Honda Civic 2001 EX (originally from Canada)
For months, the car would suddenly not start. You can hear it trying, but nothing happens. After a rest or a jump from another car, it would start. A friend checked the alternator and said it was fine, checked the battery and added some fluid. It worked for about a month with no problems. Then wouldn't start even when jumped. The mechanic replaced a sensor for some $70. Went to pick up the car, and he said to replace the battery. Replaced the battery, but it won't start. He says it needs another sensor for another $70-90. I've found two sensors that are worth roughly that much: the camshaft sensor and the crankshaft position sensor (TDC). I just want to make sure that once we make this purchase, it'll work. Can anyone confirm from their experience?

 

When it has a problem even when jumped by another car with not starting does the dash do strange things with flickering lights and gauges? If yes then it could be a bad ground wire to the engine or car body. You have to find all of them, clean them and re-attach them.

The car we troubleshot today was like that, it would turn over but never start, plug in an OBD reader and it would suddenly start, which indicates a grounding problem in the car in our case. In our case there was a loose ground wire to the top of the engine near the radiator hoses that ran to the main frame that was not making good contact. After fixing that the car starts fine. If the car is not turning over the engine but the battery seems good and the starter is not an issue then check the big cable from the battery to the car body to the gearbox and make sure that the contact is good and clean to the car, it might be corroded. Unfortunately this cable is under the air box so it's hard to notice where it goes from the battery negative terminal to the body and engine. You can also buy a replacement cable fairly cheaply just make sure the mating contact surface is good.