Im trying to make an ALDL cable to connect my laptop to my 730ECM. I have a 9pin COM port on my laptop and I just found a cable to fit it today. I have studied the images Ive seen and diagrams also of the ALDL interface cables....but Im confused about the 10K and 3.5K transistors and resistors. Can somebody simplify this for me? Im using the WinALDL software but also have ALDLMon for a backup. DO I use the 10K transistor on the inline side of the cable that connects to the laptop or ECM??? and do I have to ground the A and B on the ALDL?? Help....I just dont want to blow my ecm up or my laptop. Thanks in advance....

Do a search for aldl diagram. I believe theres a few results.

I'm not sure what you don't understand.

Craig told you on this thread that you don't need the 10k resistor on a '730. It's not hard to build the standard board and either disconnect this resistor or leave it in (check to see how it affects your timing if you do).

I've built the 2 transistor interface and dropped the board with untidy transistors and resistors onto the floor of the car, shorting badly enough to let the smoke out and burn one of the board tracks out. Total cost to repair, about $0.02. Be adventurous- you could have this sort of drama too.

I still have a working laptop and ECM- you might not be so lucky, but '730's are cheap

John

Maybe I did it wrong, but I simply soldered the transistor directly to the pins on the DB9 connector. It took some doing, but it worked. I don't have the luxury of a PC board manufacturing set up. Maybe I'll find out that it doesn't really work later in the game.
EDIT: Please, nobody "Napster" me for this. I hope I don't infringe on anyone's intellectual property rights. (For more information, see previous posts that got a little nasty...Mr. Mangus, you ROCK!!! Screw that guy!!!)
Anyway...I built my cable using the one-transistor diagram that you can find on the web. I don't have the address, but I'll post it for you in a little while. There is one major difference (other than the two-transistor design) that is immediately apparent to me (a newbie). The diagram for the two-transistor cable shows that you hook up to pin G on the ALDL port. My ALDL port doesn't have anything there, although it is supposed to have the FUEL PUMP PRIME/TEST connector there. My FUEL PUMP PRIME/TEST connection is actually under the hood near the fuel pump relay. I checked it several times and everything I can track down points to that shrouded connector as being such. The DATA TX pin on the one-transistor cable shows as being pin E on the ALDL port (5th from the left on the ALDL viewed from the front). I hope I did it right. I haven't smoked my ECM yet and I want to keep it that way.

Go to radio shack and pickup some empty pcb boards. They are usually a couple bucks at most and they make it easier to hookup everything right.

This is good advice. I did mine that way too. See if you can get a small board with tracks that run (some short and some long) both lengthwise and widthwise. This makes it easier to get tracks to where ever it's easiest to position the electronic components.

As for Jeepguy's stuff on the one transistor board, this is interesting, but offtopic as far as Kyl98's thread is concerned. AFAIK, the '730 is 8192 baud only. The one transistor interface only suits 160 baud ALDL.

John

PS. Building your own ALDL interface connection and cable is a great beginner's project. It's very satisfying to see this work. It took me two goes to get it right- I hadn't done any electronic stuff for 20 years. Then I got brave enough to build my own eprom programmer, and then a DIY WB O2. Just keep soldering and checking stuff, and plugging the holes up where the smoke escapes from and you'll get there.

So I cant use the single Transistor cable? All of this still seems kinda confusing. I did go to radio shack and bought a 5pack of 10K resistors and a DB9 connector. I only bought one switching transistor though....did I mess up? Also will the WinALDL software work with my 730? or should I use the ECM852 software from moates.net?? I was going to build the two transistor cable from his site, but it looked confusing with the "lotus" connector. Im still also lost on what pins to hook up to on the ALDL. I know ground goes to A but is the data E or M?? Or should I just try both(when I figure out the cable)?? And finally, do I need a seperate 12V power source for the cable? If somebody could possibly post a pic of their cable and the schem. they used.....that would make things ALOT easier. Thanks for all the help so far guys......

