HP Tuners Noobie, unable to tune VE
10-05-2007, 06:09 PM
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HP Tuners Noobie, unable to tune VE
Ok, I just received my HP Tuners Pro
, and have read many tuning 101 procedures, which say to start with VE tables(LTFT/STFT). But when I disable my MAF( set freq. to 0 and disable ses light for P0101,02,03 ) my truck barely runs at all, just kinda sputters and dies even giving it some gas. Is there something I'm missing? I reset fuel trims and turned fuel trim learn on. I think my stock, or default table is way too lean. I'm installing my WB Sunday, but my stock O2 voltages were at like 200-400. I'm going to try and post up a log. Any direction would be very helpfull, I've read and read, but havent seen this issue addressed. Thanks in advance. ( That is my stock Scan with MAF enabled, I'll log tomorrow with it disabled again and post it )
, and have read many tuning 101 procedures, which say to start with VE tables(LTFT/STFT). But when I disable my MAF( set freq. to 0 and disable ses light for P0101,02,03 ) my truck barely runs at all, just kinda sputters and dies even giving it some gas. Is there something I'm missing? I reset fuel trims and turned fuel trim learn on. I think my stock, or default table is way too lean. I'm installing my WB Sunday, but my stock O2 voltages were at like 200-400. I'm going to try and post up a log. Any direction would be very helpfull, I've read and read, but havent seen this issue addressed. Thanks in advance. ( That is my stock Scan with MAF enabled, I'll log tomorrow with it disabled again and post it )
10-05-2007, 06:22 PM
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Oh, and if there is anyone in the Bakersfield area who would be willing to become a mentor I'm willing and ready to learn. And would also supply the whiskey.
10-05-2007, 08:54 PM
#6
Using the STFT corrections only from the scanner histogram data
This will require you to disable the LTFT process.
Use of this method requires your VE table to be no more than 10% off. If your VE table is beyond this, start with the LTFT method first.
Depending on your model you can either turn the LTFT enable option to “Off” or set the LTFT minimum Engine Coolant Temp (ECT) to its maximum value. Yours you'll need to change the "minimum" over the right hand side of the fuel OL/CL tab. When you are ready to start the scanning process to record the histogram data, use the VCM Controls function to reset the fuel trims.
This will let the VCM run the STFT correction, but no make any LTFT corrections.
The advantage to this is you only have to use the STFT table on the histogram to get your fuel % correction values. You no longer have to do the (+-LTFT %) + (+-STFT %) math or keep track of the LTFT cell number in use.
This will take you about ½ the time to log the STFT, make the corrections to the VE table, then verify the results on the histogram again.
Your corrections to the VE table cells are the +-% STFT error.
Again, a motor is considered well tuned to have STFT values between +- 4%. Not every motor can achieve this though.
Don’t forget to re-enable the LTFT when you are done.
Table Smoothness
As vehicle conditions change the cell in use of the VE table will change. A smooth VE table will help vehicle fueling transitions. A choppy VE table will cause irregular fueling.
When making changes to the VE table, try to modify surrounding cells as well to help preserve the flow of the VE table. It is unlikely for close operating ranges of your engine to vary drastically in volumetric efficiency and thus your table shouldn't either. Transitions over cliffs, ridges, spikes and other erratic data of your VE table can cause less than desirable results.
Good VE Table
Bad VE Table
All from the help file, except the "yours" an bold underline stuff.
This will require you to disable the LTFT process.
Use of this method requires your VE table to be no more than 10% off. If your VE table is beyond this, start with the LTFT method first.
Depending on your model you can either turn the LTFT enable option to “Off” or set the LTFT minimum Engine Coolant Temp (ECT) to its maximum value. Yours you'll need to change the "minimum" over the right hand side of the fuel OL/CL tab. When you are ready to start the scanning process to record the histogram data, use the VCM Controls function to reset the fuel trims.
This will let the VCM run the STFT correction, but no make any LTFT corrections.
The advantage to this is you only have to use the STFT table on the histogram to get your fuel % correction values. You no longer have to do the (+-LTFT %) + (+-STFT %) math or keep track of the LTFT cell number in use.
This will take you about ½ the time to log the STFT, make the corrections to the VE table, then verify the results on the histogram again.
Your corrections to the VE table cells are the +-% STFT error.
Again, a motor is considered well tuned to have STFT values between +- 4%. Not every motor can achieve this though.
Don’t forget to re-enable the LTFT when you are done.
Table Smoothness
As vehicle conditions change the cell in use of the VE table will change. A smooth VE table will help vehicle fueling transitions. A choppy VE table will cause irregular fueling.
When making changes to the VE table, try to modify surrounding cells as well to help preserve the flow of the VE table. It is unlikely for close operating ranges of your engine to vary drastically in volumetric efficiency and thus your table shouldn't either. Transitions over cliffs, ridges, spikes and other erratic data of your VE table can cause less than desirable results.
Good VE Table
Bad VE Table
All from the help file, except the "yours" an bold underline stuff.
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10-05-2007, 09:22 PM
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10-05-2007, 09:30 PM
#9
Mine idled wierd once I start VE tuning, but after a little bit it idles better. Stick with it man, learning to tune is a little frustrating at first, but after you figure things out and ask a ton of questions it gets easier...
Oh, another thing I did was merge the optimum timing table with my High Octane table and smoothed it a couple of times, it gave a decent improvemet for starting timing tunning.
Oh, another thing I did was merge the optimum timing table with my High Octane table and smoothed it a couple of times, it gave a decent improvemet for starting timing tunning.
10-06-2007, 12:02 AM
#10
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Mine idled wierd once I start VE tuning, but after a little bit it idles better. Stick with it man, learning to tune is a little frustrating at first, but after you figure things out and ask a ton of questions it gets easier...
Oh, another thing I did was merge the optimum timing table with my High Octane table and smoothed it a couple of times, it gave a decent improvemet for starting timing tunning.
Oh, another thing I did was merge the optimum timing table with my High Octane table and smoothed it a couple of times, it gave a decent improvemet for starting timing tunning.
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