2004 nissan altima 2.5 the engine turn over but won/star, i check for spark on ign. coils but there is no spark , also i install a new set of ignition coils , and don/t get any spark Idon/t know what to do. please see if some one may help me .

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.

HERE'S THE LINK FOR THE 2.5 ENGINE,HERE/S THE 3.5 ENGINE.

check the battery in the key and the engine immobiliser for operation

may be you should make a diagnostic and you can do it in a garage or you can do it by yourself if you want to do it by yourself you need some tools and you can find some good ones here: diyobd2.fr

If the engine is turning over,and still no spark,replace the distributor

Have the vehicle scanned again to see what codes you get. Its possibly either mismatch firing order with the coil boots or hairline cracks in one or more of the spark plugs. I'd remove them and closely inspect the ceramic for damage, even the most minute crack can cause an arc. Then there is always the possibility of faulty sensors.

Does the rotor turn? I would check that out. Take the cap off, have someone crank the engine and watch the rotor to see if it's turning. If it does then try a new cap and rotor. If it does not, I would suspect timing belt. Hope this helps, TJ

begin troubleshoot your car to the fuel system, does the fuel goes to fuel rail, check the fuel pressure, does it pressurized? if no pressure check the fuel pump or fuel itslf,check the fuse of injectors and coils, also the coil ground, if all ok, try to remove one spark plug wire and observe the high voltage drop while crunking the engine, if spark is ok and fuel is ok, it engine timing problem, if no spark check ignition system voltage on and grounding, if voltage ok, but no spark, check the crankshop position sensor and camshaft sensor.

What size engine do you have. Your vehicle should have one coil for each spark plug,no? What coil are we speaking of?