randman2011
10+ Year Contributor
- 552
- 282
- Feb 26, 2012
-
Indianapolis,
Indiana
Maybe I'm not searching well enough, but I haven't found anyone else describing the issue that I have. I'm tuning the black box ECU in my 98 GSX for Deatschwerks 1000cc injectors after an engine build. Background:
It was running well but would suddenly go insanely lean (35-100:1 AFR on the gauge) and I had a hell of a time finding the problem. It turns out that the Minitimer to USCAR adapters took just enough slack out of the injector harness that the wires were breaking at the injector connector, causing it to intermittently run on three cylinders. I replaced cylinder 3's connector with an USCAR connector without an adapter and it ran perfectly for five miles before I lost cylinder 2. I have now replaced all four connectors and the car runs perfectly. For about 25 minutes.
Deatschwerks provides a flow value of 945cc/min for my four injectors. I put 941 in ECUFlash and it runs fantastically. Until the fuel trims start updating. They are always positive. The longer I drive, the higher they go, maxing out at 12.5%. If I adjust the injector scaling factor down to compensate, the fuel trims will still max out. The car is not running lean and the O2 feedback trim is not overly positive at any given time, but the fuel trims keep rising. What makes it especially confusing is that at WOT (or any open loop operation) the AFR is now rich by whatever percent the scaling factor has been enriched plus the long term trims, pointing the finger at closed loop software. This means that my rock solid cruise is interrupted by bouts of 7.35:1 WOT awfulness. Additionally, the throttle tip-in additions seem to be negatively affected by the adjusted scaling factor, meaning that the longer I drive the car the worse driveability gets.
I can set the scaling factor back to 941 and reset the fuel trims and it runs well again until the trims max out at 12.5%, so I'm now disconnecting the battery twice a week to reset things. I'm completely baffled by this issue. Does anyone know where I can start looking?
Additional info:
Deatschwerks 1000cc High Z injectors (resistor box removed)
LC-2 wideband, narrowband output replaces front O2 signal to ECU
Latest Ceddy ROM. Default settings except injector calibration and periphery bits to disable O2 CELs.
It was running well but would suddenly go insanely lean (35-100:1 AFR on the gauge) and I had a hell of a time finding the problem. It turns out that the Minitimer to USCAR adapters took just enough slack out of the injector harness that the wires were breaking at the injector connector, causing it to intermittently run on three cylinders. I replaced cylinder 3's connector with an USCAR connector without an adapter and it ran perfectly for five miles before I lost cylinder 2. I have now replaced all four connectors and the car runs perfectly. For about 25 minutes.
Deatschwerks provides a flow value of 945cc/min for my four injectors. I put 941 in ECUFlash and it runs fantastically. Until the fuel trims start updating. They are always positive. The longer I drive, the higher they go, maxing out at 12.5%. If I adjust the injector scaling factor down to compensate, the fuel trims will still max out. The car is not running lean and the O2 feedback trim is not overly positive at any given time, but the fuel trims keep rising. What makes it especially confusing is that at WOT (or any open loop operation) the AFR is now rich by whatever percent the scaling factor has been enriched plus the long term trims, pointing the finger at closed loop software. This means that my rock solid cruise is interrupted by bouts of 7.35:1 WOT awfulness. Additionally, the throttle tip-in additions seem to be negatively affected by the adjusted scaling factor, meaning that the longer I drive the car the worse driveability gets.
I can set the scaling factor back to 941 and reset the fuel trims and it runs well again until the trims max out at 12.5%, so I'm now disconnecting the battery twice a week to reset things. I'm completely baffled by this issue. Does anyone know where I can start looking?
Additional info:
Deatschwerks 1000cc High Z injectors (resistor box removed)
LC-2 wideband, narrowband output replaces front O2 signal to ECU
Latest Ceddy ROM. Default settings except injector calibration and periphery bits to disable O2 CELs.