I thought your initial post didn't make sense and now I know why!
The cable is supposed to be without slack...not guitar string tight...but again no slack. The pulleys are metal. Its still a very good ideal to get some white lithium grease and lube the wire, the pulleys, etc.
Why your initial post didn't make sense.....you didn't mention the window wouldn't go down as you just let out of the bag in your last post. Now that is very important. I know exactly your problem. Your regulator has fouled itself with the cable. You must be off one of the pulleys for starters. There are five pulleys and the main spool at the motor. Three top and two bottom. What happens is that the cable jumps one or two of these creating slack in the cable which then gets spooled over itself at the regulator motor.
The fix:
1. At the bottom of the glass...there are two attachments for the window glass to the cable. Note the original position of the cable relative to the bolt for later reassembly...in other words...is the cable positioned forward or aft the bolt by the retaining washer. NOW...Loosen and remove both fastener assemblies to remove the glass from the car door. This will make it much easier to complete this repair.
2. Now with power to your window switch, find whether going up or going down will provide more slack to the cable while you pull at the cable with your free hand. Gather the newly freed cable to keep it from getting retangled in the regulator spool. Keep working the cable until its untangled at the spool.
3. Ready to put the cable back on all the pulleys. Now again if memory serves me....one end of the cable from the spool/regulator motor goes to the upper forward pulley, down to the lower forward pulley, up to the upper middle pulley, across to the upper aft pulley, down to the lower aft pulley, through a protective sheath, and back to the spool/regulator motor.
4. Now adjust the pulleys so that the cable is without slack.
5. Back to the power window switch. Roll the cable all the way up. Now roll the cable all the way down. Recheck the pulley/cable orientation. If all good move on.
6. Reinsert your window. Hold it mid way and loosely attach the hardware that secures the window to the cable. Leave it just loose enough to slide the window up and down the cable, while still keeping the cable to fastener bolt orientation correct. Slide the window down to the bottom of the door.
7. Your regulator motor should be in the rolled down position. Now roll it up just an inch. Watch the cable travel. Again...the window is not secured to the cable just yet allowing it to remain in the bottom of the door.
8. Now tighten up the fasteners on the glass to secure the window to the cable. Don't overtighten and break your glass. But tight enough to keep the cable from traveling through the fastener.
9. That should be it. Make sure your hardware (i.e. pulleys, tracks, regulator motor) are all tight. Test it and make sure its traveling all the way up and down. The door/window assembly has adjustments for glass height via stops, and glass cant in and out down at the bottom of the door.
Hope that helps,
John M