From a previous thread,

https://www.thirdgen.org/forums/diy-...r-changes.html

RBob mentioned a particular switch in the $8D code that resets the integrator during AE events.

L8018, b1: INT RESET WHEN Accel Enr IN WORK

Being a hexidecimal ignoramous, I emailed Tunercat to get it added and he did. So I flipped the switch on. All I have to say is WOW! Everytime I think I have the AE just right on this car, I learn about something else and it improves the throttle response even more.

The transition from off idle is even better than I it was before, but the biggest improvement comes during the transitions from part throttle cruise to power enrichment. It's absolutely seamless now- something I could get very good earlier, but annoyingly never quite perfect. It's freaking perfect now.

Any rate, I'm unclear what the mechanism is for this improvement. Despite the INT diving down during AE before this change, the performance of the car was actually very good. It was more of a curiosity watching the INT on the scanner during the AE events, but I had no idea there was so much of a performance improvement waiting for me to flip that switch.

Tunercat guys should e-mail Tunercat for the updated $8D mask and specify you want the update with this switch.

to RBob for letting me know about this feature!

 

After reading this, I dug into Tunerpro RT and found it there as well.
Easiest way to find it is to search for the term RESET, and it shows up as the second entry in $8D using S_AUJP_V4

 

Interesting, I might have to try this today.......

good info, thanks for sharing!

 

I was thinking about this a little more...

If INT is way down during the AE event (say around 110, which is where mine would dive to during AE), then when the AE event ends, it has to bring the integrator back up to 128, thereby leaning out the mixture momentarily.

Maybe during this post-AE leaning, it was compromising the "crisp-ness" of the throttle response a little. By resetting the INT everytime the AE is initialized, it may mitigate the post-AE leaning.

When I look at the scanner, the ECM is resetting the INT back to 128 during throttle transitions, so it's doing what I'm telling it to do.

Any rate, I did the change on my neighbor's '91 Z (also a miniram'd 350). He indicates a nice improvement in throttle response as well.

Also curious to hear if anyone else who tries this actually sees an improvement.

 

well when it stops raining, I'm going to take my car out and do a datalog it.

Then apply the change, and do another datalog to see how it feels.

I'm running a GM Ramjet intake, and am just curious as to what it will do. It just seems lazy below 2k

 

I missed this part of your first post. You are correct in what is occurring. To get good throttle response the AFR needs to go richer then stoich. This in turn causes the INT to drop, which will sometimes bring the BLM down with it.

This negates some of the AE, and worse, causes a sag as the AE runs out.

The other side of this, when the INT is getting reset, is that it creates a condition of richness. Which isn't good for emissions.

And yes, I've found an improvement when using rich AE and having the INT reset when AE is in affect.

RBob.

 

In what I hope damn well better be a totally unrelated story, all my blinkers have stopped working. Always something! I surprised I still have hair on my head.

 

Below 2k is actually
where I saw the most noticeable improvement.

 

The thing is, with this switch off, you end up chasing your tail on AE. The more AE you add the bigger the impact to INT, and thus the more the ECM reacts by pulling fuel out. It ends up like a vicious cycle with the ECM fighting against you. With the switch on, you tell the ECM to ignore AE fuel and you get the exact AE that you put into it.

 

Not necessarily. Can also let AE be lean/lame and let the INT increase. This too can provide a smooth tip-in transition. May need to speed up (decrease delays of) the INTegrator action.

There are MPFI calibrations (stock GM) where this is the way it is set up.

RBob.

 

Very interesting.....

I might just regret selling this car if this wakes it up below 2k lol

 

Jury is still out on this for me, no scientific proof yet via datalogging, but my light throttle issues don't seem to dip to an AFR of 10 so fast or as often over the past few days. There might be something to this AE option check off box!

Then again my be my left brain/right foot compensating, not sure yet.

 

I actually just flipped this bit in my chip tonight. Been fighting a nasty stumble down low.

Pull out onto 4 lane highway just ******* along and car accelerates fine as I gently increase gas...but then all of a sudden WB02 goes to 16:1 and car falls on its face. If I push harder, it wakes back up. Same thing happens as I am cruising and give it gas. Sometimes stumble..sometimes not.

I have a really NASTY spike in my VE down low and I think its VEPhd trying to adjust the VE tables to take up that sag as it happens so much. I just went back to stock VE tables to start over to try to keep them smoother.

I just couldn't figure this out as it was WAY too long for the AE to still be happening after I leveled the throttle out. Car trying to get int back up makes sense.

I'll try it tomorrow. Was debating on driving car or not...now I think I will.