My project car is a BMW E30 from 1984. In 1996 the car had been rebuilt and got a 325i engine with a TD04 turbo.
Since then it has got some major improvements like limited slip differential, intercooler, water injection, etc.
Engine management remained Motronic 1.3
Now it suffers from the lack of engine control, sometimes knocking sometimes coughing, that's why I'm here, and want to see a GenBoard inside! :)
Current setup
These are engine outlines (and details) before changing anything:
- Engine: M20B25 (325i from ~1987) 2500cc, 6 cyl inline, 12 Valves, SOHC (stock, but lowered compression) [Engine bay(huge pic)]
![[Engine bay(huge pic)]](http://quasar.dynaweb.hu/~lezsi/bmw/original/PICT0004engine-bay.JPG){kind=link}
Trigger
- stock 60-2 VR crank-trigger from Motronic 1.3, stock coil, mechanical distributor (guess it has no mech. advance), stock sparks. See MembersPage/GergelyLezsak/Trigger
- some inductive sensor from ignition cable (cyl. 1?) for cam position. See MembersPage/GergelyLezsak/CamPos
- Ignition outputs: wasted spark seems like a good choice for this engine. More: MembersPage/GergelyLezsak/Ignition
- Fuel injection: Bosch injectors from E36 325i (part no. 0 280 150 415) maybe 190 cc/min @3.5bars. R=~16 Ohms (high impedance)
- Staging injector: Bosch no. 0 280 170 400. It comes from the jetronic cold start inj. (not a PWM system!), maybe 113 cc/min @3 bars, R=~3 Ohms. Actually switched by ~half throttle pos.
- Adjustable fuel pressure regulator (home made, seems working, no fuel pressure meter altough). See MembersPage/GergelyLezsak/FPR
- Water injection. High pressure pump (headlight washer), unknown injector. Actually switched by ~half throttle pos. See MembersPage/GergelyLezsak/WaterInjection
- Turbo: Mitsubishi TD04-11B (it's a small one from 324d), internal wastegate with stock (direct pressure controlled) mech. actuator arm
- Idle control : stock solenoid, Bosch part no. 0 280 140 524. See MembersPage/GergelyLezsak/IdleControl
- Intake: guess it's stock AFM with direct filter. Factory throttle pos switch (3 state; idle, between and WOT). See MembersPage/GergelyLezsak/TPS
- Sensors: Two coolant temp (seems stock) at thermostat housing. See MembersPage/GergelyLezsak/WaterTemp
- 1. (one pinout) shows 120ohms @25c
- 2. (two pins) shows 2.18kohms @25c (this one sounds pretty standard temp sensor)
- Sensors 3: There's no O2 sensor, and there's no IAT (excepting the one may be included in AFM housing -which has to go either). There will be a WBO2 mounted, I guess. It's a must for sure.
Project plan
Current goal : Achieve maximum power output from current mechanical design with reliability in the long run. Good driveability and fuel economy is also in sight.
Future plan : Additional mechanical improvements possible (larger injectors, big turbo, etc.)
Suggestions
How to start? -I think it's easier to go by little steps. Maybe I try to control EFI first and leave ignition to motronic.
Issues with this configuration:
- I have to share crank VR signal between two computers. Measure the mean voltage (DVM, DC Voltage measurement) on the VR transmitter pins (on the ECM side, while ignition is on). engine need not run. If it was 0V, sharing the 60-2 crank VR signal would be smooth.
- Bad news: There's a ~5V DC signal from the ECU. To share this signal, a series capacitor ("high-pass" filter) is needed so the AC is passed but DC is not. Min. value is 10uF (25V or higher recommended) - easy to mount onboard
- make sure there is no serious current flowing on the GND connection of the VR sensor (VR-). It is very easy to inject 40..150mV noise that can be problematic at very low RPM (cranking). When two ECUs are connected, the GND easily picks up some noise so special care is needed.
- TPS is also problematic, I need to replace WOT switch with potentiometer, therefore I'll lose acceleration ignition retard - I guess.
- with a good MAP sensor the lack of TPS is bearable. You'll need TPS for a nice boostcontrol though.
- Maybe It'll be left off from the first configuration.
- with a good MAP sensor the lack of TPS is bearable. You'll need TPS for a nice boostcontrol though.
- M18x1.5 mm female thread in exhaust after the turbo would be nice for WBO2
- consider ExhaustGasTemp (will be a small appr. 10 mm drill in the exhaust before turbo)
- get a wastedspark coilpack. Common to use Ford EDIS packs, but Opel or VW might also be an option
- 3 transformers with 2 high-voltage terminals each)
- or get 2 coilpacks if you can only get coilpacks for 4 cyl (there will be a spare)
Suggestions are appreciated...