I have an '06 Mazda 3, 4dr. w/40k. I started the car the other morning and it ran for approx. 5-10 sec. while i put the gear selector in reverse. The car then quit. I put the car back in park, turned off the ignition and tried to restart the car. It would not start. It cranked over a couple of times and was dead. So... i replaced the battery and tried again. It will now crank over but will not start. I have no idea where to start. Fuel, electronic ignition...? If anyone has any pointers that would be great, or what/how to check for certain troubleshooting. Another question......if i bought a code reader, would that tell me anything? ....even if the car will not run?

ANY help would be greatly appreciated.....

 

could have skipped timing, but that shouldn't happen at 40k.
A code reader might tell u something, but it's unlikely. i'd search for TSB's

it's possible the theft deterrant system is preventing the start, try an alternate key if u have one. I don't know how it operates to prevent theft (no crank or no start) but it's an easy thing to try.

You can try another battery reset, leave the batt off for 30 sec or more and short the terminals together when the batt is out - just to make sure there's a hard reset.

Other than that there's tons of things that are needed to start properly.

 

There are 3 things a car needs to start, spark, fuel/air, and compression. You can probably eliminate air and fuel because the car has started before, but you could check to see if your fuel pump if working. My understanding is that the fuel pump is located inside the gas tank so it probably won't be an easy thing to either check or replace if it is bad.

I would recommend visiting the ThaiMazda3 site as they have an online maintenance manual and troubleshooting guide. I agree with djs2571 that a code reader might be able to give you the best answer, but continue to check on the electric side of the equation. My money says you are not getting any spark.

 

You ever figure this out? -Wade-