I have a 1991 buick lesabra it will crank but it dont get no fire wat can bevwrong

Fuel injectors may not be working check power going to injectors with a noid light. Also check fuses may have a blown ignition fuse.

fuel filter changed too?

I see you changed a lot I of things but are you positive that the spark plugs are firing ? Is the fuel pump pumping fuel ? Have you actually tested these things to make sure they are doing what they are supposed to do.

I changed the strianer thats was on the fuel pump

I changed the fuel pump it i hear it wen i crank and some listen for it and it come on

I dont get any fire

Check the main fuses in the fuse box under the hood maybe a blown ignition fuse or some other main fuse.

They all good

What else can make me get no spark

Sorry for not getting back but the only thing I can think of is the timing chain is broken.

Can it be my igtioan swich

Yes it can but that is why you have to do some testing with a test light to eliminate if that is the problem or not the problem. You do not want to just keep throwing parts at it hoping for the best that can get expensive.