Intermittent Ignition Timing Problem - 1989 Honda Civic

From a cold start, my '89 Civic starts and runs just fine - on a short trip. If I shut it off for 15 minutes and let it sit, then try to restart it, it cranks REALLY slow, misfires and won’t start (like the cylinders are fighting each other). The battery’s brand new, with plenty of juice. So the next time it happened, I disconnected all 4 plug wires - it cranked nice and fast, no resistance. This leads me to believe that the ignition timing is getting messed up once the engine warms up. I think the coil is fine, because the plugs are firing when the wires are connected. I’m thinking it could be a bad sensor that acts up when it gets warm. My prime suspect is the TDC/Crank Sensor. Does anyone know if the TDC/Crank Sensor can fail when warm? I’m open to any other possibilities anyone might have.


It looks like you’ve done an excellent diagnostic job! From what you say, I’d have to agree, the spark for some reason isn’t firing at the right time in the compression cycle. Likely it is firing too early. Which sensor is broken depends on which sensors your car uses. On a 89 I’d first suspect a sensor in the dizzy.

Maybe the starter motor is getting heat soak which can cause a hard to turn over engine and a lurching sensation. It can be similar to an engine in which the timing is too far advanced.

The reason why it does this with the plug wires connected is because the cylinder pressures are different between an inert cylinder and one that is firing. A '89 engine with I assume high miles and wear may have 150 PSI while inert and 1500 when firing.

You might consider having a starter current draw test performed.