1) No. Single transistor is for 160 baud ECM's.
2) Yes. Quelle horreur! You'll have to drive all the way back and spend another 10c on electronics.
3) Nope.
4) Yes.
5) That is confusing. E is for 160 baud ALDL (on my plug anyway), and M is for the '730 (on most diagrams I've seen), but the diagram on Craig's site shows G for data. Connect to M and see what happens. Someone on this board who has tried this should help out- if not, check a workshop manual, and if that's no good, just try it anyway.
6) You don't need a separate 12v power source. Most of the diagrams show it coming from the ALDL plug (but some have taken their power from the laptop IIRC).

John

Thanks John....I appreciate all the help. What was the part number of the transistors you got?? Did you follow Craig Moate's schem. on his site for the two-transistors? And since I need 12V from somewhere(correct?) can I get it from the ALDL? or do I need 12v for anything???? sorry for all the questions....just want to get this right...thanks again.

Ive read you can steal the 12 volts from the lighter with a simple plug spliced in.

I have to use that for my laptop so it doesnt go dead. Is it ok to use the lighter outlet for both the laptop AND the ALDL 12V source???

I think it's best to get your 12V from the ALDL- although some don't. Craig's schematic has +12V at pin F and ground at pin A. Just check this with your multimeter (make sure it's at least a 20 Megohm model). I don't see why you couldn't use the lighter 12V, but why bother when you can simply include it in the ALDL plug?

As for the transistors, I just bought a few 2N2222A's or subsitutes.

John

Here is the two transistor interface that I have been using. Following this post will be a few more that shows the construction of this interface into the DB9 connector.

RBob.

Pic of complete unit. Note brass strips used to tap into the ALDL connector. Can also hardwire unit into place.

RBob.

The guts.

RBob.

Close up.

RBob.

I found that schematic on the site but noticed there are a couple different versions. Here is the version i used and works with 7730 dont know about any other ecms though.

Rbob, Thanks a TON!!.....That will definitely help out. One last question...how much did the DB9 connector run ya and did you get it at Radio Shack?? Thanks alot.....

From time-to-time I'll get stuff at radio Shack. Their project boxes (plastic with aluminum & plastic lids) are nice. Reasonable price too. I find that they generally won't have more then one of a part on the rack, if at all.

So I buy from places like Digikey and Hosfelt Electronics. DB9's are 29 cents @ with a hood at 39 cents @. Can get 5 for the price of one at R.S.

RBob.

What I did was splice the wires BEHIND the aldl, and then ran it under my carpet, so I got a little DB9 connector poking under my center console.. When I need to scan, I plug the laptop in and go.

And my ALDL is still available if I need to use another scanner, like my snap-on.

Might want to be something you consider.

-- Joe

Hey guys, I saw this thread and thought I'd post a problem I'm having with my WinALDL cable for my 1228746 ECM. I had it made by one of my EE friends according to these instructions:



I have tried all of the COM ports and verified that I'm getting a 12v power source to the cable...but I'm getting nothing. I have tried wiring this cable so that the power supply for R2 comes from the laptop AND an external power supply (radio constant power), but with no luck either way.

Any thoughts? I desperately need some data so that I can get my new crate motor to jive with my 454 TBI.

On that circuit don't use R3, and use R4 but at 10K ohms. If you have a DVM measure the voltage on ALDL connector pins A & E. It should read about 2.5 volts (key on, engine doesn't need to be running).

Then read the voltage at the DB9 pin 2 (RD) pin. Should be about 6 volts. These voltages are half the peak voltages. So if the ECM is transmitting data the DVM will average it.

RBob.

Same one I use with Freescan for the 749 and $58. Works with Craig's software on the 730/165. cheers, Bob

Thanks for the response, Rbob...however, I forgot to mention that I am not exactly following the wiring diagram I displayed (oops). I am not using the R3 resistor between pins A & B and I am not using the R4 resistor because Jonas said it was only necessary for carbed vehicles. Should I still use the 10k resistor for R4 as you advised?

