Ok, so at the dyno today we learn that my ecu is a bitch and will compensate for every change we make with the emanage. The computer will keep the afr at a steady 14.5…and its really good at it.
So i thought up this idea…The ecu uses a 1 wire O 2 sensor, I could measure the voltage at 14.5 afr and then disconnect the o 2 sensor and simulate that voltage. But, how do I simulate the voltage and deal with changes in voltage from the charging system?
Any ideas are greatly apreciated.
The other idea is to disconect the o 2 sensor and force the engine to run in open loop.
no…part throttle tuning
60% throttle and above the car is in open loop
So I unplugged the O2 sensor last night and have driven the car for about 60 miles and the car actuaaly feels better. Part throttle response is waaaaay better.
Ref: High Performance Electronic Project for Cars – Silicon Chip Publications.
This unit is a huge revolution in DIY automotive performance. It gives you the power to completely tune the air/fuel ratio throughout the entire load range, at 128 load points, providing incredible mapping resolution and brilliant drivability. It uses the Handheld Digital Controller – KC5386, so there is no need for a laptop, and it supports both static and real-time mapping. It can be used on 0-5V and 0-12V signals, so it is compatible with all voltage output airflow meters and MAP sensors. It can also be set to work with 0-1V signals, allowing modification of EGO sensor signals. This unit has been extensively tested on a wide range of cars including Subaru Impreza WRX and STi, Nissan 200SX, BMW 735i, Lexus LS400, and Nissan Maxima. Kit supplied with PCB, machined case, and all electronic components. Kit requires the Handheld Digital Controller – KC5386."
Yeah, the OBD2 ecm is going to always do everything to keep the mixture at 14.5 (actually 14.7:1) for idle and part throttle cruising in closed loop. The computer will add or remove fuel to keep it at that ratio. I’m assuming your car is a late model ('96+) with OBD2. You can’t really simulate the front O2 voltage because it bounces back and fourth based on engine speed, throttle position, etc.
Is the closed loop 14.5 really causing a problem though? As long as you have your open loop A/F nailed down for WOT, you should be fine.
Yeah what is the problem with the closed loop A:F being 14.5?? As long as that doesn’t happen at WOT it is fine. All the FI car I tune run at stoich part throttle
sweet computer, my focus does that too…your gonna have to see if you can get a program/flashtool setup like i have (SCT pro-racer package) where you can datalog, make changes, and flash your car all in minates. it sucks how the cheap easy ways wont work on these domestics, this is one point i actually dont hate hondas
Sounds like you won’t have any more issues with going lean at part throttle in boost with the o2 sensor unplugged. As long as the e-manage can compensate enough to get a solid tune on it you’ll be in good shape. I know you said it was only allowing 6ish % adjustment so we’ll see…