Fuel» tab for my engine?
In MyEngine you must enter the injector flow rate, the number of cylinders and the number of injector firings per two crank-shaft revolutions. These data are required for correct fuel-consumption calculation. The table below lists these parameters for some engines. You can start with the injector-flow values from this table when using the program for the first time; later it is recommended to calibrate the injectors (procedure described below) to obtain an exact value.
Injector flow rate for some Toyota engines:
| Engine | Production years | Injector flow, L/15 s | Cylinders | Injector firings per 2 rev. |
|---|---|---|---|---|
| 1JZ-GE, 2JZ-GE | 1992-1996 | 0.0825 | 6 | 1 |
| 1JZ-GTE | 1992-1996 | 0.0950 | 6 | 1 |
| 2JZ-GTE | 1992-1996 | 0.1340 | 6 | 1 |
| 1JZ-GE (VVT-i) | 1996-2000 | 0.0630 | 6 | 1 |
| 2JZ-GE (VVT-i) | 1996-2000 | 0.0785 | 6 | 1 |
| 1JZ-GTE | 1996-2001 | 0.0950 | 6 | 1 |
| 5S-FE | 0.0560 | 4 | 1 | |
| 5A-FE | 0.0440 | 4 | 2 | |
| 4E-FE, 5E-FE | 0.0390 | 4 | 2 | |
| 4E-FE | >1995 | 0.0440 | 4 | 2 |
| 1G-FE | 0.0390 | 6 | 1 | |
| 7A-FE | 0.0400 | 4 | 1 | |
| 3S-FE | 0.0550 | 4 | 2 |
How can I determine the exact injector flow rate taking wear into account?
Calibrate the injectors:
1. Enter a known or approximate injector flow in MyEngine — suppose 0.044 L / 15 s.
2. Fill the fuel tank to full and reset all readings in MyEngine.
3. Drive more than 100 km in various modes while MyEngine tracks fuel consumption.
4. Refill the tank (preferably at the same station and pump). Note the real fuel used and compare it with the program’s reading.
5. Calculate the real injector flow: X = (Real_Fuel_Used × 0.044) / Program_Fuel_Used
6. Enter the result in the program settings.
What does the «Saved» parameter mean?
Shows the approximate amount of fuel saved while driving in deceleration fuel-cut (coasting) mode.
To enable this parameter, tick «TEST: Account for fuel-cut idle» on the «Fuel» tab.
Why is this option marked TEST?
Because full support for fuel-cut has so far been verified on only one car: tests on a Toyota Cresta JZX101 with a 2JZ-GE VVT-i (3.0 L, AT) showed that protocol flag 11.5 indicates whether fuel is being injected. Additional conditions (closed throttle and speed > 0) were added. On this car fuel cut-off works in gears 2, 3 and 4, verified by the stock cruise display.
To see fuel cut-off, display «Instant fuel consumption per 100 km»; when cut-off activates, it becomes 0.0.
Which sensor readings are considered normal?
They depend on the specific vehicle, its year and engine. Below are tables of main ECU parameters (injector pulse width, ignition timing, IAC position, MAP reading):
Can I connect to a diesel vehicle?
Yes. A Drom.ru user successfully connected to a diesel Toyota Cresta LX90 2L-TE and shared a log recorded with CarTester. Download the log.
[Added 17.05.2012] Another Drom.ru user connected to a diesel Toyota Hilux Surf 1998 with a 1KZ-TE engine.
Will there be versions for Windows Mobile or Android?
No.
Will there be a Linux version?
No. But MyEngine works under Wine. Comment from a Drom.ru user:
P.S. For Linux users (myself included): MyEngine runs fine through Wine; just create the symlink
ln -s /dev/ttyUSB0 ~/.wine/dosdevices/com2
Can I use MyEngine on a car with OBD II?
No. OBD I and OBD II are incompatible.
OBD I is obsolete! Why do we need this program?
There are many programs for OBD II and CAN — they are indeed more advanced. But OBD I was initially neglected, and there are still plenty of such cars!
Can I get the MyEngine source code?
https://github.com/primavistalab/MyEngine
