Accel Enrichment Issues

http://www.diyautotune.com
Post Reply
dj_smooth
240sx Wannabe
Posts: 196
Joined: Sun Aug 10, 2008 12:35 pm
Location: Guam-- Moore, Oklahoma

Accel Enrichment Issues

Post by dj_smooth » Wed Oct 21, 2015 5:51 pm

Megasquirt 2 PNP
KA24DE
TD06 20G
9:1 Compression
91 Octane
Stock Head
550cc Injectors

I understand the 4 points on the TPS side represent the rate of change.
-VE table has to be pretty well put together before messing with accel enrichments...

I've read over the manual many times and have watched the video with Scott Clark adjusting the accel enrich at a megameet seminar. I however still cant seem to figure it out. Driveability is horrible.

He said note what idle pulse width where and then double that. I believe that should be my highest pulse width at my fastest rate of opening. Not quite sure.

Accel TPS dot: should be set so that little to no enrichment occurs during light throttle travel?
Decel Fuel Amount: is how much fuel is cut out ???????


Full Accel below RPM: Does that mean that below that RPM, AE trigger will automatically go to my fastest throttle opening ( last point on the graph) and use that pulse width?

Accel time is how long enrichment last and then accel taper is how fast after that it goes to the end pulse width?


I know pretty much everything that i'm repeating is covered with the helpful hints on tunerstudio and the megamanual. I however can not seem to get this figured out.

Also, if I make adjustments, do I need to re-burn the ecu before they take affect, or do they change in realtime just like all the other tables?
Attachments
accel enrichement tuning.msl
Accel Enrich Logging
(1.96 MiB) Downloaded 94 times
DELETE 2.msq
Tune File
(109.08 KiB) Downloaded 117 times

User avatar
Matt Cramer
KA-T.org Sponsor
KA-T.org Sponsor
Posts: 934
Joined: Mon Sep 15, 2008 5:34 am
Contact:

Re: Accel Enrichment Issues

Post by Matt Cramer » Thu Oct 22, 2015 7:05 am

Accel TPS dot: should be set so that little to no enrichment occurs during light throttle travel?
Yes, you want it to trigger when you stab the throttle, not when you do a slow roll on.
Decel Fuel Amount: is how much fuel is cut out ???????
It is a multiplier, so 100% = no cut. I typically recommend setting it to 100% on anything with a manual transmission. If you're concerned about pulling fuel on a sudden lift, use the Enhanced Acceleration Enrichment to handle that; it does a better job.
Full Accel below RPM: Does that mean that below that RPM, AE trigger will automatically go to my fastest throttle opening ( last point on the graph) and use that pulse width?
No. Below this RPM, it uses the graph. Once you get above this RPM, it starts backing off the acceleration enrichment, and turns it off completely at "Zero Accel Above". The reason is that the faster airflow means less fuel puddling and therefor less need for AE at high RPM.
Accel time is how long enrichment last and then accel taper is how fast after that it goes to the end pulse width?
Yes.
Also, if I make adjustments, do I need to re-burn the ecu before they take affect, or do they change in realtime just like all the other tables?
IIRC, it's just like the other tables. They change in real time but you need to burn the changes before closing that screen.

One other thing I saw is that your curve is flatter than a well tuned curve typically looks. Usually you have less AE at low TPSdots. Also, you usually don't need to bother tuning for TPSdot above 400. After you get past snapping the throttle open in 1/4 second, there's not much change with snapping it open in 1/8 second.
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
Nissan plug and play engine management now in stock!

dj_smooth
240sx Wannabe
Posts: 196
Joined: Sun Aug 10, 2008 12:35 pm
Location: Guam-- Moore, Oklahoma

Re: Accel Enrichment Issues

Post by dj_smooth » Mon Nov 02, 2015 7:55 pm

Matt, would you mind labeling the graph that logs AFR,TPSdot, and MAPdot? I think it would be easier for me and other users as well to see what part of the bottom portion of the screen adjust what portion of the real time graph logger. For instance, where the afr dips to the bottom of the graph (2 spots) and then the time it takes to peak then back down to level out would be better easier understood with circles around those portions pointing towards the corresponding part adjustment parameter.

Image

User avatar
BigLoukaT
Dont Question My Nissan Knowledge
Posts: 879
Joined: Sun Jul 23, 2006 11:03 am
Location: MA

Re: Accel Enrichment Issues

Post by BigLoukaT » Tue Nov 03, 2015 11:06 am

That is a lot of accel taper time. Usually that's on the order of tenths of a second (.1 or .2 in the base msq)
Cold accel adder seems high as well
1990 S13
Boosted single slammer
MS DIYPNP
npx from 240sxforums wrote:i figure from my very limited knowledge about the 240 and under the hood about cars in general i would follow the sr20det trend.

dj_smooth
240sx Wannabe
Posts: 196
Joined: Sun Aug 10, 2008 12:35 pm
Location: Guam-- Moore, Oklahoma

Re: Accel Enrichment Issues

Post by dj_smooth » Wed Nov 04, 2015 1:00 pm

Thanks for pointing that out. I meant to set it to .3.

That was a huge part of my problem. I've also noticed that making changes to the AE table had to be burned before Megasquirt would respond to any of my new inputs. I was chasing my tail for a long time trying understand why none of my inputs made a difference. Once I burned it after my inputed values, the changes became apparent.

User avatar
BigLoukaT
Dont Question My Nissan Knowledge
Posts: 879
Joined: Sun Jul 23, 2006 11:03 am
Location: MA

Re: Accel Enrichment Issues

Post by BigLoukaT » Sun Nov 08, 2015 6:39 pm

I've been caught by that too. I went back to the manual for a refresher: section 1.5.1 http://www.msextra.com/doc/pdf/html/Meg ... e-3.4.html
Basically, anything besides fuel or ignition tables require a burn to take hold.
Thinking back, I have changed ae settings without burning and was not seeing changes.
Post up a new log when you get a chance, I'm curious to see what you came up with and how the engine sensors are responding.
1990 S13
Boosted single slammer
MS DIYPNP
npx from 240sxforums wrote:i figure from my very limited knowledge about the 240 and under the hood about cars in general i would follow the sr20det trend.

Post Reply