AEM
Sponsored by:
Sponsored by:

Need help with low rpm stumble on FIC

 
Old 02-05-2011, 04:38 PM
  #1  
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Nov 2010
Location: Winston Salem, NC
Posts: 45
Total Cats: 0
Default Need help with low rpm stumble on FIC

Could use some advice please because this stumble is making me nuts.
I have an rhb5 BEGI/cartech s3 system in my 91 1.6. The kit came with a vortech RRFPR which I installed with a 225 walbro.This turned out to be inadequate at around 6psi once I got the car on the dyno with a tailpipe sniffer. To avoid the lean condition I added an AEM FIC and was able to get as rich as I wanted throughout the rpm range by controlling the pulse width. Everything is tuned pretty conservatively and peaks out around 166hp.
I am very happy with the setup and have ben able street to tune everything but one really annoying quirk out of it.
When I'm at low rpm with moderate load at two spots (about 2800 and 3600) and I put my foot down to go into boost, the car stumbles and bucks like crazy. It almost feels like bad ignition wires which caused me to change them out. There is also nothing crazy going on in the ignition map in case you are wondering. Whats really weird is that it happens at various RPM and load cells each time.
I have tried richening and leaning to no avail and I can't make it go away. It is getting increasingly hard to drive around it.
Has anyone got any experience with this problem or any suggestions?
Hemiarch is offline  
Old 02-05-2011, 06:30 PM
  #2  
Elite Member
 
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,318
Total Cats: 12
Default

What I would do is setup the f/ic to replace the your mass air flow.
http://forum.aempower.com/forum/index.php?topic=23732.0
That way the f/ic is using the map sensor built into it for controlling all parts of fuel delivery.

That's my suggestion anyways.
dustinb is offline  
Old 02-05-2011, 07:39 PM
  #3  
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Nov 2010
Location: Winston Salem, NC
Posts: 45
Total Cats: 0
Default

Is that what you think is causing the stutter? The stutter happens out of boost with only the AFM providing info to the stock ecu. When boost kicks in and the FIC is "adding" fuel, everything runs smoothly.
Oh, one more thing, I'm using 1.8 injectors in the 1.6 motor.
Hemiarch is offline  
Old 02-05-2011, 11:13 PM
  #4  
Senior Member
iTrader: (2)
 
Join Date: Jun 2007
Location: Shalimar, FL
Posts: 957
Total Cats: 7
Default

Are you substituting a signal for o2 to the stock ecu? That way it's not fighting your FIC as far as fueling goes. Search for olderguy o2 clamp. If you don't have a wbo2 sensor you really should get one. Find out what your AFRs are doing when the bucking happens.
messiahx is offline  
Old 02-16-2011, 11:40 AM
  #5  
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Nov 2010
Location: Winston Salem, NC
Posts: 45
Total Cats: 0
Default

Turns out the problem was the FMU. Once it was off and retuned with a set of rx8 injectors., the car started running completely smoothly.
Hemiarch is offline  
Old 02-17-2011, 06:24 PM
  #6  
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Nov 2010
Location: Winston Salem, NC
Posts: 45
Total Cats: 0
Default

I think I'm running a little rich. I'm backfiring a little under vacuum and the car reeks of gas. My idle is also a little rough now.
At this point I have the exhaust bunged for a wideband, but no permanent one in place to tune with.
What is the cheapest way to do this? Do those of you who run an FIC leave a permanent one in place and datalog?
I dont really care for a permanent gauge in the car, but will do this if it's cheaper than getting one to plug into the FIC.
Hemiarch is offline  
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
JesseTheNoob
DIY Turbo Discussion
15
09-30-2015 02:44 PM
viriiguy
General Miata Chat
5
09-28-2015 07:39 PM
JStoops
Miata parts for sale/trade
0
09-28-2015 05:35 PM
DonPlatt
WTB
0
09-25-2015 02:57 AM


Thread Tools
Search this Thread
Quick Reply: Need help with low rpm stumble on FIC


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.