VE Tuning w/o Wideband?
Is it possible to do some rough VE tuning without a wideband? The VE tutorials I've read all require a wideband. I'm trying to dial in my tune at idle just to get this thing to pass smog. Right now it's putting out 36% too much HC at idle, but is 92% under the HC limit at 2500 RPM. It is also misfiring slightly at idle which is probably the issue. I'll get a P0300 after a couple minutes of idling. The misfires are spread out evenly across the cylinders. The tune is stock at the moment.
2001 Silverado 5.3L ECSB 2WD T56:
T76 turbo, Meth injection, 72# injectors, 799 heads, 212/212 114LSA cam, Built 4L80E, 3.42's
EFILive V1 Commercial, COS5 2-bar SOLSD, AEM wideband
Ok, so you have a cam but havent tuned it at all? You NEED a wideband, like go buy one tomorrow. If you mod the engine at all, you need to adjust the VE/MAF tables and Im frankly surprised your engine runs on the stock tune with a cam. You could be super lean at idle which is causing your excessive HC and your misfire.
You can try doing Calc.VE using LTFTs, its ok for a rough (really rough) start.
I apologize if I sound like a jerk, but you really need to get a WBO2 on it asap. You can rough in a VE/MAF table using Calc.VET in a few hours tops, be done with all of it and pass emissions.
~Erik~
2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.
Thanks for the tips. I do have a wideband, but it's not installed yet. I'm hoping to get this thing to pass without spending money and time modding my stock exhaust system or doing in depth tuning. In a couple weeks when the turbo goes on everything will change, hence not wanting to put too much effort into it. The wideband will go on with the turbo.
The cam isn't all that big. It runs great other than the misfire issue. But I do baby it around as I know the stock tune is not ideal.
I'll try and do the Calc.VE using the tutorial.
2001 Silverado 5.3L ECSB 2WD T56:
T76 turbo, Meth injection, 72# injectors, 799 heads, 212/212 114LSA cam, Built 4L80E, 3.42's
EFILive V1 Commercial, COS5 2-bar SOLSD, AEM wideband
If you're getting misfires at idle, you may be overly lean or overly rich...
unburnt fuel means that unburnt oxygen is present, the NBO2 sensors see this as lean, so the PCM keeps adding fuel (too much fuel).
Or there may be other causes of misfire (coolant leak).
At idle, the PCM may be using either of MAF or VE.
Using the scantool->tunetool cursor linking feature can you determine which cells in the various tables are being referenced (B0101, B3605, B5001).
Try changing the O2 mV switch points.
What do you suggest for O2 switch points? The only thing I've read is to set them all to 450 mv.
My O2 activity at idle is not pretty, they appear to be lazy as you have mentioned before. My guess is they are acting lazy because of the misfires.
And what about idle timing? Right now my base table is calling for 18 deg at idle. It varies fairly erratically at idle, from 9 to 24 deg. Tomorrow I may try to add timing using Bidi and see if it helps the misfires. If I fix the timing at idle then it starts to surge +-150 RPM from commanded.
2001 Silverado 5.3L ECSB 2WD T56:
T76 turbo, Meth injection, 72# injectors, 799 heads, 212/212 114LSA cam, Built 4L80E, 3.42's
EFILive V1 Commercial, COS5 2-bar SOLSD, AEM wideband
I understand not wanting to spend a lot of time before turbo'ing, but the solutions is pretty simple: spend the 2-3 hours, Calc.VET it, pass emmissions.
Id do that, then once you have the A/F done you can tweak spark timing at idle.
Sometimes the only way is the way we've been avoiding, you're going to spend more time trying not to tune it than if just tune it and being done with it.
~Erik~
2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.
Possibly, or, the O2 activity may be causing the misfires.Originally Posted by ferocity02
Try timing and see what happens to misfires (good idea), and if you now get surging, the you will need to tune in this area.
More info:
Did one round of CalcVE this morning as a practice. Seems to be working okay. Should I be resetting the LTFT's before starting?
I also messed with the timing at idle and found that reducing the timing for the most part eliminates the idle misfires. My base table calls for 18 deg at idle. Using DVT I subtracted ~10 deg and the misfires went away. It seems to be able to maintain the commanded idle speed better as well, +-20 RPM at the most. Before it was +-50 RPM. The exhaust smells noticeably better too. The idle sounds rougher and deeper with the reduced timing. Any downside to running the idle timing this low? Research shows people running 20-30 deg timing at idle.
2001 Silverado 5.3L ECSB 2WD T56:
T76 turbo, Meth injection, 72# injectors, 799 heads, 212/212 114LSA cam, Built 4L80E, 3.42's
EFILive V1 Commercial, COS5 2-bar SOLSD, AEM wideband
Yes, reset LTFTs between log/tune sessions.
Not sure on idle timing, really more of what your engine likes.
~Erik~
2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.
Ok, I've been reading Calc.VET threads up the wazoo... lots of useful information but I wish it was all in one place for easy reference. Again, I'm doing this without a wideband just to get the VE table roughly close enough to pass smog. Do these steps sound correct, assuming the calc pids and maps have been correctly setup?
Tune mods:
1. B0701: Disable Catalytic Converter Protection
Insures accurate stoich and PE mode/WOT Fueling
During tuning only
2. B0120: Change RPM Threshold for Airflow Calculation from 4000 to 400
Eliminates any Airflow Correction from the VE Table
During tuning only
3. B3308: Disable DFCO: Change B3308 (M6) to 140C Change B3313 to 140C
Accurate fueling computations
During tuning only
4. B4105: O2 Switch-points to 450 Millivolts
Smoother MAF & VE Table
Permanent
5. B3618: PE Modifier Based on Rpm (EQ): 1.16
Safe adequate Fueling regardless of Fuel Type
Permanent
6. B3616: PE Enable: make sure PE enables as load becomes significant
(e.g. below 60% TP below 3200 rpm, 35% TP above 3200 rpm).
Permanent
7. B3608 and B3609: PE Delay: set these to zeros.
Permanent
Logging:
Reset LTFT's before logging
Log data
Filter data to exclude for ECT, low cell count, high TP% change
Adjusting tune:
Copy and paste calculated VE table into B0101
Smooth table
Copy and paste (multiply) calculated LTFTBEN table to B5001
Smooth table
Repeat logging and adjusting tune steps until B0101 and B5001 aren't changing much. Revert tune changes 1-3 back to original values.
2001 Silverado 5.3L ECSB 2WD T56:
T76 turbo, Meth injection, 72# injectors, 799 heads, 212/212 114LSA cam, Built 4L80E, 3.42's
EFILive V1 Commercial, COS5 2-bar SOLSD, AEM wideband
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