jeepguy553

...piece of turd...
Does anyone have a decent pinout diagram of an OBD-I ALDL port? I thought mine was right, but it appears that it may be missing a pin or two. The harness was butchered pretty badly when I got it and I can't believe it actually works as it is.
Please PM/email me if you have a pinout of the OBD-I ALDL port.
TIA...

JP84Z430HP

The pinout varies by application. Not all the pins are used on any apllication that I've seen. The main thing you'll need to be concerned with is which pin of the ALDL datastream connection is on. I'll look to see what I can find, but I'm sure that someone else will chime in with what you need.

What ECM, mask, and harness are you running?

Bill usn-1

I'm not sure what you are looking for. You only need 2 wires. A8 for the serial data(org) and a grd.
How is the ALDL causing problems. Hell I don't even use the connector. I just put female spades on the 2 wires and male spades on my ALDL cable from the laptop.
The only other wire I have used is the wht/blk A9 for diag.

jeepguy553

ECM: 1228746
Mask: $61
A090 definition.
Harness: 1990 Chev Caprice L05 (350 Cop Car...I think)
I cannot get anything to sync up right. It wants to work in Tuner Pro, but the data is crap. It says my Batt volts are 20.05 VDC when I know for a fact that it is at 12.7 with a DVM right on the battery posts.
I have to admit that I kinda built this datastream definition, so it may not be the best, but it kinda works...at least it connects and gets something useful (tells me I have something).
The harness I got for the install was butchered pretty badly when I got it. I pieced it back together with a DVM, a soldering iron, and several wiring diagrams. There is not a pin to be seen on the lower row of the ALDL port. Ports A-F are wired, but there isn't anything on G-L. I know for a fact that there should be at least a Fuel Pump test pin on G. The rest, I really don't know about. I wired it up hoping that all I would need were pins A-F. I found the fuel pump conxn, but it was actually terminated with a shroud...OEM type...and looked like it was right. Now I can't really get any useful data.

Bill usn-1

So what your saying is the aldl connector is not the problem!!
You have a data stream problem out of the ecmor you are not interpreting it correctly.
Have you just tried to use the winaldl program to verify the ecm is right then work out your data stream problem?

Pin A, B, E should be all you need.

jeepguy553

Yes. I tried WinALDL and got exactly squat. It didn't even connect. TunerPro will connect and gather data. I can't help but think there is something that isn't wired right.
Doesn't the ALDL port have a GND conxn that has to have a good chassis ground or the like?

Bill usn-1

I sometimes get interference if I have my inverter running and the laptop plugged in while I'm logging data. It will go from a green 20 to a red 2-5. So the result is no data.
I have seen where the blk/wht gnd can be run to the ECM case and help prevent the interference. I just turn off the inverter and run off the battery.

If you have traced these 3 wires back to the ecm then I don't think the wires are your problem.
Is your gnd wire tied all the way back to the block with the rest of the system gnds?

If you can't get winaldl to work then I don't think tunerpro will be reliable.
pins

[IMG]ftp://ftp.diy-efi.org/pub/gmecm/manuals/1227747/747ecm7.jpg[/IMG]

jeepguy553

I may have just found the problem. From that diagram, the A12 needs to be tied to GND. The ALDL port is grounded, but I would be willing to lay good odds that the wire coming off A12 isn't grounded. That is waht I needed to see. Too bad it's now midnight and I don't have a light in the garage yet. I'd be outside fixing it right now so I can get some good datalogs.
It'll be fixed tomorrow.
Thanks again, Bill....