Q: I have a nissan Altima 2008 sedan, Yesterday I was almost running empty so I fueled up at Shell gas station. As soon as I pulled o

Inasmuch as the problem started immediately after you bought gasoline, it is possible the gasoline is contaminated. As a preliminary matter, you might call or visit the station and ask if anyone else contacted the station with a similar problem. If the gas is bad, at minimum, the tank will have to be completely drained. Bad gas is speculative but obviously is a possibility because you are stating that this problem happened immediately after filling an empty tank.

If the issue is NOT bad gas, this would be diagnosed as an ordinary no start fault with one departure which is to first check to see if the in tank fuel pump is pressurizing at key "on". Have an assistant turn the key to the "on" position (NOT "start", just "on") while you listen right at the fuel tank. You should hear the momentary "whir" of the fuel pump as it pressurizes the system at the instant the key is turned "on". If you hear nothing, you may have a dead fuel pump.

Check to see if there are any stored diagnostic trouble codes. Be sure you have a fully, 100% charged battery that passes a load test. Confirm that the engine immobilizer system (security system) is not activated thus preventing the car from starting. If the immobilizer system is on, you may see a security warning light. If the warning light is on, to temporarily override the immobilizer system, see these instructions. If the starter motor does work and the engine cranks at adequate RPM, be sure there is adequate fuel pressure, injector operation, and a spark at the spark plugs. Basically, if the starter motor is turning the engine over rapidly, at sufficient RPM, but the engine does not catch and run, that means that there is an ignition, fuel, air induction, or mechanical fault in the engine that will have to be repaired. Strictly speaking, if there is fresh fuel being delivered by the injectors (not just "to" the injectors) and the ignition system is working, that means that the air fuel ratio of the mixture delivered to the cylinders is so far off that the mixture just won’t ignite. Such could be due to a big vacuum leak, an air induction fault like a stuck idle air control valve or, considering fuel, could be due to a failed temperature sensor that must be working properly to signal the PCM to enrich the mixture on cold start. Other common faults are defective spark plugs or a defective coil.

If your circumstance is that there is no starter motor operation at all, that is if there is no starter operation with the key held in the "start" position, the procedure is to test for power and voltage drops to the starter motor/solenoid. If there is no power, or a large voltage drop is measured, then the electrical circuit supplying the motor has a fault. That circuit begins at the battery and includes grounds, wiring (some of which is very heavy cabling), fuses, relays, the ignition switch, neutral start switch, and terminations. Basically, with a fully charged battery, and with the key held in the "start" position, the starter is either getting power or it isn’t. With the key in the "start" position, if the starter motor is getting power but the starter doesn’t work, then the starter is condemned and replaced. Note that starters can and sometimes do develop intermittent faults due to bad spots on the armature. The bottom line is if there is battery voltage to the starter (and no excessive voltage drop) and yet the starter doesn’t work, it’s dead. Regardless of the underlying cause, if you request a no start diagnostic the responding certified mechanic will get the problem diagnosed and repaired for you promptly. Please let us know if you have further concerns or questions as we are always here to help you.