Ok I have tried everything I could think of but I can't get usable data from my pcm.

the laptop seems to be able to communicate with the PCM but won't retrieve any data... I have tried Freescan, TTS datamaster, tunercat (which BTW the winflash ONLY works on 1990 vehicles), and the free LT1edit programs.

the tunercat software says "invalid responce from PCM" which is probably because my car is a 94 not a 90 but that means it and the PCM spoke. Freescan shows it communicating with the PCM but no data. Datamaster says "no sync with PCM" I have tried adjusting the com port timing like the instructions said but it says the same thing. The test button yields a pass with communication with the PCM. However when I use the ALDL cable test software it says it fails every time

All this makes me think the cable isn't the issue. I have ordered the definition file from tunercat but it said it takes 2 freekin days for me to get it though an email

the laptop I am using is a PIII 450MHz 512Mb ram 6Gb Hdd with windows XP. I am using a home made cable I built using the two transistor method found here

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

I am good at soldering and I have used the exact parts that Tuner Tools said to. I am at a loss

 

My stuff i bought from moates works with Tunercats... but i can get any data loggin software to work...

 

but isn't your car OBD2? Most dedicated logging software is for OBD1 cars I think.

 

There's AutoTap for the OBD-II cars, and that comes with its own cable.

 

I have used the Freescan for a couple of months. Everytime i have to click on it and close it several times. Finally it will go but never the first time. I keep changing the port and retrying it and then it works.

 

IIRC, I usually get that message when the fans and/or the WP coolant temp sensor arent plugged in. When you first try to read the ECM with tunercat, the fans should kick on for about 2-3 seconds

 

The fans are plugged in but don't come on. The temp sensor is plugged in too

I have the definition file now. I installed it and get an error message when I try to read the PCM "Incorrect responce from PCM". I had the correct definition file selected and its with the tunercat software. I don't get it. I have double and triple checked the circuit. I even build another one thinking it was a fluke but get the same exact thing

What settings do I need to do for the com port? I go into device manager and the data bits are set @ 9600 there is no option to set it at 8192. I turned off the buffering also it still won't work.

I am using a cigar adapter for power and gounding the "A" pin. I hook the data wire to pin "M". I am using pin 2 as read pin 3 as transmit and pin 5 as ground on the db9 connector.... am I missing something?

 

Sorry man, that over my head. I just have the prebuilt cable. Has the car ever been tuned previously? Have you ever been able to get comm with the pcm?

 

as far as I know its stock. If I try to do a read with the data line unplugged it says cable failure but if I plug it in it says "incorrect responce". So Im assuming that it is communicating. I can't justify spending 60-100 bucks on a cable I can build for under 10 bucks. I want to see if the cable is at fault or if I can rule it out.

I am thinking about emailing tunercat but before I do I would like to use the power of the board to rule out any stupid things before I bug them, but this is what I would send them.

__________________________________________________ ______________________

To whom this may concern,

Recently I have purchased the definition file $EE and installed it on my computer. I have a 1994 Chevrolet Camaro Z28 with the LT1 and T56. When I try to read the PCM the program churns and churns then comes up with the error "incorrect response from PCM". I have tried both definition files for the heck of it and get the same error... which according to your manual online http://www.tunercat.com/tnr_desc/tnr_manual.pdf that may indicate compatibility issues with my PCM? I find it hard to believe that is the problem though due to the amount of people that has used Tunercat on their 94-97 Camaro.

I have also looked at the FAQ on the website

I have an older DELL laptop P3 450MHz with a serial port
I have disabled the screensaver and power management. I have no virus scanner or internet with the laptop
I have disabled the IR port
The car battery is brand new fully charged
I am in an isolated garage with standard household lighting
I have tried 2 ALDL to PC circuits they both give the same error
The vehicle is stock engine never removed

This probably isn't a tech support email address but because the program gave me an "incorrect response from PCM" error, I want to confirm that it’s not a compatibility issue with my car.

Thank you
__________________________________________________ ________________________

 

For some reason I have to believe this http://www.akmcables.com/aldlif.jpg has to work better than this http://www.home.aone.net.au/~techedge/vehicle/2tran.gif. And since you like to build your own cable, you can get this http://www.akmcables.com/aldlif.jpg in kit form from akmcables.com for as little as $35. Well worth it. Almost everytime someone is having problems with something other than an AKM Cables cable, that is their problem.

 

OBDI conversion

 

When you pick up the phone and say "hello" and you hear static on the other end, are you communicating?

The only way to rule that out is to compare to a known good cable.

The problem clearly has nothing to do with tunercat, since you have the same problem with other programs. (Every other program, no less.)

Hmmm. Cable test software fails every time. I wonder what that could possibly indicate...

Can you justify paying for a cable that you apparently can't build?

 

you are a very angry man arn't you?

if you don't have something nice to say then don't say it at all, or at least re-word it so you arn't talking down to another member jack.

no responce stated a compatibility issue bub the laptop and PCM ARE communicating

ALDL test program is most likely for THEIR cables which may be a different circuit then what I build and if you knew ANYTHING about electronics you would know that an isolated circuit won't have the exact same outputs.

I took plans from the internet who knows if the design works or not but the cable's cost was less then 5 bucks why the hell would I spend 20 times that if there was a chance the cable worked for me?

 

Well Im out of time. I can't wait for the parts from mouser to come in before I go back to school full time, but luckily I finally sold some honda cb900 parts

I had enough so I just ordered a cable from Andrew (AKM)

If I get time next term I will still build a MAX233 cable

 

ME in EE. Design electronics for a living.

The ALDL interface circuit I designed and built worked the first time...

One last bit of advice - playing around with PCM tuning when you haven't a clue about electronics or software can seriously screw your car up.