Ok, enough of this bullshit. I have built the 2 transistor schematic listed on aldlcable website over 3 times. I even had it built for the fourth time professionally. It does not work. My car is a 91 with a 730 ecm. I have tried everything. It will not pass the moates aldl cable echo test on any pc. I have tried 3 different pc's. Yes, my com ports are correct. I am a pc technician also. WTF??????!!!!! I have been trying to build this thing for weeks now. Losing a lot of sleep too. Like i said I had it professionally built the fourth time around. I repeat , this schematic DOES NOT WORK PERIOD! All of my parts are correct. I repeat ALL OF MY PARTS ARE CORRECT! ALL of my transistors are correct as far as collector, base , emmiters. Diode cathode is facing the correct direction. I am totally baffled here.

1. 1n4148 diode
2. 2 2n3904 transistors
3. 3 10k ohm resistors
4. new db9 connector

 

Yes, I have a 12 Volt source also, and a correct ground. Even tried connecting directly to the ecm throught the a8 serial data line orange wire. Still no go. It will not pass the moates, or datamaster echo cable test either. I repeat, this was professionally built cable by an electrical engineer also.

 

That schematic on the web that supposedly works for people , does not seem to work for me what so ever. I am totally baffled here. Totally

 

I have tried Tunerpro Rt with correct bin, and all necessary files, EFI live, TTS Datamaster , also Disable handshake on Datamaster and played with ALDL link timing with no success, I have tried Freescan also. None of these will work. Like I said this cable will not pass any of the cable tests out there either. Does anyone know of this schematic or tried it? I have tried all new parts over three times, even tried an actual new serial cable. Tried the echo test on 3 different computers( all com ports set up correctly). This is bull-****! At this point I don't think it is possible to build your own serial to aldl interface cable. It just isn't possible.

 

Or is it possible? Someone please help

 

did you see the thread above?

 

I built the exact same one, and winaldl connects without issues. Tunerpro is sketchy. If you are using a serial to USB adapter, you have to make sure you have the driver set right(COMM port settings) and the 10K resistor bridged across pins A and B for 165 ECM's. Bridge the 10K resistor, turn the key to the on position, then hit connect. Don't use the ALDL ground pin. There is alot of noise on that one. Ground your cable on a good chassis point.

 

Will winaldl work for 90 and up 730 ecm's?

 

yes it should. It reads the data stream at 160 baud but at least its relaible. Heres a screenshot of it doing its thing on windows 7.
On the 7730 ECM's, the 10K resistor should not be needed.

 

ok, i will give winaldl a shot today. Think I may have found the prob. I believe that since my car was originally a tbi car, the owner never changed the harness over. It appears to be the tbi harness! I will check and confirm that for sure later on today. Anyhow, the pcm is the 730 and the engine is the 350 tpi with correct prom/memcal etc.

 

WinALDL won't work on the '7730 ECMs. It is 160 baud only while the '7730 ECMs are 8192 baud only.

The lack of a 10K resister is correct. Don't use it with the '7730 ECM.

On TBI cars the ALDL serial link is on pin E. While on '90 - '92 TPI cars it is pin M.

RBob.

 

Rob, i know that already, I did take a second look at the harness at the ecm and it does have the correct tpi 7730 wire colors afterall. So, why can i not connect? This time i had an electrical engineer make me a cable using the max 232 chip. Tried pins e and m. Also tried connecting to a8 orange serial data wire on ecm. No go. Tried tts datamaster, efi live, freescan and win aldl. What in the world is preventing me from hooking up? Should i just break down and buy a cable?

 

Do you have the correct datastream defenition for your ECM/car?

 

This is the one i've used for many years, it's never failed me.





I've only used it on '7730's.

 

Trace the ECM datastream pin to the ALDL connector. All you need is a simple voltmeter.
Why not ask the electrical engineer building the circuits if the 2 transistor design is wrong or not......and why it won't connect?

 

Traced the wire. It is an orange wire and it is BA8 on the actual ecm . What am i supposed to do with the voltmeter? I did confirm that this max 232 cable does work with my desktop, meaning that it passes all of the moates aldl cable tests. Just wont work on the laptop.

 

That means they wired the ALDL pin correctly. The problem is you are trying to power the cable off of your RS232 interface and your laptop can't provide the current. Change the RS232 wiring to power off of the car 12v or a 9v battery instead of the RTS & DTR signals.

The voltmeter is for wire tracing. Set the scale to continuity and probe pin M and E to pin A8 and A9. No need to trace the wire by hand through the wiring harness.

 

If you have an open USB port on your laptop you can use it to power the ALDL circuit as well. I've done this with many other specialty circuits at work. I also used it in my bluetooth datalogging experiments a few years ago.

