How do i know if my fuel filter is clogged

If you know for a fact the pump is getting power and ground, and nothing is coming out of the line before the filter, then yes the line could be clogged up.

Not clogged to the point the car won't start

Also ---you know if it is dirty, not clogged, because you know
if it has been in the car over 3 or 4 years,right

You just check your maintenance log book

Did you check the fuel pressure before all of this fuel pump replacement? If the fuel filter is old enough to be clogged up, it should have been changed long before replacing a fuel pump unit. Your fuel filter should be changed every 30,000 miles. However, it would have to be TOTALLY clogged up to keep the engine from starting. It would have been causing all kinds of drivability problems LONG before that could happen.

Then, has anybody bothered to check for spark when the engine will not start? Has anyone scanned the onboard computer? (which happens to be in full control of both the fuel system and the ignition system)

You just might be trying to repair the wrong system...

There is no way anyone online can accurately tell you why it will not run without checking the vehicle first....although many uneducated DIYers might GUESS for you...which seems to be just as good as you are already doing....

PROPER DIAGNOSIS REQUIRED!

is the fuel filter clogged?

If the engine won't fire up, but your starter turns over, you may want to check your timing unless you have a check engine light on. If the CEL light is on, have the codes scanned.

If the engine won't turn over with the starter or it clicks, have your battery tested at autozone or advanced auto parts. Replace the battery if it is bad. Else, have your starter tested.

If the engine still won't turn over and the battery and starter are tested fine, you may have a blown fuse, bad ignition switch, or a failed relay.

If the engine fires up but randomly dies and starts back up, you either have a failed sensor, failing fuel pump, clogged fuel filter, bad plugs or wires, or a failing ECU.

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

your terminology is wrong.if it cranks its turning over what you mean is it won`t start(fire up) as you said at the beginning.anyways it sounds like you could have a fuel pump problem that stop working.this happens alot.you should check for spark at the plugs to make sure its not an ignition problem.did you notice a check engine light on when it was running.if so there will be a code in the ecm and may be the cause of your problem.

REPLACE FUEL FILTER AND AIR FILTER, FIRST.IF ENGINE STILL WONT STAY RUNNING COULD BE FAULTY FUEL PUMP.CLOGGED FUEL INJECTORS.

Assuming there's enough fuel in the tank - If the fuel filter is extremely clogged - try starting with the fuel cap off so it won't have work against the vacuum in the fuel tank. Fuel caps have breather holes which can be clogged also. The holes release the vacuum in the tank slowly. If it starts ok then, the problem sits in fuel supply - for example the fuel filter.

Smell the exhaust pipe - if it smells strongly like petrol, most likely it's the ignition system requiring service. (sparkplugs, distributer, sparklines)

Have you checked the fuel pump and fuel filter? The filter might clogged not allowing gas into the engine. The pump might be bad so you're engine won't be getting any gas there either. Both of those are cheap and easy home fixes as well.

Well then if no pressure at fuel rail then go to pump and in line filter as the in line filter might be the main problem but the pump pressure can also be faulty if filter is bad so check it out and let me know how you get on. Ron