breakout box lesson learned
I recently purchased a breakout box from ebay for my 93, eec-iv ranger.
The breakout box goes in series with the connector to the computer. It allows easy probing of the signals to and from the computer with a volt meter.
It goes along with the factory service CD that gives specific trouble shooting instructions using the breakout box terminals.
The unit I purchased was only 100$ which was much cheaper than all of the others.
The reason is that I actually had to remove the eec-iv to connect it into the breakout box.
The more expensive units had flexible connectors to the computer plus to the wiring harness.