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Matt
Matt, Engineer
Category: Nissan
Satisfied Customers: 20592
Experience:  BEng hons Mech engineering, worked in auto industry for 22 years on engine, transmission and suspension design
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Altima: Car running fine, all of a sudden it smelled like a

Customer Question

Car running fine, all of a sudden it smelled like a short and now it doesn't start. It cranks over and just studders. Also when the key is in the on position, my radiator fan comes on. Did not do this before...
any help greatly appreciated!!
Submitted: 1 year ago.
Category: Nissan
Expert:  Matt replied 1 year ago.
hello
I'd 1st suggest 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 clearly
If 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