BLM- Long term fuel trim?
What does BLM represent? I have a 1989 Chev K1500 350 with a 1227747 ASDU computer. I have both the TunerPro Rt program and the WIN ALDL program. I am trying to find out why my engine will not run correctly when the alternator is charging? I can unplug the single signal wire to the alternator and the engine will smooth out. When the wire is plugged in the motor will go down when accelerating and continues to surge. The tuner program shows a fault [in red] 155 BLM long term fuel trim? When running at less than 12V the number is 128 BLM. If I stay in the throttle long enough the INT fuel trim will go red also? Any help will be appreciated. Thanks G.S.
Still working to learn a new laptop and the TunerPro RT program.
Quote:
Originally Posted by
EagleMark
All good advice above...
But your issue is not the altenator or charging system. You just found a way to make BLM/Long Term Fuel Trim come to the number you wanted. It's probably loosing enough voltage to go Open Loop, so no O2 sensor feedback? Which would always be 128.
You have TunerPro RT, so no reason to do data logs with ancient technology, WinALDL is like data in brale... get your ADX file and learn to data log with TunerPro. I know it's a little harder to get going but the results are well worth it and we can take a look at what your problem is.
155 BLM is adding a lot of fuel. One thing this ECM can not do and does not know, it expects to be correct is fuel pressure. So you will need to check fuel pressure as well.
Is the motor stock? Any mods done please list them.
The motor is stock 350, good compression 170# all cycl. I have had a lot of trouble since Aug 2013. I thought I had a previous post on this forum concerning this truck. I thought I had finally got the engine running correctly then this happened. I really didn't want to drop another $500.00 in a laptop to figure this thing out let alone learn how to use this computer at 76 years old. As you know the manufactors do not supply you with a manual on how to use their products. I need something I can hold in my hand and read. In short the original problem was; it would not rev up in closed loop. The problem finally found to be the MAP sensor or so I thought. All the following has been replaced: fuel pump,IAC, ESC,TPS,OXYS,DIST,TEMPS,ECM,EGR,Complete TBI rebuild,Alternator, All grounds checked loosened and retightened. I probably forgot something as it seems I have been under this hood all summer. I will run the TunerProRt some more and try to learn how to use the program. Thanks GS