So I have an EVO 4 that runs perfect yet i cant do anything with it as far as the stock ecu goes. When I plug in my evo 8 ecu it runs crazy rich and sounds like the timing is completly out of whack. I've tried several different roms and even one tuned by Mellon that was specificly for an evo 4 w/ an evo 8 ecu and still the same thing. I have read that it can be done and I have seen it on a friends car with stock cams and everything just like mine but I cant seem to figure out why I'm having this issue. Someone Please Help. I'm running a Walbro with 850cc FIC injectors, HKS Catback and Blitz Air Intake. Those or the only mods to the drivetrain and whatnot. If anyone can help me please out of the goodness of your heart do so. Any help will be greatly appreciated. Thank again.


Nic Money
Okinawa, Japan
080-4061-1739

 

Are u logging timing & AFR? Do have have the proper scaling/latency values for the FIC 850cc?
Why don't u use a 5/6 ECU? It's the most suited for a 4 since you don't have to swap any pins.

 

I chose to go with an 8 because a friend of mine did it and you can tune much better with upgraded bolt ons down the road. I am logging afr and timing. afr showing 8 or less on idle and timing of 7 degrees at idle. however i'm not getting any values for trim and the 2byte load is all kinds of messed up as well. All of the wiring swaps have been done in an extension harness.
the injectors are scaled to manu setting and latency's are as well.

 

7 is normal timing at idle, but 8 AFR is too rich. What about open loop AFR, is it rich too? You either have a faulty o2 sensor, or might have an issue with the wiring swaps. I still recommend that you use a 5/6 ECU, plug & play with no pin swaps needed, it's fully tunable as the 8's.

 

Nevermind guys. I figured it out and now its running perfect. It just so happened to be one of the wires in the extention harness was cut. thanks again for the help.

 

did that wire happen to be a sensor ground wire?? i had that problem when i did my evo 8 ecu in evo 4 swap