- Tue Sep 13, 2022 4:29 pm
#58590
Hi All,
I've always been fascinated by ECUs and I think it's time I got stuck in. This will hopefully be a build log/reference for developing an ECU for my Porsche 996.
As standard the car has a Bosch Motronic 5.2.2 - it's a very early car with a cable throttle so has a slightly simpler ECU than a later 'e-gas' car.
I've like to make this ECU plug and play as much as I can - so that means using the standard 'dumb' coils so from what I've seen I'll need ignitors to run them.
As the engine is a flat 6 it has two completely separate exhaust systems to the two tailpipes so two wideband sensors will be required which is a bit annoying. I think the best solution here is to combine the information from both sensors to give an average reading? This will clearly also need an external controller. I would like for the wiring for these to be the only external wiring required.
Flywheel is 60-2 which is good, hall effect sensor.
There is one cam sensor, which I also think is hall effect. Need to check this.
The motor has single stage variable valve timing on the inlet cam which is triggered by a relay, should be easy enough. There is also a resonance flap in the intake which opens from 2500-5000 rpm roughly, vacuum actuated again via relay.
An oil pressure gauge connects directly to the dash, it would be great to be able to log this data too as it's currently 'dumb'
I think it looks likely that I'll run wasted spark ignition and will start off batch firing the injectors although I would like to go sequential - looking at pizi88's work on the BMW speeduinos this looks doable if I can copy his homework. I guess an adaptor board is the best way to go about this.
First port of call finding a decent pinout of the Motronic ECU and joining the dots.
I'm a design engineer by day but have been looking to expand my electronic skills so I'll need all the help I can get. Luckily my buddy is an electronic engineer so I'll be running a lot of stuff past him too.
I've always been fascinated by ECUs and I think it's time I got stuck in. This will hopefully be a build log/reference for developing an ECU for my Porsche 996.
As standard the car has a Bosch Motronic 5.2.2 - it's a very early car with a cable throttle so has a slightly simpler ECU than a later 'e-gas' car.
I've like to make this ECU plug and play as much as I can - so that means using the standard 'dumb' coils so from what I've seen I'll need ignitors to run them.
As the engine is a flat 6 it has two completely separate exhaust systems to the two tailpipes so two wideband sensors will be required which is a bit annoying. I think the best solution here is to combine the information from both sensors to give an average reading? This will clearly also need an external controller. I would like for the wiring for these to be the only external wiring required.
Flywheel is 60-2 which is good, hall effect sensor.
There is one cam sensor, which I also think is hall effect. Need to check this.
The motor has single stage variable valve timing on the inlet cam which is triggered by a relay, should be easy enough. There is also a resonance flap in the intake which opens from 2500-5000 rpm roughly, vacuum actuated again via relay.
An oil pressure gauge connects directly to the dash, it would be great to be able to log this data too as it's currently 'dumb'
I think it looks likely that I'll run wasted spark ignition and will start off batch firing the injectors although I would like to go sequential - looking at pizi88's work on the BMW speeduinos this looks doable if I can copy his homework. I guess an adaptor board is the best way to go about this.
First port of call finding a decent pinout of the Motronic ECU and joining the dots.
I'm a design engineer by day but have been looking to expand my electronic skills so I'll need all the help I can get. Luckily my buddy is an electronic engineer so I'll be running a lot of stuff past him too.