Spent about two hours today trying to do VE tuning. I followed the guides on here but every time i would paste the data from the histogram and flash the pcm, i drove around some more and the stft's didn't seem to get any closer to 0. They are mostly in the -20 area. I must have went throught the steps at least 6 times without seeing any results. Do i just paste the info into the primary VE table or do i need to do the secondary too? Anything else i might be doing wrong? Thanks

 

When you're tuning your VE tables you need to be in open loop. If fuel trims are active they will screw up your readings.

 

well the guide didn't say to put it into open loop, but i did disable the ltft's

 

What program are you using, and are you using a wideband?

 

hptuners and no wideband

 

Before I had my wideband, I did mine by turning off LTFT's and tuning just by STFT's. Set your LTFT enable Min and MAX ECT to 284 to disable it. Log STFT's in the VE table axis. When your done, copy your STFT histogram, then paste special - Multiply by % - 1/2 into the VE table. Repeat until you get to slightly negative. I believe you just copy the applicable rows from primary VE to secondary VE.


A wideband is a HUGE help when your tuning, and the only way to tune WOT(The most important area). You'll save the money you spend on a wideband on the gas you use chasing your tail on fuel trim tuning.


Just my $.02

 

OK, the VE tuning I'm familiar with uses BEN factors based on commanded vs actual AFR, read from a wideband. I'm not real familiar with non-wideband tuning.

 

Reset your fuel trims after you rescale the VE.

 

i did reset the fuel trims after each time.

 

A few more things I thought of:

Make sure your engine is at normal operating temp (about 192F on mine)

Make sure DFCO is disabled
Check that Cat overtemp protection is disabled
Put a filter on your histogram to plot Commanded AFR >14.6. This will throw out any data where commanded AFR is less than or equal to 14.6. You can get into power enrichment, but this way it won't record it.

You can't be in open loop to tune by fuel trims. Make sure your are in closed loop.