I have a 1991 accord lx.It has 220,000 miles,it runs great but the engine light always comes on after about 20 mins.of driving.Ihave checked my temperature gauge and it is not overheating and all my fluids are fine.No oil leaks or anything,but when i turn the car off it always smells like somthings burning.

 

first off, you need to chk the code and post it here.........
secondly open the hood and chk to see if there are any leaks ( oil,, coolant ) ... fluid might be leaking in the exhaust system , burn up thus the smell ,,
if you do not know how to chk the code .. there is a 2 wire blue plug under the right side of the dash by the kick panel,, you need to jump those 2 wires together with a paper clip,, turn the ignition switch on and count the flashes on the instrument cluster

a longer flash = 10
a shorter flash = 1
so basically 1 long 2 short = 12 ...
let the flashes repeat at least 2 -3 times to make sure you got the correct code and only 1 code ,, ecu could be storing more than 1 code

Also you should post this in the general tch help
and on the final note ,, input year and model in your signature so it will always be there ,, should you need future help

 

the code will tell what the problem is. as for the burning smell, the oil filter housing seal went out on my 91 so i was leaking oil on the exhaust.

 

Here's a link to help you get the code, if the service connector has never been used it will be taped to the harness with blue tape.
As far as the burning smell, the oil pressure sending unit above the oil filter is a common problem.