I built a OBD1 ALDL to Serial cable to work on my 89 Iroc. I used the 2 circuit design on this page.
http://www.mafak.com/2008/08/making-...c-to-obd1.html

I'm using TTS Datamaster to datalog. When I test the COM port it says found GM160 ecu or something to that effect, but when I tell it to start logging it says it's having a problem syncing and keeps retrying and never connects. Car is switched to on with the engine off.

What do I need to do make it connect correctly. Does anyone have any schematics that do work correctly. Since that design was made to connect to a van.

Thanks

 

I went back and took the electronics out of the housing and examined them closely. I found that the base of one my transistors had broken right at the transistor. I will pick up one today and see if it works after I replace it.

 

OK, so I got some data finally. I can't get Datamaster to work. It shows that it find the computer when I test the com port, but when I try to log it, Datamaster keeps trying to sync and never does. I used WinALDL and it worked fine. It's not as easy to read as Datamaster though. The only thing that I'm wondering about is, I keep getting a EECC Slow O2 Rich/Lean Flag and a Rich Flag after I go into closed loop. Also to get it to work I had to put a 10k resistor to get it to work for WinALDL. This is supposed to set it to ALDL mode.

This is an 89 IROC-Z TPI L98 vehicle and I have to run the 1227165 ECM type to get anything. I have Datamaster-32 specifically for the Corvette W/Auto or W/Man Trans and F-Car W/Auto or W/Man Trans. As happy as I am that I can get anything, I still wonder why I can't get Datamaster to log anything.

Any suggestions? Also, what is a normal knock count? I have a exhaust leak right where the passenger side manifold meets the pipe from the driver's side. It's pretty much separated. This may cause some false knock. Are there any other programs out there that work well?

Thanks

 

I'm going to build a 1 transistor setup and see it I can get Datamaster to connect properly. I'm a few 10k resistors short. WinALDL is OK, but Datamaster is much better.

 

I'd recommend building an ALDL interface based on a MAX232. The transistor type interfaces don't always work on every laptop.

To log at 8192 with the '7165 ECM need to have a bi-directional ALDL. So a 1 transistor won't work.

Note about the 10K on terminals A&B. That is required to get the 8192 data logging to start. Once running it may (and should) be removed.

The other thing is that the ALDL on the '7165 ECM is not always reliable. Soemtimes it works, sometimes it doesn't, other times it will work for a while then drop out.

RBob.

 

Sweet, instead of working on the 1 transistor, I may pick up the parts for the max232 then.

 

I tried using WinALDL today. I can see data flowing as long as the jumper is on there and it's in ALDL mode, but as soon as I take it off it goes down to 5 lines and doesn't hardly show anything. Any suggestions? One of the reasons I bought this thing was so I could see whats gong on when I drive the car, but I can't drive around in ALDL mode.

I paid $70 for this cable so I'm going to be mad if I can't use it.

Mine also came up with the same flags posted by the OP.