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Matt
Matt, Mechanical Engineer
Category: Mazda
Satisfied Customers: 20608
Experience:  BEng hons Mech engineering, in auto industry 22 years
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My mazda RX8 is not starting i bought a new battery to day

Customer Question

Hi my mazda RX8 is not starting i bought a new battery to day and fitted it, it is turning over but not firing up the starter is turning the engine over OK so a bit unsure because of the engine type can you help please
Submitted: 11 months ago.
Category: Mazda
Expert:  Matt replied 11 months ago.
Hello these engines are very prone to burning out the ignition coils so I'd 1st suggest removing all 4 coils on the top of the engine and look for a whitish burn mark on its underside if you see this then replace the coil /s if this is OK then I'd do some basic checks1st check for spark by removing one of the spark plugs and plug it back into its lead and rest it on the metal of the engine ( DO NOT hold it on place by hand) then have your assistant turn the engine over whilst you watch the plug. It should give a fat blue spark at regular intervals. If not then check that there's power to the coil pack (at the other end of the plug lead) using a meter. If there’s 12V at the pack but no spark then check the ECU power supply (fuse and relay) and also the connections to the crankshaft speed sensor. 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 Also its worth checking that the electric pump that feeds the injectors is working correctly, it should run for a few seconds then switch off when you first turn the ignition on. If you remove the filler cap to the fuel tank and listen inside while your assistant flicks the ignition you should hear it clearlyIf the connections to this are corroded or damaged then the pump could stop at any time. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse, ideally measure the voltage at the pump and check its getting 12V.You should be getting around 3 bar measured at the injector rail check to see if the plugs are getting wet indicating fuel is flowing – if not and the injectors are opening then there’s a problem with the pump or the filter or even the pressure regulator
Expert:  Matt replied 10 months ago.
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