Originally Posted by AndrewCologne (Post 10891272)

The classic Retrofit is a superb solution and Im thinking of purchasing one as well.

Originally Posted by AndrewCologne (Post 10891272)

Hi Sub8,

well, till now no production in series is planned. This is a private handmade prototype and it's tested since about 18 month. It's developed concept and coding routines are done by myself with assistance of an engineer of electrical engineering regarding the electrical assembly.

Further questions regarding costs or purchasing in this state via PM.

The classic Retrofit is a superb solution and Im thinking of purchasing one as well.
But regarding this ECU concept the thought of a "pseudo mapped" injection with still a K-Jet is not possible.

The solution above till now is totally lambda based, means till now no further hall sensors, no further mapping sensors or whatever need to be installed.
For optimal plug'n play compatibility without any further electronical modifications I kept the original wiring and sensor signals. Means the existing throttle switches i.E.
The only further swap which is needed is the little 15c switch on the right chain housing which will be changed to a 120°c sensor, enclosed with the ECU unit.

So the old ECU unit will simply changed with this one where the LCD-display – if connected – can be put into the ash tray for realtime reports while driving. Adjustments via software will be done via USB.

http://andrewcologne.bplaced.net/911/ECU/ecu-sc-911.jpg

The optimal mixture will still be achieved by the frequency valve which is driven by this ECU as before. But as here a CPU is handling the whole job, its possible to optimize many engine running states like a smooth idle, direct and optimal lambda 0.85 enrichment at acceleration or WOT and ... the support of Bosch LSU based wideband sensor controllers on the market like Innovate, PLX, AEM is given. With that it could also be possible to achieve specific mixtures for idling, cruising and accelerating/WOT. I think thats your point.

It will work with the original unheated o2 sensor, the heated o2 sensor from the 3.2 Carrara and as mentioned above with wideband sensors/controllers.


While developing and testing I and two other testing people with the same 930/16 engine figured out many interesting behaviors of the K-Jet of these US SCs.

Originally Posted by mysocal911 (Post 10891400)

Surely your Nano processor has enough memory left that you could include a digital ignition system in your present
Lambda controller, right? It's not that difficult, actually less complex than controlling the mixture.

Originally Posted by AndrewCologne (Post 10891418)

Hi Dave,

thats what I've been thinking about also.
Reading/passing the (TD) trigger signal between the dizzy and the CDI.
But as till now I was totally in that process of coding/testing/coding etc. of the lambda core, this could be a forthcoming option.

Originally Posted by Sub8 (Post 10891407)

Yes that exactly what I meant! :)
Let the CIS give you lambda 1 and your box allows everything (well almost) that you would want a 3D mappable solution to do without any of the hassle.....

Originally Posted by mysocal911 (Post 10891429)

Using the Nano, my ignition design for a six cylinder BMW took about 60 lines of C code with Nano's interrupt input sensing
the distributor signal.

Originally Posted by AndrewCologne (Post 10891439)

@ Sub8
Here a video where the needed lambda 0.85 spot for accelerating is perfectly hit and kept when using a wideband sensor with this ECU.

https://vimeo.com/409686215

Originally Posted by mysocal911 (Post 10889053)

Was this done? With that done and with the O2 sensor disconnected, the duty cycle should be close to 50%, if not the Lambda ECU is bad.
Again, the Lambda system is extremely simple to diagnose!

Originally Posted by Funracer (Post 10894606)

Car running, O2 disconnected, AEC unplugged DC did not go to 50% and did not change at all.

Originally Posted by Bob Kontak (Post 10889024)

Another simple test is to check the unplugged O2 sensor side of that connection while the car is running. Let it warm up and it should read between 0.1V to 0.9V. 0.1v indicating lean exhaust. 0.9V indicating rich. You literally can get your idle AF mixture roughly close to 14.7:1 by adjusting the 3mm adjusting screw until it reads 0.5V.

Originally Posted by Funracer (Post 10895985)

Did this today. It showed .8V, too rich. As I turned the mixture CCW towards lean it went lower .7V and then dropped instantly to .3 MILLIVOLTS! I tried to reduce it to .5V many times but it did this every time. There was no reading between .7V and .3 millivolts. This is a brand new sensor I installed back in February.

I have 2 other O2 sensors that tested good today. I will put one in tomorrow and see if it works better.

Originally Posted by Funracer (Post 10895985)

Did this today. It showed .8V, too rich. As I turned the mixture CCW towards lean it went lower .7V and then dropped instantly to .3 MILLIVOLTS! I tried to reduce it to .5V many times but it did this every time. There was no reading between .7V and .3 millivolts. This is a brand new sensor I installed back in February.

I have 2 other O2 sensors that tested good today. I will put one in tomorrow and see if it works better.

Originally Posted by mysocal911 (Post 10896370)

Why are you now worried about the O2 sensor voltage? Focus on getting the DC to 50% without any inputs on pins 2,7,12,14
(pins 7,12,14 must be above 5 volts, pin 2 at about .50V).

Originally Posted by AndrewCologne (Post 10896145)

Yes, its very difficult as you must hit the CO mixture that precise so it exactly results in the ballpark for a proper Lambda 1 reading, means 0.1-0.9v. Just a 1/16 turn already affects the mixture significantly seen with the eyes of an O2 sensor.
.

Originally Posted by mysocal911 (Post 10894781)

1. What is the duty cycle?
2. When running with the ECU connected and the back of the connector cover removed, measure the voltage
at pins 2, 7, 12, 14.