engine runs good, idle still wacky (sucks) - 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 04-18-2014, 01:24 PM   #1
Elite Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2013
Location: Staunton, Va
Posts: 2,399
Total Cats: 200
Default engine runs good, idle still wacky (sucks)

I was stoked to find hornetballs idle write up last night and was certain I had found my answer! followed the write up word for word and the end result was exactly what I have always had. An idle in the 40-50 kpa range. Just a small bit of throttle (1800rpm) and it comes down to 25-30 kpa. "It must be a vacuum leak" I said. proceed to spray the engine compartment with carb cleaner. nothing. spray it in the intake pipe and idle raises. clog the intake pipe with a t shirt and then search with carb cleaner for a leak again.Nothing.
No amount of timing in the low rpm range brings down the kpa. start @10* then work my way up to 30*(30 just to see, I know i should be 10-15)
All idle area cells are constant in timing and ve1 up to 1500rpm,idle still fluctuates 75-100 rpm and afr bounces back and forth 1 whole number.
With hornetballs settings, I have to turn the idle screw out 4 turns to get the idle in the 1000rpm range.

Help me please.

DIYPNP
tunnerstudio
Intake,exhintake, header
Engine timing [email protected]* then -10 use table in TS
AFR - do not incorperate, being used during all of this
Runs like a champ on the stock ECU
ryansmoneypit is offline   Reply With Quote
Old 04-18-2014, 04:55 PM   #2
Elite Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2013
Location: Staunton, Va
Posts: 2,399
Total Cats: 200
Default

CurrentTune.msq

some of the maps may be nerdy now. At my wits end with the idle issue I started making frantic changes to see if I could get different results.

Anyone near central Va. willing to tune this thing?
ryansmoneypit is offline   Reply With Quote
Old 04-19-2014, 12:15 AM   #3
Elite Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2013
Location: Staunton, Va
Posts: 2,399
Total Cats: 200
Default

seriously?
ryansmoneypit is offline   Reply With Quote
Old 04-19-2014, 09:52 AM   #4
Senior Member
 
Join Date: Apr 2011
Location: Hollywood, FL
Posts: 523
Total Cats: 18
Default

Seriously? Two things:

"All idle area cells are constant in timing and ve1 up to 1500rpm,idle still fluctuates 75-100 rpm and afr bounces back and forth 1 whole number."

VE values shouldn't be all the same through 1500 because the engines VE is not the same which will cause your AFR's to fluctuate and so will your idle.

As far as your bad vacuum readings at idle, its a mechanical problem and no amount of ECU tuning is going to help.
hector is offline   Reply With Quote
Old 04-19-2014, 10:17 AM   #5
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,653
Total Cats: 1,559
Default

If your engine has ring wear it will not make as much vacuum at idle as one with low mileage and good ring seal.
sixshooter is offline   Reply With Quote
Old 04-19-2014, 11:13 AM   #6
Elite Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2013
Location: Staunton, Va
Posts: 2,399
Total Cats: 200
Default

OK This makes sense.Before I started messing with the me yesterday, it was pretty solid. I just had the higher than normal kpA, reading. I also think I misunderstood the ve part of the instructions.
This engine has 180,000mi. Perhaps this 40-45kpa is just what I'm going to get at idle?
ryansmoneypit is offline   Reply With Quote
Old 04-19-2014, 12:14 PM   #7
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,653
Total Cats: 1,559
Default

It could be, but you are right. That's a bit too high.

Sometimes vacuum operated components leak internally. Block each one of the little lines individually and see if they effect idle speed. You can do this quickly and easily by squeezing each one closed with some vice grips. It doesn't even involve removing them.
sixshooter is offline   Reply With Quote
Old 04-19-2014, 12:36 PM   #8
Elite Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2013
Location: Staunton, Va
Posts: 2,399
Total Cats: 200
Default

Sounds good. I'll try it when I get home today. Thanks
ryansmoneypit is offline   Reply With Quote
Old 04-19-2014, 05:30 PM   #9
Elite Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2013
Location: Staunton, Va
Posts: 2,399
Total Cats: 200
Default

Pinched every vacuum line in various locations. No change.
ryansmoneypit is offline   Reply With Quote
Old 04-19-2014, 08:49 PM   #10
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,653
Total Cats: 1,559
Default

Maybe that's just where it is going to be.
sixshooter is offline   Reply With Quote
Old 04-19-2014, 09:40 PM   #11
Elite Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2013
Location: Staunton, Va
Posts: 2,399
Total Cats: 200
Default

I have accepted that. It Idles well, just at an odd number.
ryansmoneypit is offline   Reply With Quote
Old 04-23-2014, 02:15 PM   #12
Elite Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2013
Location: Staunton, Va
Posts: 2,399
Total Cats: 200
Default

Still messing with this idle issue. When I test the valve in attempt to tune closed loop, I can eventually kill the engine with a low enough #. coming down from 35, somewhere around 15 the idle falls so low that the engine will die. Any thoughts on that? it was my understanding that it should just stop affecting the idle, not stop the engine all together.
ryansmoneypit is offline   Reply With Quote
Old 04-23-2014, 03:05 PM   #13
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,833
Total Cats: 1,786
Default

a few random thoughts from skimming this thread:

vacuum will increase if you increase the idle speed.

a leak pre-TB will not affect the MS...you can take the entire intake off and run an open TB.

you do not have a leak if you can stall the car by reducing the idle valve fully.

as far as the idle valve, I tune mine so at the lowest possible duty cycle, the idle drops to about 650-700RPM at the lowest. I do this so on cold days you can still maintain a typical 850-900RPM idle speed (since you less air when cold).

typically the idle valve duty for a 90-97 is working between 30-60%DC.

does hornetball even have "settings" for ms2? I thought his write up was for MS1?
Braineack is offline   Reply With Quote
Old 04-23-2014, 05:04 PM   #14
Elite Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2013
Location: Staunton, Va
Posts: 2,399
Total Cats: 200
Default

OK. I was getting about 28-67 with 650-1200 rpm. Still with a strange 40-45 kpi though.
Thanks
ryansmoneypit is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
94-97 JR Header, FM Stage 1 Happy Meal, Carillo rods & Supertech Pistons eddy1128 Miata parts for sale/trade 8 12-10-2015 06:34 PM
Headphones PaperMate Insert BS here 32 09-25-2015 09:22 AM
VE values too low? compuw22c MEGAsquirt 4 09-12-2015 08:42 PM
ME221 Now has Autotune and Long Term Fuel Trim Tables Motorsport-Electronics ECUs and Tuning 0 09-05-2015 09:02 AM
Help Rough Idle Backwoodsballer General Miata Chat 0 09-04-2015 07:39 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 PM.