89fast5oh

Age old question that has been covered many times according to my searches. I have read the Prom Burning Guide, and many many threads on the subject. All point to Acceleration Enrichment and LV8 parameters. I understand some of them.

I have a 383 with AFR 195s, Edelbrock ProFlo XT (like a HSR) and Comp XR269HR 218/224*, 700r4 2600 stall 3.23 gears, 30lbs Ford injectors.

WOT, Idle, cruise are good, but about a mid throttle stab from stand still or while cruising results in the lean pop from the intake. Taking off from a stop or accelerating shows initial lean 17-18:1 on the wideband then comes in around 14-15:1 while .cruising. So every time I give it throttle it is registering an initial lean condition at any speed/RPM.

In simple words is there 1 parameter to change to give that big "pump shot"? And which way do I make the adjustments to that parameter, increase or decrease?

From what I read, I *think* it is Acceleration Enrichment Factor vs Change in LV8. But what way do I go, increase or decrease the numbers and at what points?

Orr89RocZ

iTrader: (20)

That should be it, atleast a good starting point. The larger delta lv8 values are more for large quicker throttle transitions. I would try increasing those numbers a good bit to see if the issue goes away

ULTM8Z

Excessive spark timing can also result in some off idle lean-pop.

But other than that, I agree with Orr89RocZ.

Your manifold probably has some decent sensitivity to AE like my Miniram (generally short runner, log style plenum, etc).

Also on mine, I try to keep the vacuum line between the fuel pressure regulator and the manifold as short as possible and the only thing that's shared with it on that vacuum line is the vacuum gauge in the interior. You want the regulator to be as quick/responsive to the changes in manifold pressure as possible. Especially when you're into quick throttle transitions. Otherwise you could be attempting to mask a delayed regulator response with an unncessary increase in AE pulse width.

Unfortunately, $6E doesn't have near the fidelity on AE tuning as $8D. Hopefully the AE vs LV8 does it for you. If it does it mostly at hot temps, you can also play with the LV8 AE Coolant Factor vs Coolant Temp, richening up the hotter coolant temps as well.

Orr89RocZ

iTrader: (20)

Also the power enrichment vs rpm can be used somewhat to help especially in lower rpms. It did on my 383, although thats more a steady state deal once in power enrichment mode. Check to see if its engaged when this happens. Could try increase the min lv8 to engage power enrichment to see what happens at initial mild pedal change from the stop. But sounds like it could be ae issue.

ULTM8Z

Oh, if there's something like that in $6E, my guess is that'll help a lot. I quickly scanned through it Tunerpro for my earlier reply as I'm not that familiar with $6E.

On mine, I have minimum delta-MAP to engage AE delta MAP as well as minimum delta-TPS to enage AE TPS. The vacuum change per throttle movement is very large on the Miniram, so it's very sensitive to throttle transitions like I said. Making these parameters more sensitive really helped at all rpms and load conditions. Amazing that the speed of these events occurs on the order of a couple of milliseconds, yet it's very noticeable by seat of the pants.

89fast5oh

I upped the Acceleration Enrichment factor vs change in lv8 by 30 in all fields. It seemed to kinda help. I had to really try to make it pop, which I could make it do during different driving conditions. It seemed to do it mostly when in 2nd or 3rd gear going about 30-35 mph and stabbing the throttle to about 1/4-1/3. Pops and stumbles for a split second then takes off. Once its going the WB is showing good rich AF ratio.

I wish the $6E was as easy as AUJP $8D. I used that on my 1985 converted to 1991 speed density. It had clear AE parameters.

IROCThe5.7L

I had the same exact issues when I was tuning my 427 with a HSR. I saved this post from here. Not sure who wrote this. But I followed this and it solved my issue. Then I slowly tweaked it after.

89fast5oh

I also tried all that first. The only thing I didn't change was the timing from idle to 3000, but mine is showing pretty close at 24 and 34.

It did nothing for me at all.

I am going to add more to the LV8 at 64 and 128 to see if that works. If not I will put all those changes in along with the change to Acceleration Enrichment factor vs change in lv8

Dominic Sorresso

In ur scans, are u seeing any knock retard when u stab the throttle?

89fast5oh

No I am not.

Dominic Sorresso

I was recently experiencing similar conditions when trying to tune for WOT on my LT5. Needed more timing. As i n +4-5*

89fast5oh

I tried those changes again along with massive increase in acceleration enrichment vs lv8 and it seems to have got ride of the lean pop. But I might have went too far and have now created a instant off idle dead spot. I scaled the ae vs lv8 back buy 10 points at lv8 - 64. Maybe tomorrow I'll get to check it out.

I also want to shout out to TunedPerformance for really helping me out with the majority of the tune.

ULTM8Z

Yeah, when it comes to AE, more is not always better.

Not sure how this translates to $6E, but hope some of it helps... and my suspicion is the ProFlo manifold behaves similarly to the Miniram.

One thing I'm finding with the Miniram is that it likes a very quick, fairly large shot of AE that tapers off very fast. In $8D, that seems to mean focusing more on the AE delta-TPS. Delta-MAP AE can very easily cause flat spots... so much so, that for as notorious as the Miniram is for wanting more and more AE, my current bin actually has the delta-MAP AE leaned out more than a 90-92 TPI.

But the delta-TPS AE is where its at. As it stands, it's astounding how razor sharp I've been able to get the throttle response on this thing...