We have a '91 that has started faithfully until a few days ago, when it suddenly wouldn't start. We've switched out the battery, and I have checked the ECU/ECM for error codes but nothing is showing up as wrong.

The car acts like it wants to start, cranks but won't kick on. Got ideas on what else could be going on?

Would it help diagnose the problem (pinpointing it as a starter or ignition problem) if we try to roll start it?

 

This type of problem typically results from a problem with the fuel system (main relay/fuel pump/fuel filter) or ignition system (coil or igniter in the distributor).

Start by turning the ignition switch to ON without cranking the engine. Do you hear the low humming sound of the fuel pump located under the rear seat? If so, then test whether you have spark at the plugs. This is done by pulling one of the plug wires, putting a spark plug in the end of it, grounding the plug against a metallic part of the engine (e.g., valve cover), and cranking the engine. Do you see any sparking at the end of the plug? ****Avoid electrical shock -- wear rubber gloves when holding the plug wire.****

 

If the starter is turning it over at normal speed, it's not going to roll start either. Do the tests that Ron described.