QuestionQUESTION: My daughter told me her car's engine turns over but will not start.
ANSWER: The first method of attack in this situation is to attempt to determine what sort of issue is causing the engine to not start.
-- Has the check engine lamp been on recently? If so, any stored diagnostic trouble codes will be of prime importance. In most cases, they'll lead you directly to the type of problem that's present. If you're reasonably handy, this would probably be the time to purchase an OBD-II code reader. Ordinarily, I'd send you to a place that will read them for free, but that isn't practical in this situation for obvious reasons. When I work on a car with this issue, I'll check for codes even if the lamp isn't on or hasn't been on just because it's easy to do, but I don't think I'd suggest purchasing a code reader if the lamp hasn't come on-- too much risk of no codes being present.
-- Does the check engine lamp come on when the key is turned to the on position? It should come on just to show that it's functional. If not, the engine control module (ECM) may not be receiving proper power or ground.
-- Check to make sure the camshaft is properly timed with the crankshaft. If the timing belt has stripped or torn, the engine will not run.
-- Do you have spark from the spark plugs (or the coil)? If not, the ECM may not be receiving the signal from the crank sensor to know when to fire which coil.
-- Do you have proper fuel pressure? If you have spark but not fuel pressure, check the fuel pump.
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QUESTION: Got the car to start when I got there. It acted like it was not getting fuel. I pumped the gas and it finally fired off. I checked the codes and the only one I got was the heater circuit on the front 02 sensor is going bad but this should not keep it from starting. Could the fuel pump be going bad? or maybe just some bad gas? It started and ran fine the rest of the day.
AnswerIf the engine cranks normally but for an extended period prior to starting, suspect an issue with the fuel pump bleeding off pressure while the car is off.
If there seems to be a coincidence between warmer temperatures and the engine starting, suspect there may be a small amount of water in the fuel that is freezing (if temperatures are sufficiently cold).
If the engine was cranking slowly, suspect there is a problem with the battery or charging system.
The code is likely caused by a defective oxygen sensor, but I agree that the oxygen sensor issue isn't related to any cold-start issue. The computer isn't yet using oxygen sensor information under these circumstances.
