I replaced the ignition lock cylinder 98 lincoln town car, and the car do not start. what can i do?

The problem is the ignition lock cylinder, and the small clip (switch) which detects the key being inserted. The lock cylinder should be replaced and most like the ignition switch too, but it is located on the right side of the steering column about 10 inches below the lock cylinder. Not an easy repair, but not brain surgery either. I suggest a professional mechanic or at least someone who has done the repair before on another FORD vehicle. Your radio changes stations because of the electrical "noise" caused by the key "clip".

Its just about impossible to bypass. You would need a key that matches the old key chip cut to the new tumblers. Each key has a chip in it that the computer looks for.

Ford vehicles usually have a small hole under the ignition lock cylinder that allows access to the release for the cylinder. I assume Lincoln has a similar setup. Turn the ignition to on and locate the small hole in the steering column trim, use a long thin punch and stick it in the hole depressing the release. You should be able to gently pull the lock cylinder out now.

How can a lock not lock or unlock with a physical key? Maybe the cylinders are frozen? Try squirting a little oil into the locks.
1996 Town Cars have keys and keyless entry. The physical keys are two, an ignition key and a door key. You can't use the door key in the ignition, nor the ignition key in the door. They aren't interchangeable.
The default key code for keyless entry is posted on the right trunk hinge, inside the trunk.

The lock cylinder is probably worn (assuming that you have the right key!) Try wiggling the key while trying to turn it. Try ay other copies that you have. If the key locks the steering you may have to move the steering wheel to get the key to turn.

You Need a New Lock Cylinder.

check ignition fuse and fuse link.if all is good.looks like ignition switch is bad.

Here is how to remove ignition lock:

   Rotate ignition lock cylinder to RUN position. Using a 1/8-inch drift, depress lock cylinder retaining pin through access hole and remove lock cylinder.

Carefully NOTE: the position of the bearing retainer prior to removal.

   Remove blue plastic bearing retainer by inserting a screwdriver or similar tool, with a 90 degree bend on the tip, between bearing retainer and bearing and by prying upward.

   Insert tip of a screwdriver into Double-D slot of bearing, then rotate 90 degrees. Remove bearing.

   Remove lock drive gear. Carefully note relationship of lock drive gear to position of rack teeth.

Here is the installation:
   Position lock drive gear in base of lock cylinder housing in the same position as that noted during removal procedure. The position of lock drive gear is correct if last tooth on drive gear is meshed with last tooth on rack.

   Position bearing retainer in lock cylinder housing. Insert tip of a screwdriver into Double-D slot of bearing, then rotate 90 degrees.

   Press blue plastic bearing retainer into lock cylinder housing. Ensure retainer is in its original position.

   Line up flats of drive gear with flats of washer by pulling down on the column lock actuator.

   Install lock cylinder assembly.

   Check for proper start in PARK and NEUTRAL. Also, check to ensure start circuit cannot be actuated in DRIVE or REVERSE positions and the column is locked in LOCK position.

For convenience, I'm also including a list of other vehicles that these instructions apply:
Ford Contour ‘98–up
F-150 ‘98-up
Ford Crown Victoria ’97-up
Ford Escort 99-up
Ford Excursion ‘00-up
Ford Expedition ‘98–up
Ford Explorer ’98-up
Ford Focus ‘00-up
Ford Mustang ’96-up
Ford Ranger ’98-up
Ford Taurus ’96-up
Ford Windstar ’98-up
Lincoln Continental ’98-up
Lincoln LS ’00-up
Lincoln Mark VIII ’98-up
Lincoln Navigator ’98-up
Lincoln Town Car ’98-up
Mercury Grand Marquis ’97-up
Mercury Mountaineer ’98-up
Mercury Mystique ’98-up
Mercury Sable ’96-up
NOTE: These instructions may apply to more or less vehicles than those listed above. I cannot confirm that these procedures work for every year and model listed. See your dealer if to confirm this.
On-Board Programming Method "B" for Ford keys (1996 -early 1998 Ford, Lincoln, Mercury)
If you want to initiate a new master key.... 1. Insert new key into ignition cylinder and turn it to the ON (RUN) position. The security light on the dash will flash for fifteen minutes.
2. When the security light stops flashing, you have FIVE minutes to start the next step. Turn the ignition cylinder OFF and then back to the ON (RUN) position. The security light on the dash will flash for fifteen more minutes.
3. When the security light stops flashing, you have FIVE minutes to start the next step. Turn the ignition cylinder to OFF and then back ON (RUN) position. The dash will flash for fifteen more minutes.
4. After the security light stops flashing the third time, the new key has been programmed into the vehicles computer and will operate the car. It has replaced ALL the previous electronic key codes and is the ONLY key programmed into the vehicles computer.
If you want to add a key.... 1. Insert an existing key into the ignition cylinder.
2. Turn the ignition cylinder to ON (RUN) and back to OFF.
3. Remove the existing key and, within 15 seconds, insert the new key and turn it to ON (RUN).
4. The security light will light up for two seconds to indicate success in programming the key into the vehicle.
5. Don't attempt to start the vehicle with any key for at least 1 minute.
On-Board Programming Method "C" for Ford keys (Later 1998-newer Ford, Lincoln, Mercury)
If you want to initiate a new master key.... 1. This requires that the vehicle be connected to special dealer equipment. There are two ten minute delays involved while this device erases all existing key programming and sets up the vehicle computer to accept new key codes. Two new keys should be ready because the system requires a minimum of two keys in the program. After the first two keys are programmed, additional keys can be entered individually by following the instructions for adding duplicate keys (below).
If you want to add a key.... **You must have two original keys to perform this procedure. If you only have one key, you WILL have to take it to the dealer to get it programmed**
1. Insert and existing (working) key into the ignition cylinder.
2. Turn the ignition cylinder ON (RUN) and back to OFF. Ignition should stay on for at least ONE SECOND.
3. Remove the existing key and, within TEN seconds, insert a second working key and turn it to ON (RUN) and the back OFF. Ignition must be in ON for at least ONE second, but no more than TEN seconds. Remove the key.
4. Insert the new key before TWENTY seconds have elapsed and turn it to ON (RUN). Leave it the ON position for at least ONE second and turn back to OFF.
5. The security light will light up for THREE seconds to indicate that the new key has been successfully programmed.
6. To program additional keys, repeat steps 1 through 5
As a precautionary measure for all of the above procedures, you should wait at least one minute after you have performed this until you start your vehicle.

shouldn't have to... just remove the cowling surrounding the steering column between the steering wheel and the dash to give you access to the part