Hi,

My car came with a GEMS ecu thats really old and i want to go to Tephra with SD.
ive tried to change the ecu (since my car is almost stock.) i figured it should work with the standard software in the box, i have managed to remove the immobilizer and it starts.

It starts at 2k RPM's and stays there, the AFR's are okayish for acouple of mins but then it starts dropping to 10's.
I also get a check engine light and these error codes in evoscan;
P0135 Heated Oxygen Sensor Heater Circuit Fault (Front)
P0183 Fuel tank temperature sensor circuit high input
P0403 Exhaust Gas Recirculation (EGR) Control Solenoid Circuit

I got a 2003 evo USDM with a 2005 USDM MR ecu, should work out of the box or am i wrong? i don't really know what to start with so any advice would help out a lot!

I have done a side by side comparison with my GEMS ecu from the manual i dont know if it will help but i am not sure of everything (ignore my comments in swedish in it)
https://docs.google.com/spreadsheet/...=0&output=html

Thanks!

 

You would have to look and see what has been wired into the heater control. Someone might have used it for an alternate input. Is there egr equipment installed on the car? A lot of people think it's stupid and remove it. It's actually a legit way to increase fuel mileage and doesn't change the capability of your engine.

Again fuel temp may have been tossed and a different sensor in place.

 

I had to change the AC and Fuel pump for it to start.
I cant say about the EGR being removed.
Where is the fuel temp sensor located? is it on the passager side of the car under the backseat?

 

Turned off the EGR in the settings, now it stays flat at 14.7 but the idle continues at 2k RPM, still trying

 

Disconnected the MAF and now i get 1.5, before i tried the TPS actuator setting in evoscan and it went down, now it does not do that when the maf is disconnected.
Its whining about front O2 sensors, i guess i have to emulate that with my wideband

 

hm, got it running with Tephra and now the O2 seems okay.
Need to test some more tomorrow, i have one kink that i cant figure out tho is that the fan closest to the turbo runs all the time...

 

Changed to the ETS intake and mac boost valve, it runs okay but i got high idle still 2k, on MLR they said that it was probably a vac leak, is that what i should look for?

 

Always good to do a boost leak test, no matter what.