Could one of you fine gentleman please explain the difference between "open loop" and "closed loop" ? My mechanic said that my car won't go into open loop so it'll pass inspection because the OBD Readiness monitors of the fuel system, catalyst, and o2 sensors "aren't ready ? What has to be done to get the car to go into open loop ? Thanks !
The easiest way to explain open loop operation versus closes loop operation goes like this...Originally Posted by MichaelDesna
In open loop operation, which is normally when the engine is first started after a cold soak overnight or after sitting for several hours, the PCM ignores the oxygen sensors while they are warming up in the exhuast stream. The PCM uses inputs from the MAP, Coolant Temp Sensor and the Intake Air Temp sensor, to name a few, to calculate the fuel control becuase the oxygen sensors do not provide good data until they reach a certain temperature.
Closed loop operation occurs when the oxygen sensors reach their normal operating temp and the coolant temp has reached a predetermined setpoint along with some other things. In closed loop the PCM uses the oxygen sensors as direct inputs to control the AFR, or Air Fuel Ration. The varying voltage produced by the oxygen sensors gives the PCM that data so it can give the engine the fuel that it needs based on the current operating condition.
For your PCM to set the OBD Readiness Monitors to ready the PCM will have to go into closed loop operation.
Thanks, Mr. Fast. That was a very helpful explanation.
Should be in closed loop in under 2 minutes, some cheapy bluetooth OBll analyzers can tell you when it happens.
My car stays in open loop and the Readiness Monitors (EVAP, EGR, Catalyst, o2 sensors, and Fuel System) are reading "not ready". It's possible that the car's battery was disconnected when the car was shipped to me two months ago and I don't think I've driven it 40 "drive cycles" yet. Maybe I need to do the Dodge driving cycle to reset everything ? Everything on the tune looks okay according to the original tuner who installed the Whipple supercharger for the previous owner. What do you think ?
Have you followed the advise from this thread? "Help with a scat pack tune..." Tune looks the same.
2018 Trackhawk PCM/TCM tune by Dusterhoff.
Flex Fuel, MMX faux 95mm TB, GripTec 2.85, 10% ATI lower, FIC1200, ARH 1 7/8 w/cats, 180 T-stat
13 Chrysler 300S, RAM BGE 412 stroker, cam motion 232/246 619/619 118 +4, ATI 18% OD pulley
Whipple Gen5 3.0, 2.50 upper pulley, Smooth Boost controller, FIC 1200 inj. Nick W 108mm TB, FORE dual return fuel system, E85, FTI 2800 stall(SRT83380), SHR WAR Viking trans and valve body, Getrag 3.73, 1 7/8 kooks w/hi-flow cats, 3" Magnaflow Cat-back 943rwhp
I also compared my tune to a 2016 stock SRT that a member sent me and it looks the same as that one, too, so I think that the problem may not be in the tune itself. Do you think if I uncheck the MIL boxes under the "Engine Diagnostics" tab for the components that the OBD says "aren't ready" it will cause the Readiness Monitors to read "ready" ?
Reply With Quote