Did some datalogging (TunerProRT) and my INT came in around 125-128 at an idle. BLM stuck at 132 and didn't move. What does that mean?

 

It means leave it alone actually. BLM is the long term (slow) fuel trim, and there are 16 "Blocks" for the "Block Learn Multiplier" divided among the different RPMs and LV8's in $6E. A BLM of 128 means no fuel correction was needed in that RPM and LV8 region yet. 132 means that 4/128 ths fuel was added (about 2.8%). It was added because the calibration was lean, but closed loop has corrected it back to 14.7 (called stoichiometry). It doesn't mean the engine is running lean (closed loop keeps it at 14.7), it means the calibration was a little lean. 128 =100% in computer speak, 255 = 200% (max).

INT is the Integrator. Integrator is a short term (quick) fuel correction that closed loop uses to shift the calibration towards 14.7 air fuel ratio as read by the O2 sensor. The BLM will "absorb" the Integrator, thus if INT is low, BLM will decrease, and INT will increase until INT is around 128, and BLM is near the needed fuel trim.

BLM values are supposed to be stored on powerdown. Some calibrations have it limited to a minimum of 128 on powerdown, which means the BLM values will be lost if they are below this. This can be edited in the .ecu also if yours doesn't have access to this threshold.
Add new ecu items in the Constants for:
4D8 is Min BLM on Powerdown for normal cells (multiplier 1, offset 0, rows 1, columns 1, element size 1).
4D9 is Max BLM on Powerdown for normal cells (same as above)
4DA is Min BLM on Powerdown for cell 0 (same as above)
4DB is Max BLM on Powerdown for cell 0 (same as above)

Cell 0 is idle if I remember correctly (I'm only 50% sure, it's been a few months).

Enjoy!

 

You have 16 blocks for fuel cells in a 4 x 4 pattern. There is a unique BLM and INT value for each fuel cell. As you data log you should notice that when the fuel cell # changes, the BLM and INT value might make a big jump. The INT is set back to 128 at key off, while the current BLM values are stored at key off, and are picked up again at startup. Also, idle is fuel cell 0.

The stock '89 MAF boundaries for the above 4 x 4 blocks are
for RPM: 900, 1200, 2400
for MAF: 15, 24, 60

So, the 0 fuel cell is for the case where the engine RPM is 900 or less and the MAF flow rate is 15 gms/sec or less.

 

Could you guys help me out? I'm running a custom prom. car has BLM's and int fluctuating in the 124- 134 BLM range when the BLM is 128 the integator will be fluctuationg between 118 and 132, and vise versa for Integator vs. blm's.

the problem is in block cell 15 at part throttle the BLM's go to 112 and stay there, every where else it's pretty clean, but it's rich at part throttle cruise 65-90 mph will stay at 112 in cell 15 using tunercat how do it lean this with out throwing off the other values?

otherwise it's pretty crisp, but mileage suffers with the rich cruise BLM,

and at idle it's at like 150 BLMs and won't richen up,
I know I may have other problems, where to start?

Wide open throttle is 128/128


MAF car with hotcam
24lb svo inj,

52mm TB
full smog
org air diverter valve, everything else has been replaced in the last 2yrs

Please forward this if you know anyone who can help

Thanks

 

No.
The correction is applied to bring the car back to 14.7. If your in closed loop the car's trying to run at 14.7:1. Up until you peg the BL, your at 14.7.

 

Grumpy,

so what you're saying is that at cruise it's at 112 BLM to richen the mixture to hit 14.7 , so in reaity it needs to it's adding fuel to bring it to 14.7?
should I worry about the lean idle? everywhere else the car seems to be pretty good. Doing the old fashioned plug read, the plugs were a nice light tan color with a small light black ring arround the electrode.

Mileage is still a little off, could be something else.

Thanks for your response grumpy, I've been on this board for years and know that you are a expert with this stuff. I just know there is more in my combo once it's tuned well. overall it runs good. but I'm getting arround 12-13 city and 15-16 highway, I know a tpi with a hotcam can get closer to 15+ city and 17-18Hwy that is what I would be happy with. but I am running sub standard California oxygenated gas @ 2.40 a gallon.

any suggestions would be appreciated.

 

Grumpy,

Can you chime in and give me a little direction on how to get my car's tune closer; is my understanding of your reply correct?

any help is appreciated,

thanks