This page documents ECU features to be utilised in the EJ25 N/A DOHC installation
| Feature | Spec | Hardware utilised | Software support | Priority |
| Sequential injection | 4 x 11.5 Ohm / 270 cc/min injectors | 4 x injector drivers | Yes | - |
| Wasted spark ignition | Diamond F-569 coilpack. 0.62 - 0.76 Ohms primary, 17.9 - 24.5 K-Ohms secondary. | 4 x ignition drivers | Yes | - |
| Stepper idle control | Stepper outputs | Yes | - | |
| Fuel pump | Fuel pump relay output | Yes | - | |
| MAP | 0-5V range | OEM external pressure sensor (Auto and Turbo models only?) | Yes | - |
| LCD | 4x40 LCD output | Yes | - | |
| Dual wideband lambda | Bosch LSU | WBO2 channels 1 and 2 | Partial (comparison and range testing should be done) | Low |
| EGT | EGT sensor | Partial (is this used for more than display?) | Low | |
| Knock sensor | "AC voltage output" | Knock channel | Partial (is this used for more than display?) | Low |
| Cooling fans | 2 relay outputs | Partial (only 1 fan switch is supported) | Medium | |
| Subaru crank trigger | 87/32 degree signal, TDC 10 before. Magnetic VR | VR 1 | No | High |
| Subaru cam sync | 1,2 or 3 pulses to determine cylinder, so order is important (eg, to know cyl. 1 vs cyl. 4). Magnetic VR | VR 2 | No | High |
| EGR Valve | Solenoid | Misc driver 1 | No | Medium |
| PCV Valve | Solenoid | Misc driver 2 | No | Medium |
| Pressure Select Valve | Solenoid (manifold/barometric select) | Misc driver 3 | No | Medium |
| EVAP Valve | Solenoid | Misc driver 4 | No | Medium |
| Warning Lamp (CEL) | Dashboard lamp | Misc driver 5 | No | Low |
In [MoSCoW] parlance: High = Must Have, Medium = Should Have, Low = Could Have.
[dnb]Very interested to see how this goes...
The MAP sensor is indeed only present on turbo cars.
- And 95-on autos, although I'm not really sure why...
- Turbos are likely to be low impedance, but I've measured the resistance on my 2.5 NA as 11.5 Ohms.
- Any idea what size these are? Low impedance injectors aren't ideal for VEMS... Why did Subaru use side feed injectors???
- My local shop couldn't flow test the side feed injectors! Internet lore says 270 cc/min for Subaru red-top side feed injectors.
- Any idea what size these are? Low impedance injectors aren't ideal for VEMS... Why did Subaru use side feed injectors???
- Very cool. That's Plan-B, as I'd prefer to go P'n'P.
- With you on the P&P, but I'm just covering all eventualities (and taking the 'easy' option for me.)
- Possibly. I was mostly hoping to have control to ensure I've reading the correct pressure source (eg, the manifold).
- I was going to remove this solenoid from mine and do the plumbing directly!
- Fair enough... :-)
- I was going to remove this solenoid from mine and do the plumbing directly!
- Where were you going to put the MAT sensor? This is only present as standard on some WRX STIs if I remember correctly, and the sensor placement is far from ideal for VEMS.
- Tough question. Is it possible to use two - one in the inlet tube to avoid heat soak, and one in the plenum or manifold to avoid inconsistent temp readings - and switch over at a preset point, or when the two values are equal? Failing that, I guess the airbox before the throttle body might be best compromise?
- Evap/carbon can thingy would be very useful for a number of my projects - the sooner this is available the better. I have proposed an algorithm but not had time to test things yet. It can be different to the standard system since we have good wideband control over the fuelling.
- Not sure why you need 2 wideband channels on the Subaru, however this would be a VERY useful feature to have for the v8 users here...
- It's not really necessary for VEMS fueling, but the factory system uses 2, one before the cat and one after - presumably to check that the cat is working? I was thinking side-to-side to give an indication if anything is amiss with a cylinder ban, or factory style to show if the cat had problems.
- FWIW, I was thinking the other day that a 52 mm gauge with 4 x EGT, 4 x WBO2, and 4 x CHT would be very useful in some circles... (eg experimental aircraft).
- On my turbo, the PCV is passive and requires no ECU involvement. (It's replaced with an oil catch system now too).
- OK, I'll double check. It's only active when the engine is running so ECU action isn't really necessary.