I hope someone can help review the attached log. It is from EBL.
I've done several wide band learns and the car is running pretty good in open loop. However I have one issue when switching to closed loop. Between 1400 and 1900 RPM she runs real rough when under load (High MAP areas). The car runs fine when accelerating, shifting and at higher rpm levels.
I created this log which was done in Closed Loop, then tried doing a learn in BLM mode, but there are NO adjustments made at the area where the problem is.

I'm seeing the problem around the following time stamps:
5:43
5:54
7:23

Any suggestions? Do more learns in WB mode? Adjust the fuel tables manually? (if so, what do you suggest?)
Why does the problem show up in Closed Loop, but not much at all in Open Loop?
Since the engine is clearly a bit lean at these times, why isn't the learn making any adjustments?

 

To me it looks like it is adjusting, but at that high of a MAP, I'd think you might want to be in PE and locked at 128. Have you moved around your BLM RPM and MAP settings? I also don't see your BLMs locking in PE.

Dunno, maybe I didn't read it right.

 

My PE comes in at 50% throttle. In the areas where I have the problem I am only at 35 to max 40% throttle, so no, its not kicking in.

 

Bump. Any other ideas on this problem?

 

Questions are asked for a reason.
You may know I’m on the wrong track, but I don’t know what you know.

 

Are you referring to BLM - MAP Learn Threshold and BLM - RPM Threshold?
I haven't touched them.

MAP is 20 low 99 high
RPM is 450 Low and 3600 High.

 

Yes that’s what I’m talking about.

if you’ve done a lot of fuel tuning and plan to run closed loop, your BLMs should be very close to 128.
They aren’t.
If you want smooth closed loop I’d be tuning to 128 blms not wideband.
If you want to tune to wideband, I’d run open loop.

Maybe other people see it differently. But that’s my opinion.

what I think your issue is is the blms jumping around in closed loop due to a wideband open loop tune then you’re going to get some bogging or unhappy fueling.

 

I tune to BLMs in closed loop. I tune to wideband in power enrichment.

 

I don't disagree with what you are saying. But as I said in the first post, I tried to do a Closed Loop/BLM Learn, but yet no adjustments were made around the area where the problem is.
There were some minor adjustments at lower MAP areas of the curve, but no adjustments over about 55.

I do want to run Closed Loop, so how do I fix the problem?

 

Once you dialed in BLMs, did you dial in INTs?

if BLMs are 128 across the board but INT is off thwn you’re still not where closed loop wants to be.

If the car has a big window for the BLM cell thresholds and the conditions are different in the cell 128 may be the average but the INTs will show where the learning is trying to go but may not see the conditions long a nough to correct the blms before it relearns the other condition again. That’s some ugly wording i just spat out but hopefully you understand.

also my completely stock car liked the thresholds changed. It made my car smoother. This also depends on how you drive and transmission (shifting style).

 

I'll take a stab at this, but we need more specs on the engine. Also, please check the header settings when you create the dump log/csv file. It is much easier to read when the header is displayed every second of the log.

I've only ever tuned port injection, so I would assume having only aPW is something with TBI? Maybe someone else can speak to the benefit of running async vs sync on TBI, when you would want to do one vs the other, etc.

Your knock counts are constantly running away. No knock sensor? From what I can tell, you may have zeroed out the knock retard. That's fine I guess, but I would recommend fixing the problem.

What are your O2 swing points set to? Prop gains? We need to know this to know what the O2 sensor values should look like in closed loop. Have you every tried changing them? What size injectors, fuel pressure, etc.?

Try running open loop decel. It is an option flag. It will come out of closed loop for the decel high vac condition and re-enter closed loop once you get back on the throttle. From the spot at 5:43, when you get back on it, it goes pig rich into the 10s with a bunch of AE from dmap and dtps. I would venture to guess this is TBI if you are still using MAP AE. Port needs little to zero map AE since there isn't a ton of manifold wetting going on in a port setup. I have seen closed loop decel drag the INT and BLM around and then it is off once you get back on the go pedal.

I'd recommend a lot of WB learns first to get things roughed in and follow it up with some NB learns. Depending on your swing points and the stoich AFR parameter, that will change the AFR the engine runs at and how the corrections are factored into the PW calculation. Short version is higher O2 values will run richer, and lower values will run leaner. You can change the swing of the sensor by tightening the upper and lower terms closer to the mean R/L value. Makes it more forgiving with prop gains as you need less gain to achieve a smaller swing. Another benefit is less AFR swing in closed loop. The sensor responds slowly and nonlinearly, so YMMV depending on where your swing points end up. I like to adjust the swing points to where the engine runs best (generally richer than >450mv) and average the logged WB AFRs in closed loop. That gets set to the stoich AFR which is "in theory" the AFR the engine will run at in closed loop. That ties back in to the VE table. Hope all that makes sense.

 

RJ, thanks for the great response.
Unfortunately you are talking College Physics and I am still learning multiplication. Let me fill in some blanks and then you can guide me a bit more.

The engine is a Pontiac SD4 2.7 liter. Engine from the 1984 Indy Pace Car. Based on the Iron Duke, but different heads, cam, intake
I am using a 2 barrel TBI from an 80's Trans Am.

There is NO Knock Sensor on this engine. It has straight cut timing gear and solid roller lifters. Much too loud for a knock Sensor.

O2 Swing Points? Do you mean the parameter Closed Loop 02 upper/lower Go Into Closed Loop ? Upper 798 Lower 199 And 'Upper/Lower Stay in Closed Loop' 598 / 351. If that is not the one , let me know and I'll check it.

Closed Loop Stoich AFR is 14.7

For the Open Loop Decel Option flag is that Option Word 3 - Bit 5 OpDcl. Currently mine is UNchecked. Should I check this?

I have BPC - BPC vs VAC set to 175 across the board. Let me know if this should changed. (edit added this)

 

The parameters for controlling AFR in closed loop are below. Just search for these in Tunerpro:

INT-rich 02 upper
INT-lean 02 lower
INT-Mean R/L

Changing the stoich AFR does nothing to affect the actual AFR in closed loop (it affects the BLM values as it uses that defined AFR to calibrate the closed loop running against the commanded AFR specified in the open loop AFR vs RPM table). The loop depends on sensor feedback (o2 mv), so by changing those values, you are changing how the engine runs. Raising them has the affect of richening the *average* AFR, while lowering them has the opposite effect. As I mentioned before, I usually tighten the points together since I am not running cats and want the engine to run smooth without drastic AFR swings. I believe best practice is to set swing points where the engine likes it and is smooth, adjust the prop gain so that the INTegrator isn't trying to force cross counts (numerous threads out there about this), and do a bunch of NB/BLM learns. Start with stock values for prop gains or reduce them by whatever the proportional change is between your current BPC and whatever the BPC of the starter bin you used/other closed loop parameters were defined from.

Closed loop operation is tricky and you may want to stick to open loop until you feel like biting the bullet. Open loop tuning can work quite well with the wideband. WB makes tuning acceleration enrichment easy. Easier to tune that when not having to worry about closed loop terms affecting the fueling.

I'll try to stay on top of any replies and get you sorted out.