Hi Guys,

I need some help...I have an evo 7 ecu running Tephramod v7 in an evo 4. The car tuned by myself and runs excellent.

The problem I am having is I keep getting check light for rear o2 and o2 heater. I tried to disable it but it keeps coming back. I am using rom 90550701 v7

I am attaching my rom can someone please have a look and let me know what I should change? or can someone make the change for me

Thanks in advance

 

ecu periphery 2 fca set bit 3 to 0 , strange one as 9055 roms never had a rear o2 also if you need to disable the fr heater circuit as evo4 didnt have heated fr o2 sensor set periphery 0 faa bit 14 to 0

 

try this one rear o2 and fr heater circuit off

 

I found that most of the older cars with non-heated 02 sensors have very slow responding sensors or they are completely dead. This causes the fuel trims to max at 25% during the first few minutes of driving or all the time in the case of dead sensors. Nowadays I run them in open loop as a matter of course.

 

Alternatively fit a 4 wire sensor and wire in the heater circuit switched 12v to one heater wire and other heater wire to pin 60

 

Yes, that's the right way to do it, but nobody wants to pay for a new 02 sensor and the work to run the additional wires

 

yep thats another good point

 

Thanks alot guys will try it and let you know