My key wont stay on the "on" position when I start it. It goes to "acc" I had this problem like a couple of months ago. It was the contacts on the key cylinder, the mechanic grinded them and put the cylinder back together and it worked fine. my question is, do I have to buy the whole cylinder or could i get one of a similar car and try to fix it?

 

I would just replace the ignition switch. Find a donor car with a working ignition and a key and just replace it.

 

could i get one at a honda dealer?

 

are the internals the same in all the swithches from da9's
?

 

Sounds like the switch, not the tumbler. Any junkyards close by? Two screws on the back of the tumbler hold the switch on.
Just match all of the wiring-I tried to swap an 90 Integra's with my sons 88 Civic-alittle different.

But if your mechanic ground down something on the tumbler then you would need that too-with the matching key.