Mazda Repair Questions? Ask Mechanics for Answers ASAP
If there is a spark and its still not starting then its likely that the ECU isn't opening the fuel injectors, if the injectors are working you can hear them click - its difficult to hear them with background noise so use a long screwdriver like a stethoscope, placing the handle end in your ear and the metal tip against the body of the injector whilst your assistant turns the engine over.
If you can't hear anything check the ECU power is present by measuring voltage at the fusebox and on its relay socket if OK then check the connections to the crank speed sensor and consider replacing this sensor if the wiring / connections look OK
If the car will start using a squirt of quick/ easi start into the intake then this confirms the problem is lack of fuel
OK there's power to the ECU
and there's engine speed signal
its just not injecting?
in which case there must no load signal into the ECU to generate a fuel injection pulse
this comes from the MAF meter on the intake so check the state of its connection and wiring for damage and corrosion and also try cleaning the sensor element inside by removing itfrom the car and spraying the exposed sensor wires inside the tube with a brakeor switch cleaner - ensure that the cleaner is one of the old fashioned, nonEco type that does not leave a residue
On no accounttouch the sensor wires with anything physical as they are extremely fragile
OK if the injectors are clicking then they're OK mechanically, it just means that the ECU isn't opening them and if the MAF is reading OK then I'd say its time to send the ECU off for repair / testing
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the only other thing to check is to remove the ECU plug and do a continuity test between the injectors and the ecu
this will check out the wiring loom