I have the blm locker definition file for tunercat and was wondering if it is used just to help tune the AFR @ WOT or can I run it all the time with my current tune? Will there be any negitive effects?

 

I use that blocker all the time, but your question is a good one.

The difference was that if your PCM was adding fuel when it went into WOT, it wouldn't go to 128 and made the tuning more difficult for adding fuel for WOT, and if it was taking fuel out when it went to WOT, then it would go to 128. So, depending on how you were driving and how it was running before going WOT, your tune could be richer than you want, not necessarily a bad thing - safe - but not necessarily the best for performance and made it hard to tune since it was changing.

In my case, the MAF is way over its limit anyway and I have a healthy engine with decent fuel trims, so I just leave the blocker active and tune WOT based on adding fuel to a neutral trim. I have a wideband, etc, and usually tune at the track or make a couple bonzai runs locally and log the results. But for a NA car away from the track, I couldn't see how there would be much benefit to having the blm locker active unless you are doing some street racing for money.

 

I am having trouble tuning my AFR @ WOT, I do have a wideband and have been adjusting the "%change to AFR @ WOT Vs RPM" and by my calculations I should be around 12.8 AFR, I do see on the datalog that the BLM's and integrator's do go to 128 while @ WOT but my wideband indicates 10.0 to 11.5 during WOT.

I think the PCM is adding fuel, I have adjusted my MAF tables but do not know how much they effect WOT fueling. What other tables effect WOT fueling? and what kind of benefit would I see If I changed "MAP threshold to enable WOT"?

 

Maybe you should set your WOT temp cells to 16 for like 80 - 104 and see if that helps make it more consistent - maybe you are having temp fluctuations and it is changing your fueling. The threshold for going into WOT just dictates when your engine goes into fuel enrichment. I wouldn't mess with your MAF sensor calibrations unless you are making minor driveability adjustments and cannot get the BLMs to center close to 128, and only after getting your injector constants and offsets correctly adjusted.

 

Which injector offsets should I adjust?

 

The offsets are turn on time adjustments - really only important for idle where you have small pulsewidths. That information is usually supplied by the injector manufacturer. Usually you only really need to adjust the ones around 12-14V, but it's nice if you have the other ones too, just in case.

 

I use the blm locker on a 97ss OBD2 pcm.
I'm a FI app, so, MAF is over threshold frequency due to the blower volumn.
It has been said (by Christian?) that the GM OBD2 pcm will allow the BLM to be changed to lower injector open time when the MAF high freq threshold is exceeded.
Thus the blm locker. I use LT1 edit version 2.2.
I also use a LT1_edit MAF high threshold set function. Approx 70K over the 10.7k stock calibration.
Hope this helps. B.