AEM
Sponsored by:
Sponsored by:

AFR fluctuations at cruise

 
Old 03-18-2013, 12:18 AM
  #1  
Junior Member
Thread Starter
iTrader: (2)
 
Join Date: Mar 2008
Location: Navarre, Fl
Posts: 240
Total Cats: 4
Default AFR fluctuations at cruise

I'm having some fluctuation of my AFR when cruising around. Data log looks like a jagged sine wave. It will fluctuate from about 14.0 to around 16.2. My injector duty cycle remains constant. The idle fluctuation is only +-.4. At wot the afr is very steady.

The fluctuation during cruise seems a little excessive. Or is this normal?

Particulars about the car
2000
Begi cast manifold
Begi separated gas downpipe
Stock exhaust
SR20 turbo running 6psi
AEM FIC
AEM Uego afr guage
RX8 injectors
no intercooler

Thanks for any info.
ericsbestshot is offline  
Old 03-19-2013, 02:25 PM
  #2  
Elite Member
 
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,318
Total Cats: 12
Default

That's pretty normal.
dustinb is offline  
Old 03-19-2013, 02:30 PM
  #3  
Elite Member
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 10,360
Total Cats: 1,648
Default

Some fluctuation is normal, but that seems a bit excessive to me.


Or am i the only one that thinks that? The awful shitty "tuned" daily driver of mine fluctuates within 1 point, not over 2 like he's seeing.
concealer404 is online now  
Old 03-19-2013, 02:33 PM
  #4  
Elite Member
iTrader: (8)
 
Ryan_G's Avatar
 
Join Date: Jan 2012
Location: Tampa, Florida
Posts: 2,707
Total Cats: 200
Default

You May have a slight vacuum leak. I had this problem. I would have lean spike under constant light load. It is usually a very small leak from a hose that just is not very tight but not actually diconnected.
Ryan_G is online now  
Old 03-19-2013, 11:12 PM
  #5  
Junior Member
Thread Starter
iTrader: (2)
 
Join Date: Mar 2008
Location: Navarre, Fl
Posts: 240
Total Cats: 4
Default

thanks for the feed back guys. Is there anything else i should look at to get the AFR tighter?
Sensors? Coil pack?
ericsbestshot is offline  
Old 06-05-2013, 11:36 AM
  #6  
Junior Member
 
Join Date: May 2011
Posts: 51
Total Cats: 2
Default

Have you looked at your fuel trims with an OBD-II scan tool? Part throttle cruise is still in Closed loop. This is the hardest time for the FIC mostly on the tune side. You need to have the fuel table correct to achieve the correct AFRs and you need to have the O2 modification table correct to keep the trims in check so the ECU does not learn out the fueling changes you made in the table. If you have either fuel or O2 mod table wrong you will have very inconsistent ARFs. Vacuum leaks will make a big difference as well.

EB Turbo

EB Turbo
EB Turbo is offline  
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
satisfied
MEGAsquirt
144
11-05-2018 04:05 PM
russian
Miata parts for sale/trade
6
10-08-2015 03:01 PM
The Gleas
MEGAsquirt
3
10-01-2015 09:30 AM
Greasyman
General Miata Chat
2
09-28-2015 10:44 AM
itsMikey
MSPNP
3
09-28-2015 06:40 AM


Thread Tools
Search this Thread
Quick Reply: AFR fluctuations at cruise


Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.