back testing tick by tick problem

Has anyone had the problem where an EA will open and close orders as programed on the open prices only option, but on the tick by tick option it fails and just opens a bunch or orders at the same time? Is there a common reason why this happens? I do have code in it to only have one order open at a time.

Depends on your modeling quality.

If you're opening one order for each tick, then your logic for limiting orders may not be working. It's also possible you are exiting right away, then opening a new position on the next tick. Without seeing the logic, I can't guess as to what the problem is.

There are two ways that I handle it. If I want orders to open only at the first tick of a new bar then I use something like:

datetime lastOpen;

if ( lastOpen != Time[0] ) {
lastOpen = Time[0];
OrderSend(....)
}

Another option is to build a function that counts open orders. If no orders are open, it returns 0 and I do the test for entry logic. IF there are orders, then I do the order exit logic.