OBD 1 Scanmaster hook up

[spikester7878]

Kinda of a newbie question here but here it goes. I am trying to hook up my scan master but all the instructions I find are for OBD2.

I have the OBD port loose and can access the wires I know I need to use Port A(ground)

Now my question is do I use the diagnostic or serial wire? (port b or port M)

What can I connect into for a good power source?

[Injuneer]

Do you mean the Scanmaster LT1, as in the photo below:

If so, here's the instructions from my Scanmaster guide:

INSTALLATION:

The Scanmaster is supplied with a 4-wire bundle (Note: I have heard that the later models may be missing the green wire). The wires have stripped ends, and that's it - no plug, no connector.

-RED - +12V power supply. It does not have to be "switched" power. The Scanmaster will shut itself down on loss of signal. I used the wire that goes to the cigarette lighter. There is no +12V pin in the 94 OBD-I ALDL connector.

-BLACK - Ground. Connect this wire under any good screw or bolt that is securely mounted to the metal chassis.

-WHITE - Data Wire. Connect to the data terminal in the ALDL connector. In the 94's this is the lower right hand pin. On all models, this is a light tan wire.

-GREEN - not used.

Some thoughts on the wiring details:

-You need to provide a "disconnect" on the white data wire. It must be disconnected if you attempt to attach any other device to the ALDL connector, like a laptop cable for LT1_Edit or other programming system, a cable for a Hypertech Power Programmer, or a dealer scan tool. The Scanmaster uses bi-derectional communication, and the signals from the Scanmaster will interfere with the signals from programmers or other scanner. A small switch or a "plug" will suffice (see pic below).

-If you put a "plug" (connector) in the other lines it allows the unit to be rmoved and used on another vehicle.

-The white wire does not have to be connected directly to the pin on the ALDL connector. I spliced into the tan wire on the back of the ALDL connector.






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[spikester7878]

yup thats what im talking about. How did you hook up the switch? I ended up using the M pin which is the lower right side. I will try hooking into the cig lighter tomorrow. hopefully that will get it working.

[Injuneer]

White wire from Scanmaster attaches to the micro-switch. Other side of the switch is wired to the back of pin M. Switch interrupts the signal to the Scanmaster.

[Jayz28]

Is a scan master really beneficial? I have one that I've never hooked up.

[spikester7878]

alright i got it working. it worked for about 5 minutes. then the display went all 8.8. ect ect. and wouldnt turn off Can I assume the serial wire connection came loose?

[spikester7878]

so far I do like it...well while it was working. It lets you monitor the engine without having a laptop. I pulled the codes off it and theres a ton of setting I need to look up so I know what they are for haha

[Jayz28]

so far I do like it...well while it was working. It lets you monitor the engine without having a laptop. I pulled the codes off it and theres a ton of setting I need to look up so I know what they are for haha

Awesome. I may hook mine up.

[spikester7878]

got it fixed. I have two switches. one from the power supply (cig lighter) that i put in the ash tray, and one from the Serial wire. It no comes up with all 8.8.8.8.8.8.

[Injuneer]

Is a scan master really beneficial? I have one that I've never hooked up.

I bought mine in maybe 1997. After watching the engine run for a couple years, I was able to write a 26-page guide to scanning the LT1. I learned as about how the PCM controls the engine by watching the Scanmaster, as I did by reading manuals. I saw stuff going wrong and fixed it before it became a problem. If you get a tank of bad gas, it's going to be obvious.... the knock retard will pop up. Want to save money by using lower octane fuel - try it, and see if you get knock retard. If you don't get retard, your are fine. How else would you know without a real time indication of what is happening to the engine.

I don't use the stock PCM to control my engine any more - it's running off a MoteC M48Pro engine management system, with built in data logging. I always have the last 20 minutes of engine operation stored in the ECU. But I still keep my Scanmaster hooked up, and paralleled a lot of the inputs to both the stock PCM and the MoTeC, so I could monitor the vital signs without having to have my laptop set up in the passenger seat.