OK, so at one point in time, I installed an aftermarket fuel rail with top feed 750cc injectors on my 1JZ, single turbo, running MAP ECU piggybacked on oem ecu. I ended up going back to the old setup (440cc's) on the oem rail because I couldn't get it to run right. I have been pondering giving it another shot this winter. My fuel kit came with a certification that shows the injector latency's. I am wondering how the latency of these injectors compare to OEM injectors, and perhaps if that is the reason why the car wouldn't run right? When I say it wouldn't run right, it seemed as if I just could not tune the fuel table. No matter what I did, it just ran super rich and sounded like a WRX.

Here is a pic of my certification:






I don't think there is a way in the MAP ECU to account for different injector latency. I really need some insight on this, because it's going to determine for me whether I give it another go with this setup, or if I just buy some larger OEM side feed Sards and modify the stock fuel rail for dual end feed and center return.

Thanks!

Keith