So I'm looking at buying a 94 Loyale. It's a 97k 5speed 4wd wagon. After driving the car, I determined it runs like garbage and maybe has something to do with the check engine light on. I was reading instead of using a traditional code reader, you connect or disconnect connectors by the booster and watch an led light on/near the ECM. ...really?

 

My last three were carbed - an 85 and two 87s. Any help would be great. Guy said he'll take $750 but I'm not willing to take a gamble.

there is a procedure to follow and connect the jumpers to read the codes off the LED on the ECU strapped to underside of steering column.

 

Ask if you can do a comp test on cylinders ... may just need tune up stuff like filters plugs leads cap and rotor etc

 

two green plastic connectors in loom just near the ECU in a few models, think you connect once warm, running etc - I forget. Only time I got a LED read it was accurate and fixed, never a trouble again !

For major constant trouble codes, you can just look at the LED. It will sequence through them while the engine idles.

 

The harness connectors do 2 things. 1 set is to go into dealer diagnostic mode which also displays intermittent codes that were stored in memory. The other set is used to clear the memory. There is a sequence of steps in addition to activate these modes. I don't have my fsm handy, and I don't have them memorized.