How can a check-engine light problem be diagnosed when there is no readout at all on the code reader?
I just bought a 91 LX 5.0 5spd with 150,000 miles. CK engine is on. It runs extremely rich and rough at idle....almost stalling, then sputters or misses if reved.
I found the TPS was disconnected and reconnected it. No big difference.
Bought a code reader at Auto Zone, plugged in to the left firewall connectors, the code-reader light came on solid. When the reader was turned on (with key on and engine off), I heard a click near the mid firewall, the code-reader light turned off and that was all. No flashing codes, nothing. Waited 5 minutes...still nothing. Tried the key on, engine on....same results.
With the motor running, if the code-reader is turned on, there is a drop in rpm, so I think there is some connection. Why can I not get any reading and what do I do next? Could the ecm or the reader be shot?
My plan is to pull and rebuild the motor anyway. It has very low oil pressure and I hate to run it more than I have to...I was hoping to fix the codes BEFORE I pulled the motor.