Very short lean spikes on throttle - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 06-27-2014, 11:21 AM   #1
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Jul 2012
Location: durham NC
Posts: 767
Total Cats: 115
Default Very short lean spikes on throttle

I am getting lean spikes when I get on throttle. I tried tuning them out with AE and now it spikes lean for a single data point, then goes rich for a third of a second, which makes me think I added too much AE/ AE isn't going to fix it. Is this something to worry about? TPSdot is at 35 right now.

I am running the canbus interface on an LC-2, is it possible that the sensor is polling faster than the combined latency of the mega squirt and injectors opening/delivering fuel?

Here is what my log looks like- it goes rich after the spike from all the AE I was adding to try and fix it:
Log Animation

Are there other possible causes? A timing issue? No misfire or stumble is felt and I am inclined to back the AE down again and not worry about it.
asmasm is offline   Reply With Quote
Old 07-03-2014, 09:01 AM   #2
Junior Member
 
Join Date: May 2011
Location: UK
Posts: 47
Total Cats: 0
Default

is the rich not just because you're back straight off the throttle again so all the fuel on the walls of the intake is pulled into the cylinder?

try logging it when you open the throttle and hold it fixed before you back out, and see if you still get the rich lump. my guess is that you need a little more AE.
skinny is offline   Reply With Quote
Old 07-03-2014, 10:36 AM   #3
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,904
Total Cats: 1,793
Default

too much AE added.

the only way to remove is lowering the threshold, possibly adding in MAP blending.

what version MS?

remember, AE is reactionary. the MS has to read your throttle, wait for it to breach the threshold, then apply any corrections.
Braineack is online now   Reply With Quote
Old 07-03-2014, 10:39 AM   #4
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Jul 2012
Location: durham NC
Posts: 767
Total Cats: 115
Default

It is an MS3 basic from reverent. I dropped the TPSdot to 35 and it didn't change anything. I re-tuned my AE so the car doesn't go rich. It drives really well so I am just ignoring the lean spikes.
asmasm is offline   Reply With Quote
Old 07-03-2014, 10:49 AM   #5
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,904
Total Cats: 1,793
Default

are you using AE or the accel-pump?

you should be using the accel-pump and the threshold can be hella low. like 10 or even below.
Braineack is online now   Reply With Quote
Old 07-03-2014, 11:05 AM   #6
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,206
Total Cats: 2,587
Default

if its for a split second I'd just ignore it too.
like scawt said - its reactionary. I spent a whole 2-3 days trying to eliminate mine, and would just end up with it doing it anyway but then pegging rich. as long as it feels buttery smooth, I don't think there's a problem
18psi is offline   Reply With Quote
Old 07-03-2014, 11:10 AM   #7
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,904
Total Cats: 1,793
Default

Quote:
Originally Posted by 18psi View Post
as long as it feels buttery smooth, I don't think there's a problem
agreed here.
Braineack is online now   Reply With Quote
Old 07-03-2014, 02:23 PM   #8
Supporting Vendor
iTrader: (10)
 
Reverant's Avatar
 
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,441
Total Cats: 199
Default

Remember that you need to have a fully tuned VE table. Otherwise it looks normal to me.
Reverant is online now   Reply With Quote
Old 07-04-2014, 03:30 AM   #9
Senior Member
 
Join Date: Mar 2006
Location: Schwarzenberg, Germany
Posts: 1,497
Total Cats: 81
Default

Quote:
Originally Posted by Braineack View Post
are you using AE or the accel-pump?

you should be using the accel-pump and the threshold can be hella low. like 10 or even below.
Hi Brain, just stumbled across this.
Would you mind sharing your settings for that Accel-pump style AE?
Zaphod is offline   Reply With Quote
Old 07-04-2014, 10:38 AM   #10
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,904
Total Cats: 1,793
Default



the first tpsdot/threshold values are a bit high cause I was having noise issues.

the algorithm behind the accel-pump is much improved over the AE wizard. The table is similar, but has negative values. As you can see, my table ignores throttle inputs from -240%/sec tpsdot to 25%/sec tpsdot.
Attached Thumbnails
Very short lean spikes on throttle-accel_pump.png  
Braineack is online now   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 12-15-2017 09:00 PM
Need help - Stock Balancer and Fastforward overlay pulleys Frank_and_Beans Supercharger Discussion 13 09-12-2016 09:17 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 11:11 AM.