Bill-35thAnvrsy-88

Lo all,

Anyone know what wattage resistors are used to build a ALDL cable, 1/4 or 1/2 or 1 watt or...does it matter?

I'm building a cable per http://winaldl.joby.se/aldlcable.htm. I'm a little confused with the requirement for the R3 resistor. TTS Datamaster's site indicates a need it for the 88-L98. Considering this and referencing the above site, do I just jumper the ALDL pins A and B with this 10K OHM resistor?

Thanks! I'm dying to do a scan and see the results!

Bill

Topless87

My 2-transistor set up uses a 1/4 watt resistor as does the AKM cable from Steve Ruse(I'm pretty sure because its very small, but I'd have to open it up to be sure).

And, yes its as simple as that, it just goes across a-b for the 870 and 165 ECM models. (85 to 89 I think)

william.dempsey

the wattage doesn't really matter for small current projects

Bill-35thAnvrsy-88

Thanks guys!

Bill

pcolt94

1/4 watt will be just fine. 1/2 watt will work the same just bigger resistors in size if you have the room. These signals are TTL logic signals at 4 - 5 volts with really no power dissipated by any of the componants.

Be parpared to spend some time on configurations and adjustments. If it works out of the box your lucky. Different programs have different quirks and things are not always straight forward. Get all the info you can get for your specific vett and read it. You will have to figure out that R3 resistor to see if you need to use it.

I'm now building the Max232 circuit because the 2 transistor circuit configuration will not work on some programs that I want to use. I was told I needed it on my 94 system. Hope it helps. Charge on

Bill-35thAnvrsy-88

No dice...cable no worky. The ALDL cable tester program from Datamaster shows fail on every go around and the extended test does the same thing. Just for sh__s and giggles, went into Datamaster program, hit record and I get No PCM sync. When I hit the com test button with this program, it sees the GM160 and indicates everything is good. However, I'm not syncing with the PCM. I tried both modes, with and without the 10K resistor on pins A/B on the ALDL.



Questions: 1) Does the PCM work at 160 baud? If so, I can't slow down either the cable test program or the datamaster program to that speed. Advice?

2) I've noticed other cables have a 12-volt adapter to a cigarette lighter however, the schematic I have used (above) does not show this and appears to be getting it's voltage from the RS-232 port on the laptop. Any clarity to be offer here?

3) Will I screw up my ECM by messing around with this stuff?

Thanks!
Bill

pcolt94

1) I think the 88 vett you have is a 160baud and the program should handle that, not an expert on datamaster. And you can't slow down data in a cable, the programs must be compatible.

2) I dont understand that connection either. Pin 4 is a "ready to send" connection and does not look as a source for 12 volts. Have not seen that before. I would go with the external power.

3) You are hooking up to the seial data connection which is the ECM as you know, also CCM and any other serial devices that are on that line. It's a 5 volt line and you can't get to bold and go "out of the box" in this situation. Dont ever short anything elce to that point. Always makes me nerves when I hook up trying something new and unexpected things happen. Make sure wires are secure and can't flop around or get loose. Just be carefull and follow the build as advertised. Good luck.

Bill-35thAnvrsy-88

I guess it's time to "buy" a cable. I thought building one would be a good little project but...too much pain and no gain.

AGENT 86

I built my cable using the diagram below. I stuffed all the parts into the serial connector and it works great with datamaster and Craig moates software. Forget winaldl unless your pre 86.
Data line "E"

Bill-35thAnvrsy-88

Now this will do!! Great schematic!!! Thanks a ton everyone! I'm gonna get on this cable today!

Bill-35thAnvrsy-88

Agent 86...

On the RS-232, It looks like pins 7/8 are looped together as well as pins 1,4 and 6. Is this correct? This would mean the DTR is active resulting in a true Data Carrier Detect and a Data Signal Ready for pins 1,4 and 6 and of course pins 7/8 means that data is ready to send and it is clear to send. So, it sounds like to me, these pins would be looped together. Correct?

Thanks!
Bill

Topless87

That schematic is the 2-transistor I spoke of in my post up above. I only hooked up pins 2,3,5 and it worked fine with winaldl and with datamaster, but I switched to a permanently wired in adapter for the AKM design with a max232 chip.

The +/- 12 volts needs to come from elsewhere, like the cigarette lighter or your harness, and you also need to gound to pin A. Don't use pin A as as your only ground.

Bill-35thAnvrsy-88

Got ya...and thanks again!

Bill

Casethecorvetteman

Do you happen to have one of these for a 94 as well as a list of the pieces i need? Thanks in advance

AGENT 86

I built it as pictured I took my 12 volts from a cig lighter adapter but will eventually bring 12 volts to the aldl to feed cable and use when powering fuel pump through terminal "G".

Stingraynut

I have an 88 that I have been trying to scan for 3 years!!!

A friend who scans a lot of vette's made the cable for me, we've tested using different laptops and different cables -that work on other vette's - all with no result - I bought another ECM which I fitted 2 weeks ago - and still no signal!!!

I'm using WinALDL.

Agent 96, you said why is that? what do you know? Any suggestions would be most helpful.

S'nut

(and thanks Casey for pointing out this thread)

Casethecorvetteman

No worries mate

AGENT 86

I first started with winaldl and then tried Moates and datamaster. After trying all 3, i would have to say the later 2 are just better in displaying, graphing and understanding. I'm just a rookie, but thats my observation
What cable and what program were you unable to make work.

Stingraynut

Hi Agent 86, I'm trying to use Win ALDL. The cable is 3 pins for the ALDL and a serial plug for the laptop - there is a 10k reisistor across AB in the plug.

The cable has worked on another vette. We have tried using another laptop and cable that are verified working on another vette - I think there's something strange about the 88, which is why I posted here - not trying to hijack the thread, but I'm interested in what results Bill-35thAnvrsy-88 has.

S'nut

pcolt94

I built the 2 transistor which works but did not connect any of the extra pins. I don't understand the loop back configeration but will reasearch it. Only the top transistor is used to receive data. The bottom is for transmitt or to program and the free software does not do that. Here are some links for the build.

http://www.obd1.com/

http://www.moates.net/gmecm/software.html