So I bought a used 2005 Mitsubishi Outlander to fix for my girlfriend, before we could tow it, somebody stole battery and cut up the insulation on negative terminal wire. The owner said the timing belt snapped while driving and yes it is an interference engine so hopefully soon I can do a compression test and leak down, but if anybody has experience to help pin point the problem to save trouble it would be appreciated. First, THE CAR IS IN TIME after replacing both timing belts. When I try to start it, it has no sound of turning over like a normal engine it just makes a whirring sound like just the starter is spinning, however all the belts are spinning. At first I suspected bent valves or something near them from timing belt, which is still probable, but after a lot of research it could be a lot. After trying to start and letting it sit for a couple of minutes, when you try to start again it makes a loud popping sound from engine not exhaust, so maybe one or more cylinders is still compressing and when the valves open the uncombusted air shoots out? Head gasket is almost out of the question, but a compression test would help know for sure. Any thoughts?
I put electrical tape around negative wire (yes it’s not a fix but no damage happened to wires and should be good to start car.
By “all the belts are spinning” do you mean the belts outside the engine like serpentine belt, air conditioner belt, alternator belt, power steering pump belt, etc. are moving when you try to start the engine?
If so, the starter motor IS turning over the engine. If it doesn’t start, you have a fuel or spark or timing problem. You seem to be describing an engine that is turning over faster than usual. That points to valves and timing: the valves are not closing all the way, so there is no compression, so the starter motor easily turns the engine very fast. The loud popping also indicates fuel is present but spark is not well timed, so you get sporadic burning of fuel.
Thank you that helped a lot, I’ll test the spark plugs and coil packs etc. But unfortunately i think my first thought was correct bent valves 
If you don’t have advice for repair please don’t comment.
I’ll go ahead and do the compression test and check the spark thank you
And yes the timing and serpentine are spinning
Good luck and best wishes.
Oh yeah one last thing I forgot, the sensor towards front of car on throttle body has a non stop high pitch buzz
This is the order you should do things, in my opinion
spark check
compression check . . . wet and dry
cylinder leakdown test
I suspect you’ll have extremely low or no compression on some cylinders
And you’ll probably have massive leakdown on those cylinders with low/no compression
It seems sort of pointless to spend time doing anything other than a compression test at this point. If the compression test checks out ok, then move on to the other tests. If I was presented with an engine where the timing belt had just broke, I wouldn’t be cranking the engine as the first step. It’s possible when the timing belt broke the valves didn’t get damaged, but later cranking could go ahead and damage them anyway. But it sounds like that bridge has already been crossed. If so, a compression test on all cylinders is what I’d do next.
The first thing that I would do is, recheck those timing marks for the timing belt.
They have to be aligned perfectly. If not your valves could be slightly open during the compression stroke.
This would make for no compression and the engine would spin more freely.
Yosemite
i know this is a year old but my 07 cts is doing the exact same thing. exact. but, i had my cylinder valves fixed so it cant be that.
Were they seated and is the car running or won’t start? Could be a blown head gasket
Try turning it 180% u might not be on compression stroke 
Thank you for responding, I forgot to finish this and post the fix. Yes, it was indeed all 4 intake valves hitting the pistons, ruined the valves but barely did anything except a kiss mark on pistons. Ended up just replacing the cylinder head, head bolts, all the gaskets, etc. Started up the first try with absolutely no problems and girlfriend has been driving it for a while now. Thank you all for your help and hope this thread helps others 