AEM Wideband / Megasquirt Problem - 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 03-22-2010, 05:43 PM   #1
Junior Member
Thread Starter
 
Join Date: Jan 2010
Location: Atlanta GA
Posts: 167
Total Cats: 0
Default AEM Wideband / Megasquirt Problem

Hey Everyone!

I just installed my MegasquirtPNP, adjusted my idle, timing etc.

The only problem I have is that the Virtual Air/Fuel Gauge does not agree with my AEM Wideband.

At idle they will stay pretty close but when I drive the car the real gauge will say -- -- while the virtual gauge on Megatune will read a normal 12-15.

I've selected the proper gauge from the configurator, set Megatune to wideband and adjusted the voltage to 2.34. I then made sure that the power and ground went to the ecu's power and ground and disconnected the stock O2. I'm now officially out of ideas. Anyone have any suggestions?
D.dutton9512 is offline   Reply With Quote
Old 03-22-2010, 06:05 PM   #2
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,847
Total Cats: 1,788
Default

Braineack is offline   Reply With Quote
Old 03-22-2010, 06:33 PM   #3
Junior Member
Thread Starter
 
Join Date: Jan 2010
Location: Atlanta GA
Posts: 167
Total Cats: 0
Default

Quote:
Originally Posted by Braineack View Post
Thanks for the link!

If I use that adjustment will I have to convert all my tuning to AFM instead of AFR or can I just use it to calibrate the gauge to match the virtual gauge?

Also, in the link he talks about changing tenths of a point, will this fix work when it's 2-3 whole points?

Last edited by D.dutton9512; 03-22-2010 at 06:52 PM.
D.dutton9512 is offline   Reply With Quote
Old 03-22-2010, 09:38 PM   #4
Elite Member
iTrader: (17)
 
Join Date: Apr 2009
Location: Atlanta, GA
Posts: 2,831
Total Cats: 0
Default

we tried doing this, and have tried pretty much everything to get his AFR's to match up and nothing.....they got closer!

at idle they match up and when you first start out driving they match up, but as you proceed with running the car they begin to venture apart! that and a couple other things that are happening iss we put green top supra injectors in his car witch i belive are 320cc and tried setting up in MT for the injectors and the car started really really bad.........

we are out of ideas.....
WonTon is offline   Reply With Quote
Old 03-23-2010, 12:06 AM   #5
Junior Member
Thread Starter
 
Join Date: Jan 2010
Location: Atlanta GA
Posts: 167
Total Cats: 0
Default

I did some more test tonight and it seems that they really start to separate around 25K RPM in third gear, at the same RPM in fourth gear they're approx 3-4 off, and by the time I'm in fifth they're completely separated with the physical gauge reading 18+ and the Megatune Gauge reading 11-13.

When I bring the car to a stop they slowly start to line up again. And he's right, we've tried everything in that post but it doesn't seem to help this particular problem. I can change the lambda sensor file and change the reading in Megatune but once I hit that spot where they separate it does nothing.
D.dutton9512 is offline   Reply With Quote
Old 03-23-2010, 12:52 AM   #6
Elite Member
iTrader: (7)
 
Join Date: Jan 2007
Location: Renton Washington
Posts: 1,742
Total Cats: 3
Default

Quote:
Originally Posted by D.dutton9512 View Post
I did some more test tonight and it seems that they really start to separate around 25K RPM in third gear, at the same RPM in fourth gear they're approx 3-4 off, and by the time I'm in fifth they're completely separated with the physical gauge reading 18+ and the Megatune Gauge reading 11-13.

When I bring the car to a stop they slowly start to line up again. And he's right, we've tried everything in that post but it doesn't seem to help this particular problem. I can change the lambda sensor file and change the reading in Megatune but once I hit that spot where they separate it does nothing.
What motor are you running that allows you to spin 25,000 revolutions per minuet?
SKMetalworks is offline   Reply With Quote
Old 03-23-2010, 01:19 AM   #7
Junior Member
Thread Starter
 
Join Date: Jan 2010
Location: Atlanta GA
Posts: 167
Total Cats: 0
Default

Wow, looks like I missed some decimal points, sorry about that.

So I just switched the MT software to read "Unknown Wideband" which essentially converts it into a simple volt meter. It looks like at low speeds/rpms the volts are right where they should be but as I gain speed the volts just start to drop regardless of what the gauge is showing. Could this be something wrong within my Megasquirt? It doesn't make sense that the sensor reads fine and gives a good voltage signal at idle and slow speeds, then get's really skewed when it's going along.

Last edited by D.dutton9512; 03-23-2010 at 01:34 AM.
D.dutton9512 is offline   Reply With Quote
Old 03-23-2010, 12:50 PM   #8
Elite Member
iTrader: (17)
 
Join Date: Apr 2009
Location: Atlanta, GA
Posts: 2,831
Total Cats: 0
Default

i hope its not the unit!

it was fine when i parked my car and pulled it! i had the same set up minus what you have under the hood!
WonTon is offline   Reply With Quote
Old 03-23-2010, 02:18 PM   #9
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

Quote:
Originally Posted by D.dutton9512 View Post
Wow, looks like I missed some decimal points, sorry about that.

So I just switched the MT software to read "Unknown Wideband" which essentially converts it into a simple volt meter. It looks like at low speeds/rpms the volts are right where they should be but as I gain speed the volts just start to drop regardless of what the gauge is showing. Could this be something wrong within my Megasquirt? It doesn't make sense that the sensor reads fine and gives a good voltage signal at idle and slow speeds, then get's really skewed when it's going along.
This problem occurs because the AEM's actual output curve does not match its published output curve. To fix it, you would need to map out the unit's voltage output vs AFR at several points and build your own calibration table. I think Joe Perez did this for his.

I've also heard reports that the AEM's error also can drift over time. I don't know if that's true or not.
Ben is offline   Reply With Quote
Old 03-23-2010, 03:09 PM   #10
Elite Member
iTrader: (17)
 
Join Date: Apr 2009
Location: Atlanta, GA
Posts: 2,831
Total Cats: 0
Default

at first we had his Bank 2 O2 censor disconnected, he disconnected the bank 1 in the bay this morning and everything is good now! they match up great!
WonTon is offline   Reply With Quote
Old 03-23-2010, 05:49 PM   #11
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

Quote:
Originally Posted by WonTon View Post
at first we had his Bank 2 O2 censor disconnected, he disconnected the bank 1 in the bay this morning and everything is good now! they match up great!
Are you saying that the narrowband sensor was still installed along side the wideband? Yes, that would be the problem.
Ben is offline   Reply With Quote
Old 03-23-2010, 05:52 PM   #12
Elite Member
iTrader: (17)
 
Join Date: Apr 2009
Location: Atlanta, GA
Posts: 2,831
Total Cats: 0
Default

yeh! at first both were plugged up, then we disconnected the rear and still the prob existed, then he unplugged the front one and now all is well!
WonTon is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
Leaky Wilwoods mx592 Suspension, Brakes, Drivetrain 1 10-01-2015 01:45 AM
1996 Turbo Build Goldwar DIY Turbo Discussion 2 09-29-2015 10:20 AM
wiring wideband ground to battery terminal btabor ECUs and Tuning 10 09-28-2015 06:33 PM


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 01:40 AM.