 

ok, here is the schematic I used. http://www.techedge.com.au/vehicle/aldl8192/8192hw.htm

Now, you are saying to connect 12volts to the number 1 or vin on the 78L05 ? Is that where to connect it to? and you are saying to first disconnect both of the diodes that go to pins 4 and 7? Just confirmed that the cable i built does pass the moates test on a second desktop too. It also has no problems with the hyperterminal test either. It will pass the hyperterminal test in the laptop, but wont pass the moates aldl echo test on that laptop. I do think it is a voltage issue too. Thinking about using a serial to usb adapter and then see if it connects like that. Let me know what you think

 

So how do i steal more power from the usb port and give it to the aldl serial cable? explain.

 

There are 4 pins on the USB plug, 1 is +5V and 4 is ground. I usually find an old USB mouse at work and just cut the cord off of it.





No need for the 7805 with USB power.

 

Hey man,thanks for the info. I don't mean to be a pain,but can you show me exactly where i would connect to on my schematic. Also, would it hurt anything to keep the78L05 regulator? http://www.techedge.com.au/vehicle/aldl8192/8192hw.htm
There is the link again. Would i connect the red usb wire to say, U2 (+5v) on the schematic? let me know.

 

it won't hurt anything to keep the regulator, however i'd run the USB power to the output side of it (USB 5V to pin 3 and gnd to pin 2). the 7805 pin numbers in your linked diagram are incorrect.




At least if you leave the 7805 you can also wire in a jack for a 9V battery if your USB ports are tied up.

 

I know there are 2 pins incorrect. We did discover that while we were making it.What about the diodes on pins 4 and 7 of the db9? Shouldn't i disconnect those first?

 

It shouldn't make any difference but for the sake of a clean circuit i'd remove them.

I've never been fond of the circuit on that page, many years ago i did put it together on the breadboard and got it working but it always seemed buggy.

 

Ok, got the cable working as far as passing the moates aldl test on the laptop now. Cut the two diodes on pins 4 and 7 and used a 9volt battery. Still not connecting to the car. Pcm not detected! WTF? Need help please.

 

you sure you have A and M going to the right spots on the ALDL port?

 

Yes I even connected directly to the ecm serial data line, which is Ba8 on the ecm(orange wire). Cable always says it is good until i connect it to the aldl port , then tunerpro says , cable not found.

 

Maybe , i will try later without grounding the cable. Because, it seems to stop working when i connect it from the laptop to the aldl. Works fine when just connected to the laptop, passes all of the tests, etc.

 

I probably have all the parts, if i get a chance tonight i'll throw it together on the breadboard and hook it up to my '7730 test bench and see if i can figure anything out.

You need the ground reference for the signal though.

 

it's together on the breadboard and passes the cable tests just fine, i'll hook up the '7730 to it tomorrow after work and see what happens.

 

Here is what i found...

If your ECM is powered up and hooked to the ALDL circuit and you run the cable test in Tunerpro it will fail the test. Even though it says it failed mine still worked fine.

Once i turned off the ECM, even with it still hooked up it would pass the test.


Don't mind the messy desk but on the breadboard is the circuit you linked to minus the 7805 (I used a variable DC power supply) hooked up to a '7730 and communicating just fine. I even threw some LED's in there to act as TX/RX and TTL data indicators.

 

i use the techedge schematic for all of mine, never had an issue with them... i also use 2.2uF caps, if that makes any difference.

 

I am using the techedge schematic, and had it professioally built. Still won't connect in tunerpro or any software for that matter. Using the max 232 chip too. I am starting to think that maybe datalogging isn't possible with a hypertech prom?

 

My caps are all 3.3uf (c1-c4) and a 1uf for c5 i believe and a 3.3 for c6

 

are my caps for c1-c4 too big?

 

I used 4.7uf Tantalum caps, http://www.alliedelec.com/search/pro...px?SKU=8817176

 

After going through this last year, and shedding the same tears, and builing more interfaces than i care to remember, I used the techedge diagram, made a couple of ALDL interfaces for friends. They all worked.

The problem was the RS232 port on the friends computer.

They have to be able to switch to a 8192 baud rate for the '730pcm which not all RS232 interfaces on PCs can do. The trick is to pickup an FTDI based usb to 232 converter.. ( luckily they are only cheap ) which does switch to 8192

heres one that I have purchased and know works.

http://www.parallax.com/Store/Microc...%2CProductName

If you have a Frys electronics nearby, they stock em..

Install the latest driver from the ftdi website.

( Oh and the 2 transistor one does -not- work for your car, I have tried it also.. )

 

I had a bad ecm. Problem solved