dr.diesel
06-01-2016, 05:43 PM
Just started on this new project, 1991 2wd Burb with a 454, 4L80E etc. I've been wrenching for 20+ years and mostly a GM guy, but I am somewhat new to TBI ECM tinkering.
Truck has 140K miles, modification history is unknown. What I've done so far:
- New EP241 fuel pump, filter.
- Cleaned up TBI, new pressure regulator spring (factory) and diaphragm, fuel pressure set at 13PSI, reused injectors, visual spray pattern looks fairly conical (I found a yellow regulator spring when I was cleaning up)
- New Distributor, cap, plugs
- Set base timing at 6 DBTDC - with ECM timing connector open
- Removed the RWAL brake controller and bypassed the dump valve - all was defective and set the Parking warning lite. (I mention this just in-case it sets some ECM flag)
The truck runs pretty good, my current goal is a baseline cleanup in preparation for a mild towing 496 build this winter.
Below is a link to the last datalog (ALDL Droid with Red Devil River interface), apologize in advance as it was mostly a errand run and pretty big, but there is one example of a full throttle run, starting at spreadsheet index 16890.
A few questions:
- Why does it appear to stay in Closed loop even when at 100% throttle? My understanding is that TBI setups switch to open loop when above about 70% throttle or so.
- During the same 100% throttle run, any ideas what is causing the lean blip? (WB O2 will get installed when I do the exhaust)
- According to the datalog the torque converter is not being told to lock? This is hard for me to verify as the truck is a 2500, 14FF, no tach, and rides like a log wagon, hard to tell by the seat of the pants.
- I can't seem to find any info on the following columns: Loop Exceeded 6.25mS, Negative Slip Preventing Apply?
- Any other interesting observations from the log file?
https://drive.google.com/open?id=0B7uiVTXpk9fUMW9lWGN1dUNUeEk
Many thanks
Andy
Truck has 140K miles, modification history is unknown. What I've done so far:
- New EP241 fuel pump, filter.
- Cleaned up TBI, new pressure regulator spring (factory) and diaphragm, fuel pressure set at 13PSI, reused injectors, visual spray pattern looks fairly conical (I found a yellow regulator spring when I was cleaning up)
- New Distributor, cap, plugs
- Set base timing at 6 DBTDC - with ECM timing connector open
- Removed the RWAL brake controller and bypassed the dump valve - all was defective and set the Parking warning lite. (I mention this just in-case it sets some ECM flag)
The truck runs pretty good, my current goal is a baseline cleanup in preparation for a mild towing 496 build this winter.
Below is a link to the last datalog (ALDL Droid with Red Devil River interface), apologize in advance as it was mostly a errand run and pretty big, but there is one example of a full throttle run, starting at spreadsheet index 16890.
A few questions:
- Why does it appear to stay in Closed loop even when at 100% throttle? My understanding is that TBI setups switch to open loop when above about 70% throttle or so.
- During the same 100% throttle run, any ideas what is causing the lean blip? (WB O2 will get installed when I do the exhaust)
- According to the datalog the torque converter is not being told to lock? This is hard for me to verify as the truck is a 2500, 14FF, no tach, and rides like a log wagon, hard to tell by the seat of the pants.
- I can't seem to find any info on the following columns: Loop Exceeded 6.25mS, Negative Slip Preventing Apply?
- Any other interesting observations from the log file?
https://drive.google.com/open?id=0B7uiVTXpk9fUMW9lWGN1dUNUeEk
Many thanks
Andy