I took out a perfectly good factory "as-delivered" ECU from my 1990 SR5 4x4 auto tranny pickup (California emissions) and swapped in a compatable unit I got on Ebay from a 1990 4Runner to check if it was good. The truck seems to run about the same but without the "cold running richness" that I had listed in a previous thread. All of the other functions work as expected and I get no "check engine" light so this is good. Maybe a quirk, maybe not. Aside from the obvious extra sensors associated with the Cal engines that are used to lean the fuel map, are the timing curves and the fuel maps the same in all ECU's for this engine or is there a "magic" ECU from another specific year/model that will plug-n-play with a little boost?
Thanx,
Bud

 

I don't know for sure but I'd imagine that the cali engine was tuned for better emissions add that to removing some of the emmissions stuff that may have been robbing power and you get a better running engine.

 

there isnt really anything different. Maybe in regards to having a EGR and Not....i dont see much difference in tuning.

I am looking into alternatives for the ecu....gotta get the 4runner back up and running so i can work with these tests