Well, it doesn't really matter much now. I got a multimeter and went to get my stall current and the engine wouldn't run. Wire was disconnected, fixed the wire, still didn't run. Might as well get a new engine with sound installed. Usually doesn't cost all that much more than a good decoder anyways. Thanks all for the input.
I would check with Walther's about repairs or replacement of the locomotive. I think Lifelike has a warranty similar to Bachmann's on p2k locomotives. If you are going to get a new one with sound, you might want to just put a non sound decoder in the older one. Generally you don't need sound in every locomotive, just one in a consist is usually enough. If you decoder is rated at .75 amps, I think the can motor in the locomotive is rated at about .5 amps. If you add in lighting packages and sound, you may be close to the limit of the n scale decoder. If your only problem is that the speaker is too big to fit the model, you could get a smaller speaker designed for use in n scale locomotives. As long as the impedance is similar, the speakers should interchange.
If Walther's doesn't do repairs on older p2k locomotives and it is no longer in warranty, don't give up on it. Hook up jumper wires directly from the track to the + & - termonals on the motor and power it up to see if the motor turns. If the motor turns and the locomotive moves under those conditions, you may have a bad circuit board. I think p2k uses a circuit board between the track and the loads, that distributes power to the lighting package and the motor, and also may reduce the voltage for the lighting package. I think the parts are available to replace whatever is burned out or broken.