Volla

Ok, I got my 88 S4 auto, drove like a dream then my LH decided it had enough fun and made my life difficult.

I had a look at all the awesome resources here and that helped me check everything else and confirm that the problem was my LH.

So that left me with the option of sending my LH to JDS and have it repaired......or seeing that I'm an electronic engineer I can always pretend I know something and re-engineer a plug in replacement.


This thread will cover the process of me making a replacement, plug in unit.

(Spoiler alert: I am actually a bit slow in making these posts, currently the unit is made and the car starts and idles, I'm still busy at the moment with programming the unit )

Ok, I'll post the updates when I get time.....




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19?? VW Baja Bug (Completely custom, Golf 1.8 motor, and many, many mods) - Currently my daily drive
1988 Porsche 928 S4 Euro/ROW (Black with Ivory interior) - Under ECU surgery
1982 Porsche 924 Euro (Silver with cream interior)- Gone
1982 Porsche 928 S (Manual) Euro (Petrol Blue with Blue with black and white chequered interior) - Gone
1983 Porsche 928 S (Auto, NA spec, Red, black interior) - Gone
1994 BMW 530i Manual (Maroon, grey interior) - Gone

Landseer

Make one for me while you are at it, please

Volla

I will have a total of 5 when done, most of the components require minimum quantities, and it worked out so that I can make 5. Will let the remaining 4 go after I completed programming. I can make more if more people are interested

Ok here is first part in making an LH ECU:

Step 1: Requirements

1) I need to know what each pin of the ECU connector does. In the end when everything is done I want to plug my module in and do nothing to the rest of the car and it should work.

2) USB/Serial port on the board that will allow remapping while driving/dyno

3) Possibly I would want to replicate the bosh diagnostics k/l lines, but I think that would be redundant given that the serial/usb will be able to give errors and diagnose.

4) The processor that I must use must preferably have a/d convertor, lots of digital I/O, support serial and USB, must also run fast enough so that I wont have trouble when it comes to coding.

5) Must withstand the "harsh" temperatures and EM interference that is present in a car

6) Must have lots of LEDs to impress everyone that looks at it


Step 2: Component Selection

Ok here is my list of components, I know that you can get better and the whole ARM vs. MIPS instruction sets blah blah blah...

But the components are chosen, not much gonna happen to change it.

CPU: Microchip PIC32MX575F512L 100pin TQFP
EEPROM: 256K Dont care what brand, going to use the Atmel footprint <= The EEPROM is optional, if the internal flash of the processor is not enough
Switching FET: ST Micro ST-D17NF03L <= They are monsters and completely overkill but also cheap and will get the job done
BJT to switch FET: BC848 <= Switch sitting inbetween 3.3V CPU and 12V FET
Comparators: LM239, Any brand <= Used to switch from 12V digital inputs to 3.3V for the CPU
Op-Amp: LM324, Any Brand <= Need to translate the MAF Voltage to 3.3 and the engine temp sensor, etc etc
Power Filters: BNX012, 1N4004 protection diodes, Input voltage limiting Diodes <= EMI is bad inside car, thus need to filter
Voltage Regulators: LM317 <= Need 8-10V intermediate voltage, ST493C33 <= Current limiting 3.3V supply for CPU


These components are the major components and I did not list all the masses of resistors, caps and diodes used in the circuit.

Next step: Schematics

==================================================
19?? VW Baja Bug (Completely custom, Golf 1.8 motor, and many, many mods) - Currently my daily drive
1988 Porsche 928 S4 Euro/ROW (Black with Ivory interior) - Under ECU surgery
1982 Porsche 924 Euro (Silver with cream interior)- Gone
1982 Porsche 928 S (Manual) Euro (Petrol Blue with Blue with black and white chequered interior) - Gone
1983 Porsche 928 S (Auto, NA spec, Red, black interior) - Gone
1994 BMW 530i Manual (Maroon, grey interior) - Gone

jeff spahn

We are on to something here by golly. How much?

Volla

I am going to be nice and just charge cost + shipping Only to rennlist members, other people can pay me for my efforts.

