ULTM8Z

I meant to post up on this a while ago, but forgot...

This may be more applicable in situations with modified engines as well...

In $8D, there's an AE parameter entitled AE Delta MAP Factor Multiplier vs TPS. (Not a delta TPS, but an absolute value of TPS)

When you start playing around with the AE Delta MAP (especially adding more delta MAP AE to correct for hesitations and off-idle stumbles), my experience has been that it can have a negative effect on this neutral to drive transition. When you go from neutral to drive, there's a delta MAP event associated with it, so the ECM will dump in some fuel. However, it's such a low load (at least with mine) that it was causing a momentary stumble due to an overly rich condition.

I found that table AE Delta MAP Multiplier vs TPS and scaled down the value for 0% TPS to 0.5 (the factory values are 1.00 for the entire table). That seemed to do the trick in firming up that transition. The stumble was eliminated.

Since the only time I ever really get a quick delta MAP event with throttle completely closed (0% TPS) is during idle conditions, it seems to be the perfect way to tailor the delta MAP for idle conditions without affecting the AE during driving conditions.

Any rate, figured this may be helpful to folks who may be struggling with stalling or rough transitions when going from neutral to in-gear.

ULTM8Z

Looks like my logic behind this may be incorrect...

In converting over to SAUJP as my baseline start point, I'm running a compare in TunerPro between my last ANHT-based bin and the new SAUJP-based bin to ensure everything is the same. The ANHT-based bin was built in TunerCat.

However, when I came across AE Delta MAP Factor Multiplier vs TPS (the table I discuss in my original post above), I noticed the value in TunerPro is the inverse of what I entered into TunerCat.

I entered .5 into the 0% TPS in TunerCat, but TunerPro is showing a value of 2 (which is basically 1/0.5).

So in reality, I'm actually adding fuel, not subtracting it? According to TunerPro, this table provides more AE with increasing values.

This seems very counter-intuitive...

When I increase the AE vs delta MAP for better throttle response, my neutral to drive transition gets worse. I had originally thought this was a side effect due to throwing in more fuel due to the delta MAP event when I shift from neutral to drive. So I figured decreasing the value in the AE Delta MAP Factor Multiplier vs TPS would compensate for it.

But now it turns out I'm actually m throwing even MORE fuel at it with this AE Delta MAP Factor Multiplier vs TPS and yet the neutral to drive transition improves?

What am I missing here? Is TunerCat backwards? Or is TunerPro backwards?

RBob

iTrader: (1)

Looking at the code the larger the value in this table the more AE there is:

The value from that table is used as a multiplier of the value from this table:

So a larger value will cause more AE.

RBob.

ULTM8Z

So then my original thinking was backwards. Some how the engine was going lean and then i was adding fuel which is what helped...

RBob

iTrader: (1)

The problem is the conversion equations. In a case like this need to look at the raw values for a sense of a sanity check.

RBob.

rt66er

iTrader: (2)

Okay, I know this thread is a couple of years old, but I'm confused by what TunerPro is displaying.

With an AXXB-based BIN and $8D.xdf, I changed the "Enrich Accel Delta MAP Factor Mult. Vs. TPS" at 0 TPS to 0.67.

When I open the same BIN in 8D.xdf, the factor now shows 1.49 at 0 TPS.

FWIW, 8D.xdf note reads: "The amount of AE that is calculated for a state change in TPS. If the TPS change X amount the multiplier will factor in and provide more AE shot if its value is increased. Recoding the value decreases TPS delta AE being added." and the conversion is: "64.000000 / X + 0.000000"

$8D.xdf conversion is: "(0.015625 * X) + 0.000000"

Question is: which is increasing AE and which is decreasing AE? (I'm trying to improve P to D idle transition.)

Sorry, but I'm old and easily confused.

