I replaced the spark plug and ignition coil and now it won't start?

There could be several reasons why your 2002 Altima won't start even though the engine is turning over. Here are some common causes to consider:

1. Fuel system issues: If the fuel pump, fuel filter, or fuel injectors are not functioning properly, then the engine may not be getting enough fuel to start. You can check the fuel pressure and fuel pump relay to see if they are the issue.
2. Ignition system problems: If the spark plugs, ignition coil, or ignition module are not working correctly, then the engine may not be getting the spark it needs to start. You can check the spark plugs and ignition coil to see if they need to be replaced.
3. Battery issues: If the battery is dead or not providing enough power to start the engine, then the engine may not start. Check the battery voltage and connections to make sure they are in good condition.
4. Starter problems: If the starter motor is not working correctly, then the engine may not start. You can check the starter relay and wiring to see if they are the problem.
5. Mechanical issues: If there are any problems with the engine's timing, compression, or other mechanical issues, then the engine may not start. This would require a more in-depth diagnosis by a mechanic.

It's best to have a professional mechanic inspect your car to determine the root cause of the problem and make any necessary repairs.

Did you check for ignition? Spark? Ignition coil? ECU?

Replace spark plugs as they might have been worn and check the specific gravity of the battery checked. The ignition coil also may be causing the problem.

change the ignition pick up coil assembly normally located on the distributor under the rotor on the bottom of the distributor or just replace the distributor

pick up coil or module ?

1. Ignition Switch: Improperly Connected or Faulty Ignition Switch.
2. Battery: Battery Discharged or Faulty or Coroded, Broken, Shorted or Poorly Connected Battery Cable.
3. Solenoid Switch: Starter Solenoid Switch Faulty.
4. Starter Starter Motor Faulty.
5. Wireset: Worn or Damaged Spark Plug Wires.
6. Coil -Ignition-: Faulty Ignition Coil.
7. Distributor Cap: Loose, Cracked or Worn Distributor Cap.
8. Spark Plug: Incorrectly Gapped or Fouled Spark Plug(s).
9. Distributor Cap and Rotor Kit: Loose, Cracked or Worn Distributor Cap.
10. Carburetor: Worn, Faulty or Damaged Carburetor.
11. Fuel Pump Faulty Fuel Pump.

yes possible.

Car not starting or turning over indicates towards multiple possibilities. It can be issue with battery or weak battery. But if battery checks out ok, then it can be starter issue or faulty alternator or problem with low fuel pressure or no spark at spark plugs due to dirty spark plugs or faulty ignition coil or injectors getting cracked or dirty and needs to be cleaned.

To confirm the problem, the basic troubleshooting is required.

Click this link below and follow the troubleshooting:------

http://technoanswers.blogspot.in/2012/02/car-starting-issues.html

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This will help.

Thanks.

Car not starting or turning over indicates towards multiple possibilities. It can be issue with battery or weak battery. But if battery checks out ok, then it can be starter issue or faulty alternator or problem with low fuel pressure or no spark at spark plugs due to dirty spark plugs or faulty ignition coil or injectors getting cracked or dirty and needs to be cleaned.

To confirm the problem, the basic troubleshooting is required.

Click this link below and follow the troubleshooting:------

http://technoanswers.blogspot.in/2012/02/car-starting-issues.html

---------

This will help.
Thanks.

Try switching the ignition coil with the other coil and plug it in and check for spark again. If it works in the other coil location, then you need an ignition coil. Your engine is bad for valve cover gasket leaks which deteriorate the spark plug wires, so if you are going to put in plugs and wires with the new coil, I would recommend replacing the valve cover gasket and spark plug tube seals(included with the valve cover gasket set).

Test at the spark plug if you are getting current there with a cheap spark plug tester, if not, it could be the spark box. ( it used to be an ignition coil on older cars ) double check the computer for codes which may lead to a cam sensor not giving the PCM information.