Go Back   EcoModder Forum > EcoModding > Instrumentation
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 07-01-2010, 11:55 AM   #1 (permalink)
EcoModding Lurker
 
Join Date: Jun 2010
Location: Trondheim, Norway
Posts: 14

CGVES - '99 Chrysler Grand Voyager ES
Thanks: 0
Thanked 0 Times in 0 Posts
ScanGauge II does not show open loop under DFCO?

Hi

my SGII does not show open loop (and hence not 0.0 l/100km) during DFCO. I can tell the vehicle does have DFCO ('99 Chrysler Grand Voyager, 2.4L 4speed AT), both "manually" by watching the tacho during decel, and by the XGauge O2-program as it shows 0 or 2 during DFCO, else it bounces around between 20-90.

Throttle position is 16-17 when I'm off the pedal, and the SGII DFCO threshold is at 24 (default).

Sometimes, if not always (not sure) when I lift off the throttle, the display shows OPEN LP and 0.0 LHK for a split second, before it goes back to CLSD LP and ~2-3 LHK. The O2 drops to ~0 and stays there.

It is always OPEN LP at full throttle accel.

Is there any way to "force" the SG to sense DFCO, or correct this in any way?
Or maybe my assumtion that the car does DFCO is wrong?

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 07-01-2010, 04:43 PM   #2 (permalink)
Dartmouth 2010
 
SVOboy's Avatar
 
Join Date: Nov 2007
Location: Hanover, NH
Posts: 6,447

Vegan Powa! - '91 Honda CRX DX
Team Honda
90 day: 66.52 mpg (US)
Thanks: 92
Thanked 122 Times in 90 Posts
Send a message via AIM to SVOboy Send a message via MSN to SVOboy Send a message via Yahoo to SVOboy
Does it also report the vehicle as using fuel during this time? It might be that your assumption of DFCO is incorrect, but I don't know enough about the specific model to comment on that.
  Reply With Quote
Old 07-02-2010, 06:47 AM   #3 (permalink)
EcoModding Lurker
 
Join Date: Jun 2010
Location: Trondheim, Norway
Posts: 14

CGVES - '99 Chrysler Grand Voyager ES
Thanks: 0
Thanked 0 Times in 0 Posts
Yes, it reports a fuel usage of ~2.5 l/100km at ~80 kmh (that's ~94 MPG at ~50 MPH).

From what I've heard, the fuel usage is calculated from air flow to the engine, so SGII will show a fuel usage even if the injectors are off, as long as it does not assume DFCO (from open loop and throttle closed). Is this correct, or have I misunderstood something?
  Reply With Quote
Old 07-02-2010, 09:39 AM   #4 (permalink)
Pokémoderator
 
cfg83's Avatar
 
Join Date: Dec 2007
Location: Southern California
Posts: 5,864

1999 Saturn SW2 - '99 Saturn SW2 Wagon
Team Saturn
90 day: 40.49 mpg (US)
Thanks: 439
Thanked 530 Times in 356 Posts
Pappnese -

My car does the same thing. I know this because I have a digital Air/Fuel Ratio gauge. I can "see" the 02 sensor go lean, but the scangauge is still reporting closed-loop.

My theory is that this behavior is OBDII compliant. The ECU/PCM initiated fuel cutoff and continues to report closed-loop operation because it is in full control, aka it knows *why* the 02 sensor is reporting a lean condition and that's ok. In fact, it's good because it's proof that the DFCO is functioning.

If you think about it, the other sensors might report values that are also tainted by DFCO, so why go into open-loop at all?

CarloSW2
__________________

What's your EPA MPG? Go Here and find out!
American Solar Energy Society
  Reply With Quote
Old 07-02-2010, 10:01 AM   #5 (permalink)
dcb
needs more cowbell
 
dcb's Avatar
 
Join Date: Feb 2008
Location: ˙
Posts: 5,038

pimp mobile - '81 suzuki gs 250 t
90 day: 96.29 mpg (US)

schnitzel - '01 Volkswagen Golf TDI
90 day: 53.56 mpg (US)
Thanks: 158
Thanked 269 Times in 212 Posts
this is an instance where some manufacturers will do something differently than others. What to report to the obd II port in this instance probably wasn't viewed as terribly critical or was otherwise ambiguous.
__________________
WINDMILLS DO NOT WORK THAT WAY!!!
  Reply With Quote
Old 07-02-2010, 03:43 PM   #6 (permalink)
EcoModding Lurker
 
Join Date: Jun 2010
Location: Trondheim, Norway
Posts: 14

CGVES - '99 Chrysler Grand Voyager ES
Thanks: 0
Thanked 0 Times in 0 Posts
You guys are probably right, that my car does DFCO, but doesn't report open loop when it does.

Any workaround to get the ScanGauge to report 0 fuel usage while DFCO then? Or is this impossible, or maybe we have to wait for an firmware upgrade?
  Reply With Quote
Old 09-06-2010, 04:47 AM   #7 (permalink)
EcoModding Lurker
 
Join Date: Sep 2010
Location: stone mtn ga usa
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Have you tried setting the SGII DFCO threshold to 18?

  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Scangauge II vs cruise control rjacob Instrumentation 10 06-02-2011 02:36 PM
Time from open loop to closed loop... BamZipPow EcoModding Central 7 01-31-2010 08:45 AM
How long should an engine stay in open loop after start bombloader Hypermiling / EcoDriver's Ed 4 12-11-2009 06:32 PM
Closed loop / open loop bogging down... markweatherill Off-Topic Tech 3 09-28-2009 09:42 PM
My car is too eager to switch to open loop RobertSmalls EcoModding Central 3 01-23-2009 12:51 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com