johnnyr55

iTrader: (3)

hello guys,
i recently completed an evo ecu swap and im having an issue where the car swings into closed loop and back to open loop... constantly... I have tried higher scalings and lower scalings and the problem still occurs.. I have also tried rasing and lower latencies and the same issue occurs.. I am completely stuck and as a consequence on the open loop i get a rich lean sputter on take off and decel into idle.. Everything else works pretty well but idle.... The ecu goes into open loop after being turned on and the afr will stay either rich or lean until i rev the car high enough around 1200 rpm and then the car will go closed and back to open loop.. Cruising is the same it will swing back to open loop and ill run very rich ..... All the sensors are reading in evo scan and scantech... O2 is a lc -1 with analog o2 sensor simulation.. Stock ecu had no problem with closed loop.. O2 sensor feedback is 0 most of idle when its in open loop... Any help would be greatly appreciated.. Thanks

John

lemmonhead

thats weird, maybe the map says to go into closed loop, but your 02 sensor is al funky and not workie right, so the car puts it back into open loop, but the map says hey go back to closed loop you goof, but the 02 sensor says no go to open loop cause im not workie workie.

Jack_of_Trades

iTrader: (17)

The first things to check are the 'open loop load' tables and be sure they aren't set too low (between 80-100 load is common). The next thing would be the front O2 sensor signal. Log it and be sure its giving a voltage at all between .1-.9 volts. If you are in open loop and its running very rich, the O2 signal will stay steady between .6-.9 probably.

There are only a few other variables which "force" the ECU to use the OPEN loop maps:

Coolant temperature- log your coolant temps to be sure the ECU is seeing that the engine is warm enough.

Throttle position- log your TPS to be sure its below the open loop load threshold. Also make sure the 'Open loop Throttle High Load' and 'Open Loop throttle Low Load' are set higher than your idle TPS voltage. Should be set to about 3 volts at the lower RPM points.

Also, I believe the ECU runs in open loop for a specified amount of time during start up as well. I believe its around 30 seconds.

johnnyr55

iTrader: (3)

lol ha thanks for responses.. I logged and all my sensors are working to specs.. coolant 174 to 186 ish , tps is normal at like 13% on idle and o2 sensor is giving 1.0 when running rich in open loop and it cycles between the .1 to .80 range on closed loop... Thats why im confused... Ill try another free air calibration on the sensor as thats the only other thing i can think to do..

side note the open loop load tables all 4 that relate are stock and the values are 3volts and about and 80% and above for the tps values....

Jack_of_Trades

iTrader: (17)

Be sure to check the tables in ECUFlash too. And see if your load seems to fluctuate at all too.

johnnyr55

iTrader: (3)

ok i flashed another evo 8 rom in and it stays in closed loop just fine -- i tried several roms of the same id and none worked like the different id i have now so i assume for now that the wrong rom may have been flashed before i received it?? Ne ways all is working well so --- thanks for the help