Help me figure my idle and AFR problem. - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


General Miata Chat A place to talk about anything Miata

Reply
 
 
 
LinkBack Thread Tools
Old 03-14-2008, 10:59 AM   #1
Elite Member
Thread Starter
iTrader: (30)
 
Join Date: Aug 2007
Location: Va Beach
Posts: 7,282
Total Cats: 0
Default Help me figure my idle and AFR problem.

1. My Idle rpm and my idle AFP's are all over the place and my gas mileage sucks bad. Sometimes I idle rich, other times lean. Sometimes my idle is below 500 rpm, other times above 500 and sometimes above 1000.

2. When crusing and very light on the gas I run lean 15-16.0, if I give a slight amount of gas the I go rich between 11-10.0. When WOT its usually low 13's. When I decel in gear my afr's go off the chart lean. The check engine light came on this morning when at a light but went off once I started moving. Yesterday I replaced the O2 sensorwith a new one and the IAC with one a friend gave me, which means I have no idea if its any good. After changing both parts my condition seems to have worsened.

Setup Is T2854,1.8inj,begi AFPR.

Here are a few videos of my idle and AFR's. Please help me figure this out. I really want to get this fixed before I get my MS from Scott.

Thanks for your time.





__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
levnubhin is offline   Reply With Quote
Old 03-14-2008, 11:06 AM   #2
Elite Member
iTrader: (39)
 
Zabac's Avatar
 
Join Date: Sep 2007
Location: High Point NC
Posts: 4,854
Total Cats: 8
Default

your settings are wrong...it is impossible to idle at 4-5 AFR's


edit-im not gonna delete what i said, but i am so wrong...i didnt watch the videos until after i posted...sorry

Last edited by Zabac; 03-14-2008 at 11:08 AM. Reason: im an idiot
Zabac is offline   Reply With Quote
Old 03-14-2008, 11:17 AM   #3
Elite Member
Thread Starter
iTrader: (30)
 
Join Date: Aug 2007
Location: Va Beach
Posts: 7,282
Total Cats: 0
Default

lol, have you had your coffee yet? Where the heck did you get 4-5 afr?
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
levnubhin is offline   Reply With Quote
Old 03-14-2008, 11:19 AM   #4
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

looks pretty normal to me.
Braineack is offline   Reply With Quote
Old 03-14-2008, 11:23 AM   #5
Junior Member
 
Join Date: Jan 2007
Location: EXTREME Southern Illinois
Posts: 281
Total Cats: 0
Default

If you're using a mass-air system, it almost sounds like an intake leak. I don't have sound here at work so I can't hear how it's running. It SHOULD go full lean when you decel in gear (overrun shutdown).
DammitBeavis is offline   Reply With Quote
Old 03-14-2008, 11:24 AM   #6
Elite Member
iTrader: (39)
 
Zabac's Avatar
 
Join Date: Sep 2007
Location: High Point NC
Posts: 4,854
Total Cats: 8
Default

Quote:
Originally Posted by levnubhin View Post
lol, have you had your coffee yet? Where the heck did you get 4-5 afr?
thats what the screenshot looks like to me, maybe im blind, but it says 5.8 and one says 5.9 and the third says .4 etc.
nevermind, lol
Zabac is offline   Reply With Quote
Old 03-14-2008, 11:25 AM   #7
Elite Member
Thread Starter
iTrader: (30)
 
Join Date: Aug 2007
Location: Va Beach
Posts: 7,282
Total Cats: 0
Default

Quote:
Originally Posted by Braineack View Post
looks pretty normal to me.
Is that because I dont have any real engine management at the moment?

My fuel mileage is realy bad and idle is all over the place.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
levnubhin is offline   Reply With Quote
Old 03-14-2008, 11:27 AM   #8
Elite Member
Thread Starter
iTrader: (30)
 
Join Date: Aug 2007
Location: Va Beach
Posts: 7,282
Total Cats: 0
Default

Quote:
Originally Posted by DammitBeavis View Post
If you're using a mass-air system, it almost sounds like an intake leak. I don't have sound here at work so I can't hear how it's running. It SHOULD go full lean when you decel in gear (overrun shutdown).

Yes I still have my mass. I bet there could be an intake leak its not the best setup. Anyone else think so?
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
levnubhin is offline   Reply With Quote
Old 03-14-2008, 11:27 AM   #9
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by whaaamx5 View Post
thats what the screenshot looks like to me, maybe im blind, but it says 5.8 and one says 5.9 and the third says .4 etc.
nevermind, lol
word life
hustler is offline   Reply With Quote
Old 03-14-2008, 11:27 AM   #10
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

if you can unplug the iac and the idle isnt effected then its bad...whats your vacuum at idle?
Braineack is offline   Reply With Quote
Old 03-14-2008, 11:28 AM   #11
Elite Member
Thread Starter
iTrader: (30)
 
Join Date: Aug 2007
Location: Va Beach
Posts: 7,282
Total Cats: 0
Default

Quote:
Originally Posted by whaaamx5 View Post
thats what the screenshot looks like to me, maybe im blind, but it says 5.8 and one says 5.9 and the third says .4 etc.
nevermind, lol

Thats because the camera catches the lights flickering on and off.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
levnubhin is offline   Reply With Quote
Old 03-14-2008, 11:31 AM   #12
Junior Member
 
Join Date: Jan 2007
Location: EXTREME Southern Illinois
Posts: 281
Total Cats: 0
Default

That is a wideband right?

