t5 boost control issue

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t5 boost control issue

Postby s900t8v » Sun Dec 18, 2016 2:37 am

hey guys

have a really strange problem that I cannot for the life of me work out. - this is on my c900 t5.5 8vT.

I updated the software on my t5 ecu to OBD2, its a 16MHz bin and a 16mhz ecu - I did this because adaption is way better with OBD2 and t5 has the ability to adapt fuel and ignition timing on individual cylinders, not just across all 4.. this means it compensates for crappy injectors and hotter cylinders etc better.

so I made sure the boost request, boost bias and PID maps were all identical to my OBD1 version. I am using the same ECU, but now the car overboosts it does not seem like the APC valve is working at all, I have a T7 modded ECU and ensured that I changed the frequencies for the T7 valve on the OBD2 version I hard flashed to my ECU via combiadapter.

anyway I noticed this - between the old and the new


see the old boost bias map is RPM vs throttle position


The new is just RPM

thats the only visible difference.

I dont think the ECU matters as looking at the bin repository there were 16mhz OBD2 ecus, as well as the more common 20Mhz..

do you guys just think I need to use a 20mhz ecu? or is there something else I am missing... I mean I copied all the parameters from my old ecu maps and it used to control boost perfectly,

and yes boost control is ticked in the firmware options..

its very strange!

I will go and load the program onto a 20mhz and see if that works

does anyone know if there were wiring changes or ECU hardware changes between OBD1 and OBD2

84 Trionic 5.5 8v Turbo


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