Code 11
 

just put in a new alternator today took a drive after i was done and when i rev my rpm's past 2500 my battery gauge goes up to 18 volts ebrake, tail lights, and battery lights all come on. bad alternator?? its an 87 n/a. throwes a code 11

I think it might just be too powerful. The normal alternators put out 70 amps. They make ones that put out more amps for the people that put like neons or other crazy shite on the car so the battery wouldn't get so much stress.

got the alternator replaced works fine now but the code 11 still comes up and i have no clue what it is. ive looked all over the internet and in my owners manual and the first code starts 12 so if ne knows what it code 11 means please let me know

Code 11 is a momentary interuption in power to the ecu computer

says to check
ignition switch
ignition switch circuit
main relay circuit
main relay
check the ecu

here the page http://www.supra.co.nz/87tsrm/EFI/efi30.htm

something is loosing power ? disconect the ground wire for 2-3 mins and reconect to clear codes and see if it trips the code again? check your batt cables and the main ignition wire off the batt,
check your grounds too some gm cars a code 11 is no codes pressent but i am not sure on this one..

Alternator
 

If your MKIII has a bad alternator the brake light, battery light and rear warning light will all come on so all your litghs coming on is normal. That is it is normal if your alternator is bad. Also make sure you have the right alternator, Toyota change that alternators in mid 1987. And the turbo modle uses a different alternator than the non turbo as does the manual and auto trans.