16:1 idle doesn't sound normal to me. Does it idle rough? Any cause of missfire including
too much fuel will make the O2 sensor read lean.
DammitBeavis is offline   Reply With Quote
Old 03-14-2008, 11:34 AM   #13
Elite Member
Thread Starter
iTrader: (30)
 
Join Date: Aug 2007
Location: Va Beach
Posts: 7,282
Total Cats: 0
Default

Quote:
Originally Posted by Braineack View Post
if you can unplug the iac and the idle isnt effected then its bad...whats your vacuum at idle?
Well I jut wend and unpluged the iac at idle and the idle dropped significantly. Plugged it back in and the idle went back up. Vacuum at idle is 19-20.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
levnubhin is offline   Reply With Quote
Old 03-14-2008, 11:36 AM   #14
Elite Member
Thread Starter
iTrader: (30)
 
Join Date: Aug 2007
Location: Va Beach
Posts: 7,282
Total Cats: 0
Default

Quote:
Originally Posted by DammitBeavis View Post
That is a wideband right?

16:1 idle doesn't sound normal to me. Does it idle rough? Any cause of missfire including
too much fuel will make the O2 sensor read lean.

It only idles rough when the idle itself is very low, otherwise no. Car runs strong, no missfire or hickups of any sort.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
levnubhin is offline   Reply With Quote
Old 03-14-2008, 11:41 AM   #15
Junior Member
 
Join Date: Jan 2007
Location: EXTREME Southern Illinois
Posts: 281
Total Cats: 0
Default

Quote:
Originally Posted by levnubhin View Post
It only idles rough when the idle itself is very low, otherwise no. Car runs strong, no missfire or hickups of any sort.
I would expect an actual 16:1 idle to be rough. Did you mess with any of the crankcase vents that would cause the PCV system to suck in unmetered air? Pull the PCV and stick your finger over the end of it so that the intake can't get air through it. See if it changes the idle.
DammitBeavis is offline   Reply With Quote
Old 03-14-2008, 11:51 AM   #16
Elite Member
Thread Starter
iTrader: (30)
 
Join Date: Aug 2007
Location: Va Beach
Posts: 7,282
Total Cats: 0
Default

Quote:
Originally Posted by DammitBeavis View Post
I would expect an actual 16:1 idle to be rough. Did you mess with any of the crankcase vents that would cause the PCV system to suck in unmetered air? Pull the PCV and stick your finger over the end of it so that the intake can't get air through it. See if it changes the idle.
No change.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
levnubhin is offline   Reply With Quote
Old 03-14-2008, 12:04 PM   #17
Junior Member
 
Join Date: Jan 2007
Location: EXTREME Southern Illinois
Posts: 281
Total Cats: 0
Default

Where is the Wideband sensor located in the exhaust?
DammitBeavis is offline   Reply With Quote
Old 03-14-2008, 12:16 PM   #18
Elite Member
Thread Starter
iTrader: (30)
 
Join Date: Aug 2007
Location: Va Beach
Posts: 7,282
Total Cats: 0
Default

after the cat delete "test pipe". Yes it is on the top of the pipe.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
levnubhin is offline   Reply With Quote
Old 03-14-2008, 12:25 PM   #19
Elite Member
iTrader: (9)
 
Saml01's Avatar
 
Join Date: Jul 2007
Location: NYC
Posts: 5,730
Total Cats: 2
Default

Could the base idle pressure on the AFPR be set wrong?

Can a car even idle at 5:1 afr?

Whats having me scratch my head is that you say it varies, from rich to lean at idle.

Any pattern? Is it correlated to something? Engine temp perhaps?
Saml01 is offline   Reply With Quote
Old 03-14-2008, 12:31 PM   #20
Junior Member
 
Join Date: Jan 2007
Location: EXTREME Southern Illinois
Posts: 281
Total Cats: 0
Default

I'm having a hard time getting past the smooth idle with a 16:1 mix. Can anybody else here idle smooth at 16:1? I normally have to go a touch richer than 14.7 to get a nice idle.
DammitBeavis is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM
Any pnp megasquirt for 2001 Big_gumby WTB 0 09-30-2015 04:34 PM
Low oil pressure after 1.8 swap and new turbo setup JesseTheNoob DIY Turbo Discussion 15 09-30-2015 03:44 PM
why is my car running like pewp? (tune/datalog) itsMikey MSPNP 3 09-28-2015 07:40 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 05:26 AM.