08 Honda civic ex 1.8 won't start green key lite came on then had ignition switch re placed the key lite stopped coming on but car still won't start key light stopped coming on but still noth

not told does engine crank fast. keyed to crank.????
yes / no . if not say that first.
the starter motor in a car is the best battery tester there is. so is starter dead./????????????
the IMMO on 90%of cars cuts fuel dead onlyl.
on the 10% it cuts starter and fuel both dead
many allow engine to run for 1 to10 seconds and stalls
the IMMo can not be hacked, and is its A#1 top designed purpose to do that, to stop thieves dead.
and works. all new cars have it and is mostly now mandated by laws.
this car I think cranks if key is bad. but will not start

all cars came with it new 2 new keys,working
lost the 2nd.?
we spend a huge amount of time here reading users guides to people lost. the manual is free to read.
at any time , im reading yours now google found it is 1second flat and 1st hit.
my posts are for USA cars only, nothing else ever.
unless they beg, LOL
the immo lamp is in the hot cold, fuel gauge port
if the IP cluster
i see a KEY icon there.it says read page 67
so I do.

"This indicator comes on for a few
seconds when you turn the ignition
switch ON (II). It will then go off if
you have inserted a properly-coded
ignition key. If it is not a properly-
coded key, the indicator will blink
and the engine will not start (see
page 81"
shows 2 immo keys and 1 valet key new

"If an improperly- coded key (or other device) is used,
the engine's fuel system is disabled
When you turn the ignition switch to
ON (II), the Immobilizer System
indicator should come on for a few
seconds, then go out. If the indicator
starts to blink, it means the system
does not recognize the coding of the
key. Turn the ignition switch to
LOCK (0), remove the key, reinsert
it, and turn the switch to ON (II)
again."

do not have other immo keys near the ignition switch
just 1 honda immo only, not even other cars IMMO keys.near, (as the manual said) and is true.
or the keys go to a loggerheads war (radio signals clash)

free guide

https://www.manualslib.com/manual/832826/Honda-2003-Civic.html?page=81#manual

run circuit wire is in the wrong place on the start switch

The problem is you need to use OE ( original equipment )
Honda made their cars so that you need to buy from them not a wrecker...The ignition feeds to the computer, So using a screw driver will make life worse...The ignition cylinder is similer to what"s in your front door...

Even with the reprogrammed key's the engine would crank, it might not start but it would crank over so that leave's only one thing, your used ignition switch is bad.

Did you get the key switch checked out ? The dash indicator lights have to be on for the engine to start. So you are not getting power to the dash lights, and probably not to the computer or ignition coil either.

I would have the ignition switch checked, not the key switch but whats behind the key switch. Ignition Switch!

I think you may have a immobilisor problem try the spare key first

Your problem is not descriptive enough. Has it always been like this or just started happening? If it has always been like this, there is a possibility of a faulty lock OR someone has the door lock replaced and in that event, a new one from Honda comes with a new key that is different from the one for the ignition and the trunk and the glove box. Please provide more details.

check the ignition switch do you have allot of keys on your key ring the weight of having too many keys on your key rings will wear out your ignition switch in a short time

U will need to replace the ignition switch, this is not the key cylinder but the actual electrical switch the key cylinder operated. see photo. I noted that on your model Honda the switch comes with a new key cylinder, you can just use the switch and use your old cylinder over or install the new parts together.