The diagram shows the 2 trans and the diode get grounded and the ALDL a to RS232 pin5 get grounded too/again????????

Can these all get grounded to the ALDL A to RS232 pin5 connection? If not, where is the optimal place to connect these grounds.

BTW, I made the one trans cble and tried the winALDL but only got partial readings. I wasn't sure if it was correct or not. I'm going to attempt the 2 trans and Craig's dos booted 8.51 on my Compac Armada w/ Win95.

This is some fun stuff just trying to understand. The archive is good but time consuming. I found a couple of questions about this same grounding thing but no answers.

 

After bouncing this off of one of the EE's here at work I was told that the Ground symbol on the A to 5 pins means that's the common ground needed for the 2 trans and diode.

Correct?

 

the ECM, and both transistors and the diode are tied to pin 5 on the DB9. yes a common ground is needed between the ECM and the Laptop. cheers, Bob

btw..built several this style, works great for me.

 

The cable is made but when I went to hook it up to the ALDL on my car the pin letters are in different order.

The 2 trans ALDL says G is the data and the 1 trans ALDL says E is the data.

I'm trying to hook up my 88 IROC 165.
What pin on my ALDL is data and what pin can I use to get the +12VDC shown as F on the 2 trans schematic?

I'm assuming A and B are the same.

 

Searched and found that pin E on my ALDL is definately the data out.
Now which one can be used for the +12VDC?

 

There is no 12V on the aldl but just get an empty slot and put it there.

 

I tapped directly into the ECM at the plugs and skipped the aldl entirely. Was just easier for me since I had to repin to the 749 from the original 165 MAF. I just made the cable about 3 feet long to reach the seat. cheers, Bob

 

This is what I have so far.

I used the cig lighter to get +12vdc.
I'm not sure what hectorsn means by "just get an empty slot and put it there."

Any empty ALDL slot? or any of the other slots w/ pins that isn't being used by either the ground (Pin A) ,data(pin E) or 10ohm res to ground Pin B to pin A)?

With power comming from the cig lighter and hitting 1 (no beep) I get activity on the screen but it ends with a "no link, try again"
This the info I see on the bottom ofany of the linking screens:

Sending responce: 80-56-1-29

Receiving echo responce0,,6,0,0,0,0,0 (different each time)

63-byte datapack (should stop recvg at byte 64 (C/S) when succesful)

1:0 2:0 3:FC 4:FC same......same till 19:FC (sometimes different each time)

cksum: 0/64 (different each time)

Last byte from com port: 29


In the read me info Craig states the 'last byte read' on the lower side of the screen should flicker between '00' and 'FC'. If something else "This could be an indicator that you need a modified hardware interface, one with a +5V signal (through your 7805) to the DSR pin of the COM1 port"

What is the checksum suppose to match too? Should it look like 64/64?

It seems to get a data stream echo and data stream return but no link.


Well like he said it ain't no plug-in-play baby.