Orr89RocZ

iTrader: (20)

how much of that is just load from converter and gear engagement? You should see rpm drop and load increase which i think could also be tuned with the rpm difference from park neutral values combined with idle spark table at the various loads and maybe rpm error idle spark advance? Think that may help handle the load transition

its basically idling so i cant see fueling have huge impacts there but could be wrong

ULTM8Z

One thing you can also do to see if the AE delta map is an issue here is to increase the map threshold to say 20kpa for 0%TPS.

this is in the table for AE delta map threshold vs TPS.

If you see no improvement, then it's not s delta map AE issue during transition from park to drive.

rt66er

iTrader: (2)

Thanks, but I'm not sure what you're telling me. If I move the threshold to 20 kPa, does that mean that there will be no AE until there is a 20 kPa change? Looking at my last log, P to D shows a momentary jump from 30 kPa (700 rpm in P) to 50 kPa (475 rpm in D). It then goes back and forth a bit and settles at about 40 kPa @ 600 rpm.

ULTM8Z

Yeah pretty much. When you go from Park to Drive, there's a momentary change in engine load (and manifold pressure as a result). If that change is large enough to cross the delta-MAP threshold to engage the delta-MAP AE, you'll get a shot of fuel during the transition... and if that shot of fuel is large enough, it could cause a stumble like you're seeing.

I think the 8D calibration has the factory delta-MAP threshold at something like 3 kPa at 0% TPS (closed throttle) before the delta-MAP AE engages.

So what I'm suggesting is (for diagnostic purposes) set that value to something really high in order to "disable" it during the Park to Drive transition... 50 or 100 kPa even. If the stumble goes away, then you know it's AE fueling related (i.e. getting too much fuel).

rt66er

iTrader: (2)

Cool, thanks, I'll give it a shot (pun intended).

Dominic Sorresso

Looking at my $D0A mask, I don't see a table for Delta MAP v TPS%, but I have attached .jpg showing certain AE related constants

rt66er

iTrader: (2)

Well, that definitely had an effect. Even in open loop, idling at 950 rpm (cold) when I put it in D, it struggles and dies almost immediately. Tried it twice, same result. Should I assume from this test that the AE shot is inadequate? I had bumped it from 1.0 (stock AXXB) to 1.5. I guess I'll try bumping up to 2.0 (and resetting the threshold back to 3 kPa). BTW, I'm running 20.4 SA at all idle cells.

ULTM8Z

I'm not sure I understand what you did...

You're saying you lowered the threshold from 3 to 1? That's the opposite of what I was saying to do. That would mean you're making the AE map more sensitive than it was before.

I'm saying change the threshold to something really high, like 50 kPa to ensure you don't get AE delta-MAP coming in during the transition.

rt66er

iTrader: (2)

Sorry, no I raised the "Accel Enrich Delta MAP Enable Threshold Vs TPS" to 25 kPa (from 3.3) at 0 TPS, and it died immediately when I put it in gear. I'm putting that back to 3.3 and increasing the "Accel Enrich Delta MAP Factor Multiplier Vs. TPS" from stock 1.0 to 2.0 at 0 TPS.

rt66er

iTrader: (2)

Well, that didn't seem to help, so I went to 3.0, which made it even worse on P to D transition. Any other suggestions? Before the TPI conversion there was no problem with the P to D transition, so there must be something in the tuning that is creating this situation.

ULTM8Z

Maybe keep an eye on the O2 voltage... granted it's not a WB, but my guess is of the car is dying some thing a little extreme is happening... either the O2 will peg rich at nearly 1V or peg lean at <100mV.

If you can determine a rich or lean condition then you can react accordingly

rt66er

iTrader: (2)

Thanks, yeah, it looks like it's going lean. The typical O2 swing appears to get interrupted by the transition. When it bottoms out at 450 rpm, the O2 is showing 234.6 and it continues to fall until the rpm picks back up. Timing peaks at 30 degrees at the same time and injector pulse width is also showing an increase (though it's hard to read with this scale). Injector pulse width actually rises from 1.69 (prior to transition) to a peak of 3.14 (where the rpm begins to bounce back). This is why I always assumed that it was going lean and needed more fuel (pump shot) but when I increased the Accel Enrich Delta MAP Factor MultiplierVs. TPS, it got worse.