Can someone explain to me what the "Accel Enrichment" in EvoScan is? I can't figure it out.

 

Drive: my wife pitter putting around today.
Graph: XY Scatter
"Accel Enrichment" vs Load calculated via MalibuJack's little app

...just trying to figure out what the Accel Enrichment is....

 

Drive: my wife pitter putting around today.
Graph: XY Scatter
"Accel Enrichment" vs TPS

 

The best I've been able to tell, is its a supplimental enrichment based on TPS voltage, but I have no idea what the value itself means other than logged, its a value from 0-100.. Only the value is limited from 0-2 and its unclear if that is a TPS voltage value, I haven't attempted to match the value to anything relevent yet.

What I'm thinking is the closer to the voltage you hit, the closer to 100% the logger shows.. It does not decay like an accelerator pump value..

Anyone have the stones to raise the value and log TPS voltage and see if it hits 100% at that value?

 

Looking at your charts, it seems to vary a bit depending on TPS, and 50% tps is likely 2v or so.. if it was actual TPS voltage in the ECU's Map, it would hit 100% just before you jump out of open loop.. so I guess thats not correct..

The ECUFlash program calls the scaling EnrichmentAdj so its definitely not what I had assumed earlier.. Perhaps its a modifier for injector duty?

 

I have my accel values set @ 1.99 from 2500-7500.

this was one of the first things I 'tweaked' with ECUFlash when I first got it. I was under the impression that it was a multiplier for how fast your ECU started to add fuel based on TPS position.

I kind of forgot about the settings until about a month ago when I noticed it while just looking at my flash. I switched the values back to stock and my A/F got totally messed up. The car was crazy lean in some areas and if I remember correctly it did take longer to 'richen up' once I stepped on the gas.

 

As far as I have been able to tell, Accel Enrichment is what is used by the ECU to determine how much extra fuel to add in response to large/sudden positive changes in TPS values ... ostensibly to avoid a tip-in lean condition.

I've actually reduced my accel enrichment values slightly to get less fuel dumped into my engine when I stomp on the gas.

l8r)

 

Funny, I just typed up a post for this exact same subject, then found this thread before sending it!

If it was just responding to jumping on the gas, wouldn't it taper off if you hold the throttle at the 'jumped' position? I mean, if you jump to 50% then hold it, shouldn't the AE number jump up, then taper back down to 0? This is definitely not what I see in my logs. Instead, it holds the value until you lift off the gas.

In EcuFlash, there is a 1-D table with 15 values. Here's a stock EVO 8:

RPM %
500 1.625
1000 1.5
1500 1.125
2000 1
2500 1
3000 1.20312
3500 1.32812
4000 1.42969
4500 1.42969
5000 1.42969
5500 1.42969
6000 1.42969
6500 1.42969
7000 1.42969
7500 1.42969

What does the % value really represent? What would be a good strategy for calibrating this function? Maybe: Go to each rpm, floor it, look for knock. If no knock, then drop the value, rinse and repeat??

Back to my honest, actual motive: all the values in my mail-in flash are bumped up to 1.98438 across the board. I'm wondering if this is dumping fuel unnecessarily (and pissing away my fuel economy). I'd like to return it to stock (for a starting point) and start tweaking, but I'm not touching anything until I fully understand how it works.

Rob W.

 

Just a post I found on the subject:

http://forums.turbobricks.com/showthread.php?t=46690

 

I'm with you on this 100%. I think the table in EcuFlash and the value that EvoScan report are possible not related. They are named the same, but since no one really knows what they do, how do we know that they were named correctly? I'd say the ROM disassembly that's going on will give some insight into what these really mean/do.

I think that one if not both of them have to do with the rich condition some folks are seeing during 1st-2nd-3rd-4th gear accelleration. I sometimes see it when not going through the gears. 1/2 to a full point richer AFR in these cases.

 

I'm inclined to agree with you.. My understanding of how this type of function should work is that its supposed to compensate for sudden changes in throttle input and not as a throttle based perminent enrichment..

Time will tell, The only way to really know is to alter the value and see if it responds in that requestID in a predictable manner.

However I chose not to touch the value in that table until I'm 100% certain of what its functionality is.

FWIW there are a dozen or so more tables and items in the stock ROM that appear to have configuration parameters that have not been traced to a function yet..

 

Same here, though I never lowered the values.

 

any news on this front?

I notice a spike down on full throttle application, but AFR (accel enrichment) backs off too quickly and I go lean before the AFR map collects itself. The boost/load rises too fast for the map to maintain afr. I'd like to try prolonging the enrichment for another half second.
Its not an issue of the afr map being to lean.

I have an electronic boost controller so I have not touched the boost maps.

 

Interesting to note that mine was set to 1.98 accross the board over a year ago in a flash (or either custom tune) from a vender.

I have changed the values respectively to where I would want "enrichment" and have seen some smoothing of A:F. But on the other hand that could just be a placebo effect

 

I did try upping the inputs but mine only goes to 1.99.

as yours, mine had been set to 1.98 in a flash from the past.

if this were a typical standalone emc you would have "accel enrichment" and "throttle pump sensitivity" maps to fret over.