Also, I will go ahead and check the voltages you mentioned and see if they are at the proper levels. Thanks for the help...I'll post the voltage data in a minute.

OK...time for a moment of humility. I have a voltage meter, but I apparently don't have a clue as to how to use it. It's not a digital model...more like an Auto Zone special. It's got a knob with the following settings:

DC V: 2.5, 50, 250, 1000
AC V: 10, 50, 250, 1000
OHM: X1K, X10K
BAT: 1.5V, 9V
DCma: 10, 250

Which of these settings should I use? Also, do I just place the black meter probe on pin A and the red meter probe on pin E to check the voltage? Also, where do I place the voltmeter probes to check the voltage on DB9 pin 2? I know I should place one probe on pin 2, but where do I place the other one?

Man, this is humiliating ...but any help will be appreciated.

OK, OK...my neighbor provided me with a little direction and I can now use my voltmeter .

The voltage between pins A & E on the ALDL connector was 4.0V and the voltage on pin 2 of the DB9 connector was bouncing back and forth between 1.6V and 2.2V, over and over. These voltages were collected with the ignition on but the engine not running. Keep in mind that I have my cable set up so that 12V is fed to R2...don't know if that matters.

Considering this data, where do I go from here? Thanks for the help...

(edit - had to correct the voltages because I forgot to turn the ignition on)

Those voltages sound reasonable. Here is what I just got at the ECM ALDL line: 1.2 to 2.3V fluctuating on the AC scale.

With a terminal program set at 1200 baud it displayed garbage data. This is expected. May want to try that. Interesting to note that two laptops work with the 2-transistor (I posted above) but my shop desk top PC does not. It doesn't display any data.

RBob.

Did you use an extention serial cable to monitor with? I'm assuming you used the laptops incar, and ran either a longer serial cable, or a longer aldl cable to your shop PC.

I'm sure you checked it.. but if you added a extention serial cable, did you check it pin for pin? I've ran into cables that do either do not have all pins connected and some that are cross overed end to end. Really can be a PITA. Bob

OK...what is a "terminal program"? The WinALDL software only offers the option of 2400 or 4800 baud, if that's what you're talking about. Also, I believe I have a 160 baud ECM, which means that I have to use a single-transistor cable design...right? I guess I'm not certain as to what you're saying I should try...can you help me out here?

All on the bench going from one PC to the next.

RBob.

Something like Procomm or HyperTerminal (windows). If the diy-efi site is up there is a program called t.exe on incoming. That is a terminal program that runs from DOS, handy.

RBob.

So, do you mean I should try one of these other terminal programs as opposed to WinALDL? In other words, my problem may lie in the software and not the cable?

Trying a terminal program is just another troubleshooting method. In the end you'll usr WinALDL to data log.

RBob.

Well, RBob...you indirectly helped me find a solution to my WinALDL cable problem!

NOTICE TO EVERYONE WITH CABLE PROBLEMS...GO HERE:

http://www.syty.huryde.com/html/misc/datamaster.htm

This is a great troubleshooting guide...turned out the only problem I had was with the COM port settings on my laptop. I just disabled all of the infrared devices and I was in business...logging data like crazy through COM1.

Please pass this valuable info on to anyone encountering cable problems...I don't want anyone else to spend months (off and on)trying to figure out why they can't get WinALDL data.

Rbob, can you post the part number for the DB9 connector? Im trying to order the stuff from digikey.com but Im having some problems with all the different part numbers. I would really appreciate it if you could do that. Thanks in advance......

Try 209F-ND at 67 cents @

Plain plastic hood as 909GP-ND at 54 cents @

That is a NorComp DB9 female with solder cups. Just double check that number agaisnt their website.

RBob.

