1993 Geo Prism



My (hope to be) future son-in-law owned a 93 Geo Prism that broke down in from of our house. I bought it from him for $100 so that he could go out and get another car, and I thought that I could easily get it running. It would crank, but would not start - no current in the spark plug wire even though battery voltage was going to the ignition coil and the ignighter coil. I check all the fuses and the diagnostic book said that it could be the ECM (Engine Control Module.) Finding out that the ignighter coil cost more than a rebuilt distributor, I replaced the Distributor with no effect; and I replaced the ECM with a used one that had been “checked out,” with still no change in the results. I have deduced that there is an input from some sensor that is telling the ECM not to allow any spark to go to the spark plugs. In the mean time, my (hope to be) future son in law must think that I am pathetic. Does anyone have an idea of how to find what the problem is?


Did you try cranking over the engine with the distributer cap off to see if the rotor turns? It could be a broken timing belt, luckily its a non interference engine.


Buy an igniter; if you dare. It will set you back a few hundred bucks. C’mon; show some guts! It’s always the last part you buy that fixes it. Wouldn’t be the first time.


Well, I would hope the last part fixes it… are there people out there that continue to replace parts after the problem’s fixed? If so, I guess they’d be a mechanics dream, eh?


http://www.autozone.com/az/cds/en_us/0900823d/80/19/dc/f6/0900823d8019dcf6/repairInfoPages.htm Click on this link and click on Fig.177. Use the wiring diagram to check the wiring for integrity between the distributor and the ECM (with a digital voltmeter set on ohms). With the engine cranking, check for the cam and crank signal at the ECM (by backprobing).


The igniter on these cars was problematic. If you can test the existing one, you may find that it is the source of the problem.