A rough estimate will be in the region of $150-200+shipping (USD) depending on the conversion rate.

You will need to desolder your connector off old LH and onto new one though


==================================================
19?? VW Baja Bug (Completely custom, Golf 1.8 motor, and many, many mods) - Currently my daily drive
1988 Porsche 928 S4 Euro/ROW (Black with Ivory interior) - Under ECU surgery
1982 Porsche 924 Euro (Silver with cream interior)- Gone
1982 Porsche 928 S (Manual) Euro (Petrol Blue with Blue with black and white chequered interior) - Gone
1983 Porsche 928 S (Auto, NA spec, Red, black interior) - Gone
1994 BMW 530i Manual (Maroon, grey interior) - Gone

Herman K

PM me for email and other contact information.

Thanks

Cosmo Kramer

Will you be able to do the LH 2.2 for the 85-86 cars as well? It doesn't have the knock or hall sensor input. Also will there be software available that could be loaded on a laptop that could be used for tuning purposes through the USB?

Volla

If the pinouts of the connector are similar, then yes no problem, its just software that needs to change.

If the PCB needs to change then I can do it if there is enough demand (at least 5 people)


==================================================
19?? VW Baja Bug (Completely custom, Golf 1.8 motor, and many, many mods) - Currently my daily drive
1988 Porsche 928 S4 Euro/ROW (Black with Ivory interior) - Under ECU surgery
1982 Porsche 924 Euro (Silver with cream interior)- Gone
1982 Porsche 928 S (Manual) Euro (Petrol Blue with Blue with black and white chequered interior) - Gone
1983 Porsche 928 S (Auto, NA spec, Red, black interior) - Gone
1994 BMW 530i Manual (Maroon, grey interior) - Gone

hacker-pschorr

A. Knock & Hall sensors go to the ignition brain (I think)
B. LH 2.2 uses the same MAF, Temp II, and crank sensors so I would imagine the only difference pertaining to this project is the pin-outs.
C. They also use the same idle / air motor or at least a similar arrangement.

For the EuroS guys, "we" don't have an idle / air motor like the 85/86 cars do. Adding one would not be a big deal to be more compatible with this system or leave as is since the stock idle system on the EuroS cars doesn't even connect to the brain. Or tune the car to idle without either.

I'd be interested in an LH 2.2 version, I'd be in for one right away and a 2nd or 3rd down the road. I'll still need the ST for ignition, this would allow me to tune both at the same time.

Nice work!!

Cosmo Kramer

Here are the pinouts for the LH 2.2

https://rennlist.com/forums/928-foru...2-pinouts.html

Volla

Hmm, sorry that connector is different than mine, mine is the 35 pin shown at http://www.electronikrepair.com/wst_page7.html

If a lot of people want it then I can do a respin of my current PCB, but put provisions so that it can take either one of the connectors (offset one of the two pinouts by a bit and route the tracks around)

But that wont happen soon, first thing would be to finish off this one, then think about future mods.

And yes, the idea is to drive/dyno with notebook on passenger seat and adjust the map in windows with an app that talks through USB.



==================================================
19?? VW Baja Bug (Completely custom, Golf 1.8 motor, and many, many mods) - Currently my daily drive
1988 Porsche 928 S4 Euro/ROW (Black with Ivory interior) - Under ECU surgery
1982 Porsche 924 Euro (Silver with cream interior)- Gone
1982 Porsche 928 S (Manual) Euro (Petrol Blue with Blue with black and white chequered interior) - Gone
1983 Porsche 928 S (Auto, NA spec, Red, black interior) - Gone
1994 BMW 530i Manual (Maroon, grey interior) - Gone

Imo000

This is some neat stuff. Very nice!

Tim Murphy

Very interesting...

subscribed

Mike Frye

<<< Very interested in a 2.2 version for the S3s. If this could be set up to display/adjust with USB, then a carputer interface is also possible, no?

Very cool stuff, please keep us posted...

Landseer

Yes, if only a later one is available, you and I would be forced to procure S4 cars.