Rbob...one more question. I finally made it to Radio Shack....and purchased my supplies. My buddy works there so I got some great pricing I have a question on some of the parts though. On the resistors....they are 1/4 watt 5% tolerance? carbon-film. Are those ok? Also...the Zener diode is a 12V model....is that right? I assumed since it was going to the M on my ALDL that is a 12V source right? Or do I need the 5V? Just wanted to make sure I got the right stuff. and finally....the transistors I got are part # 2N3904 NPN silicon? I hope I got the right stuff.....Im going to have my dads work assemble the cable considering they make high dollar machinery and have all the soldering guns...and I have no clue how to read the schematic ....lol Thanks ....just let me know if I need a different part from what I have.

I had few questions about making a cable. I am using the diagram in attachment and i m not sure where few of the connectors go. What to i do with the ones that are circled red? My understanding that they were ground, but do i connect them to the ground cable or not? Also another area circled in green, do i have to get those pins connected for some reason?
And do i need the diode that is circled in blue?
Thanks
P.S. i am trying to connect to 89 firebird with 305 TPI
It should be 8192 baud but i winaldl is for 160 baud. Which program do i use to data log?
EDIT: or should i scrap the diagram i was using and use this one?

Just did this yesterday for my 89 IROC. Works like a champ and now I've got a ton of information to go over. Best $35 bucks I've ever spent.

I used Tuner pro RT. You can pick it up here:

http://tunerpro.markmansur.com/downloadApp.htm


I used the circuit that is shown here:

http://www.home.aone.net.au/~techedge/vehicle/2tran.gif

*Notes*

I used transistor N2222A. It is a NPN transistor, or "negitive-positive-negitive" type. On the transistor schematic, the terminal with the arrow is "E", the terminal with the straight bar is "B", and the other terminal (thin line) is "C".

I used a DB9 connector and wired to positions 2, 3 & 5.

Pick up 12V+ at the fuse box "Bat" terminal.

GND is terminal "A" on the ALDL. (top right looking into the ALDL)

DATA is terminal "M" on the ALDL. (bottom right looking into the ALDL)

For MAF cars (86-89) a 10K resistor must be used between ALDL terminals "A" and "B". (the terminals you short to make the codes flash)

Hope this helps.

i just finished building the cable using the second diagram i posted and it didn't work. I didn't put the 10k resister between a and b tho. I will try again tomorrow.
I have 89 TPI

Vik
Try this diagram:
http://cable.invisibill.net/

It will not datalog using this cable unless you have a 10k resistor shorted between A & B , if you have a TPI.

I usually use WINALDL to test it to make sure it works, just make sure you go to configuration and choose the right ecm 1227165.

My buddy made on of these the other day and it works great. He grabbed some transistors and resistors/diodes and a DB9 connector box out of my engineering toolbox (i knew there was a reason i bought all that crap).

I wish i would have done this before i had bought my serial cable, but once you use it for tuning a few chips, it really comes in handy.

Good luck!

thanks, i'll give that one a try. I still need to try sticking a 10k resistor and then i will build another one. I actually have extra cigarette lighter connector thing laying around that i cut off from my g meter which i wired in.

I tried making one (The two transistor Sanjaya drawing), but I couldnt get it to connect (that whole com port thing was new to me at the time). Even if it did work for me I would have had to buy a $50 battery for my old laptop w/ the serial port. So instead, I broke into the piggy bank and went to aldlcable.com and bought there usb cable for $59.95.
It was here in two days and it works great.

If anyone wants to try my "homemade" cable, get me $5 to cover shipping and its all yours (PM me and Ill get you paypal info). I promise it didnt blow up my ECM or laptop!

Can any one tell me wire color codes? Coz I have ECU on my generator by PSI and they use old ecu with there own 4 pin connector and they r selling that diagnostic cable in 400$ that I can’t afford. I have checked all 4 wires DC Volts

1) Black = Gnd
2) Green = 5V
3) Red = 5V
4) Green with red line = 5V

How can I check which one is ALDL Pin M?
Any Idea Guys??

Please Help me....