Could someone (Lowbux) explain how the EFI works e.g., do the port injectors work at low rpm and the direct cut in at high rpm or do they both work all the time cheers.

 

https://www.import-car.com/toyota-di...-why-not-both/

 

Thanks Lou thats what i was looking for pretty complex system cheers.

 

Sadly that guy doesn't have a clue about D4S except that they're using both direct and port injection. He failed miserably at his homework for this article. He even missed the introduction and said it was the 2007 GS when it was the 2006 IS with the 3.5 liter V-6 2GR-FSE. Fuel pressures are wrong, transition from port and direct isn't a mystery, it's clearly defined. Pretty poorly researched article when SAE has had this tech brief out for many years.

The real story from SAE is attached.

 

Thanks, Lowbux from basic EFI its still a complicated system is this one of the reasons it is hard to tune or is it cracking the encryption cheers.

 

The encryption is tough. Toyota also uses non-standard chips to make it more challenging, or at least they used to. I have a friend who was in that business, an embedded systems engineer who worked for APR Performance and did ECU mods on anything Bosch. He was unable to get any solid documentation on the processors as they were custom Denso chips. It seems the US EPA killed that when they required the ability to update the software, so it got somewhat easier, but before that time in the A80 Supra days, there was no way to crack the factory tune. They burned it into the CPU, and then burned the connections internally so it could not be modified.