Possible reasons:I'm having a starting problem in my Legend too. It cranks over just fine but it just won't start. My dad seems to think that it's not getting any spark. I'm not sure what to do
Main relay
igniter
engine grounds
injectors
timing belt
fuel pump/filter
air filter
Cam/crank position sensor
Ignition switch
With all that, you really should have somebody who knows how to properly diagnose a "crank but no start" problem, but I'll try to guide you through it.
Step 1. Visually inspect all battery, ground, and vacuum lines all around the engine compartment. Pay special attention to the ground on the thermostat housing (under the throttle body), the ground under the passenger side fuel rail cover, the battery connections, and visually check all the fuses in the fuse box under the hood and in the driver side kick panel. Pull the air filter and make sure it isn't clogged. Also, make sure the check engine light appears on the dash as soon as you turn the ignition key to the on position.
Step 2. Pop the two small rubber caps of the front of the upper timing belt covers (or remove the upper timing belt covers completely) and use a long 19mm socket and a ratchet to manually turn the crankshaft pulley. Are the cam gears moving? Yes (go to step 2) No (replace timing belt and pray you didn't bend the valves)
Step 3. You need an in-line spark tester ($15-20 from Matco, or a good parts store), Remove a coil pack, hook one end to the bottom of the coil pack, and feed the other end down to the spark plug (make sure you have everything connected good). Crank the engine over with the key and watch for the light to illuminate. If you don't have spark coming from the coil packs, you should test (in order) the main relay, the igniter, the ignition switch, and the cam/crank position sensor (see below for testing procedures). If you do have spark, remove the spark plugs and see if they are covered in gas or oil and replace them if necessary. If the spark plugs are covered in oil, you should replace the valve cover gaskets and o-rings.
Main relay testing procedure:
Main Relay schematics1. Remove the main relay.
2. Attach the battery positive to the No. 4 terminal and the battery negative to the No. 8 terminal of the main relay. Then check for continuity between the No. 5 terminal and No. 7 terminal of the main relay.
o If there is continuity, go on to step 3.
o If there is no continuity, replace the relay and retest.
3. Attach the battery positive terminal to the No. 6 terminal and the battery negative terminal to the No. 2 terminal of the main relay. Then check that there is continuity between the No. 1 terminal and No. 3 terminal of the main relay.
o If there is continuity, go on to step 4.
o If there is no continuity, replace the relay and retest.
4. Attach the battery positive terminal to the No. 3 terminal and battery negative terminal to the No. 8 terminal of the main relay. Then check that there is continuity of the main relay. Then check that there is continuity between the No. 5 terminal and No. 7 terminal of the main relay.
o If there is continuity, the relay is OK. If the fuel pump still does not work, go to Main Relay Harness Test.
o If there is no continuity, replace the relay and retest.

Igniter testing procedure
See online service manual: http://www.arnach.net/service/index.php?x=0000&y=1047&z=2690&r=0934
Cam/crank sensor testing procedure (also known as CKY/CYP sensor)


Ignition switch testing procedure
See online service manual: http://www.arnach.net/service/index.php?x=0&y=1019&z=2690&r=0934
Step 4. You need an in-line fuel pressure tester ($100-200 depending on the brand and type of fittings you need). You'll need to make sure the fittings that come with the kit will work with Honda's banjo style fuel fittings. You can test it directly off the top of the fuel filter.
Here's the service procedure from Alldata:
Here's the picture1. Relieve fuel pressure.
2. Remove the service bolt on the fuel filter while holding the banjo bolt with another wrench. Attach the fuel pressure gauge.
3. Start the engine. Measure the fuel pressure with the engine idling and vacuum hose of the pressure regulator disconnected. If the engine will not start turn the ignition switch on, wait for two seconds, turn it off then back on again and read the fuel pressure. Pressure should be: 265 - 314 kPa (2.7 - 3.2 kg/cm2, 38 - 46 psi)
4. Reconnect vacuum hose to the pressure regulator. Pressure should be: 206 - 255 kPa (2.1 - 2.6 kg/cm2, 31 - 37 psi) If the fuel pressure is not as specified, first check the fuel pump. If the pump is OK, check the following:
o If the pressure is higher than specified, inspect for:
o Pinched or clogged fuel return hose or piping.
o Faulty pressure regulator .
o If the pressure is lower than specified, inspect for:
o Clogged fuel filter.
o Faulty pressure regulator.
o Leakage in the fuel line.

Step 5. If you have fuel and spark, it's time to test the fuel injectors. Here's the testing procedure from Alldata.


Step 6. You missed something, start over again.