Help....hubby was driving 2003 Elantra to lunch yesterday, and car just quit him. Had it towed home, charged battery, checked fuel level....still will not start... tries to turn over but seems like maybe either no fire or not getting fuel....hubby NOT mechanically inclined, just trying to troubleshoot it so our "shadetree mechanic" can get at it as soon as this snowstorm passes us by.....

if starter motor is dead silent?
do as all do, jumper cable jump start it. (try park and neutral)
call AAA auto club, ask for a jump.
or charge the battery (a tool)
or barrow a good battery to try.
or make sure battery cables are not loose nor rusty.
if stranded?, then try neutral trick then call for a tow.
ask dad or hubby (BF) for help or brother or any other car savvy helpers. call the auto club (ins co)

Brake Light. Make sure you are not driving with hand brake on. Check brake-fluid level. Top off brake fluid if low and make appointment to check brakes. Driving with brake light can be dangerous; deal with this soon. Call tow truck or drive carefully and slowly to shop.
ABS (antilock brake system) Light. Indicates either low brake-fluid level, stuck brake caliper or faulty ABS. Check brake fluid and make appointment to get brakes checked. Call tow truck or drive carefully and slowly to shop.
Oil Light. Either engine is very low on oil or there is no oil pressure. Pull over and turn off engine immediately. Check oil level and add oil if low. Turn engine back on to see if light has gone off. If oil light is still on, bad oil pump (no oil pressure) is likely. Call tow truck.
Check Engine Light. Car's computer senses engine problem. Difference in performance may not be noticeable, but make appointment to have car diagnosed. This usually cost around $65-$75 to do. OK to drive. If problem is serious, computer may switch to limp-home (low-power) mode and you won't have option of waiting to bring car into shop.
Air Bag Light. Get air bags checked. Problem could prevent them from activating in accident. OK to drive, but not safe in accident.
Battery Charge Light. Alternator is not charging. OK to drive, but turn off any unneeded electrical devices (radio, heater, defroster) and avoid starting engine more than necessary. Bring car into shop soon to avoid getting stranded. When alternator is not charging, battery loses charge and car stops working.
Emissions Lights (O2 sensor, EGR, check emissions). Depending on car model, these lights may indicate problem with emissions sensor or may light up at certain mileage, usually 60,000 miles (100,000 km). Get sensors checked. OK to drive. If problem exists, car might get poor gas mileage.
OBD Tools 365 Days Shop

it should have a vent hose somewhere that is clogged has far has code goes you can just type it in and your car you should find it on the internet easy

Did you check the oil level? After making sure that oil and water are at proper levels, and BATTERY is fully charged, start it again while checking the fuel pressure at the fuel rail. Also check and make sure vacuum line to fuel pressure regulator is good and hooked up.
If it doesn't start,try it with the MAF unhooked. Sometimes a bad MAF sensor will keep them from starting.
Outside chance of a bad alternator too. don-ohio

Have you checked the alternator, I work at a auto parts store and see this all the time, check the inline fuel filter, also have your checked the coil, mine went out and that was the last thing I checked but am back on the road.

Very likely the fuel pump has failed, if you mean you tapped on the gas tank
and it finally started. When a pump fails, sometimes rapping on the tank will re-energize it briefly or maybe even a couple of times before it gives out for good.
If you were tapping on the gas pedal, though, and it just started, your mechanic will have to look at it. Too many electrical fault possibilities, Scott, it needs proper diagnosis to find the p[roblem.

check the filter! first! it is possible its stopped up! when taking the filter lose start at the rear line and check to see how much pressure comes out? if its little to no! pressure then the fuel pump is weak!

check to make sure you still have fan belts on the car it sounds like you broke a belt or belts

look for sulfate around terminals boil a cattle of water and pour water on top of both terminals slowly, do not touch terminals with your hand or avoid skin contact with Battery and terminals, after battery top is clean wipe of the top and look for caps, remove end caps negative and positive first and look at inside water level on battery, it has to cover the inside metals plates at list 1/2 inch, plates submerged on that water, if water is close or under metal plates level? add on the 12 reservoirs, do not over flood, Use any clean water, than no water, Distilled water is the best to use.
.Check also main fuse or main key wires and connections,
Check grown attached bolt to metal body.
Check connection of Battery Main positive attached starter motor.
Look at Battery exp warranty.

Confirm the condition of your battery then check the ignition switch and power distribution box for any loose connections