No Closed loop???

+ Reply to Thread
Results 1 to 12 of 12
  1. #1
    Member Array TTS281's Avatar
    Join Date
    Jun 2007
    Location
    Roswell, NM
    Posts
    57

    Default No Closed loop???

    I have a 96 cobra with d1 etc. anyways It has been tuned with diablo chip, but I have drivability issues. When watching the scan tool I noticed the car never goes into closed loop and the o2 heaters are always on? There is no short term or long term fuel trim.
    I have replaced the 02 and the temp sensor those were the 2 things I was told determined closed loop. Any ideas would be appreciated?

    Also I have removed the chip from the car and it still never goes closed loop?

  2. Remove Advertisements
    ModularFords.com
    Advertisements
     

  3. #2
    Premium Member Array Eric Brooks's Avatar
    Join Date
    Oct 2002
    Location
    Eastpoint, FL
    Posts
    19,254

    Default

    Alot of Diablo dealers force the cars into open loop like that. For one it prevents the car from ever throwing 02 codes (rich/lean).

    Are you positive, the PCM does not have an aftermarket tune flashed in?

  4. #3
    VMP Tuning Array Justin@VMP's Avatar
    Join Date
    Feb 2004
    Location
    Central FL
    Posts
    2,911

    Default

    Some of those older cobra cars do weird things with closed loop (IE won't go into it) if the fuel trims are too far off.

  5. Remove Advertisements
    ModularFords.com
    Advertisements
     

  6. #4
    Member Array TTS281's Avatar
    Join Date
    Jun 2007
    Location
    Roswell, NM
    Posts
    57

    Default

    Quote Originally Posted by Eric Brooks View Post
    Alot of Diablo dealers force the cars into open loop like that. For one it prevents the car from ever throwing 02 codes (rich/lean).

    Are you positive, the PCM does not have an aftermarket tune flashed in?
    Yes, stock I also had the computer reflashed today at the dealer same thing no change.

    Quote Originally Posted by [email protected] View Post
    Some of those older cobra cars do weird things with closed loop (IE won't go into it) if the fuel trims are too far off.
    What do you suggest I do. I have a wideband and when tunned corectly it missed really bad drivability wise wide open is always good. it is set up rich right now because it helped the missing but they told me without short terms they had to add fuel all the way across the map. right now A/F is 13.0 wide open 11.8 any help appreciate the reflash was the last thing I knew to do.

  7. #5
    Premium Member Array Eric Brooks's Avatar
    Join Date
    Oct 2002
    Location
    Eastpoint, FL
    Posts
    19,254

    Default

    All of the other sensors look ok when logging? Throttle Position, Coolant Temp, etc?

  8. #6
    Member Array TTS281's Avatar
    Join Date
    Jun 2007
    Location
    Roswell, NM
    Posts
    57

    Default

    Quote Originally Posted by Eric Brooks View Post
    All of the other sensors look ok when logging? Throttle Position, Coolant Temp, etc?
    Yes I can watch all sensors - tp--- coolant climbs to 180-- the o2 even show up the short and long terms are just 0. there is no codes in the computer other than the normal egr rear o2's IMRC's(deleted) and these codes are only present with the chip removed.

  9. #7

    Default

    I have a 97 Cobra and some of the SCT logging data is incorrect. For example, my open loop flag does work or log correctly. The Load vs AFR table for open loop only works on about 3 loads and the other load values in the chart it just skips. There is a table for RPM VS LOAD at open loop that doesn't work right... etc... you just have to find out the bugs and work with them. I know there are a few Short Term Fuel logging items in the PCM and if your logging the wrong one it will show a "0". If your logging the correct one it will float around 1 or so in CL and when OL jump down to the commanded lamda value.... (.82, .78, etc)

  10. #8
    Banned Array
    Join Date
    Nov 2006
    Location
    Longwood, FL
    Posts
    140

    Default

    I have seen several 96-98 cobras fail to go closed loop because the thermactor system fails. If it is pumping air upstream, the PCM will leave the car open loop. For some reason, this usually will not throw a CEL. I will usually turn off the switch in the tune to confirm it, but you will probably just have to diag it old school.

    The better way to datalog open closed loop is with Fuel Source. The open closed loop flag is not always active or accurate in a ford PCM, so we have become accustom to using fuel source. It will also let you know if you are running normal open loop or cold startup open loop (very useful).

    James

  11. #9
    Senior Member Array
    Join Date
    Oct 2003
    Location
    Miami, FL
    Posts
    167

    Default

    James is correct, if the termactor system has failed or has been removed, the EEC will stay in open loop. The thermactor can be turned off, have your tuner do so just for giggles, even if he's forced open loop.

  12. #10
    Member Array TTS281's Avatar
    Join Date
    Jun 2007
    Location
    Roswell, NM
    Posts
    57

    Default

    Thanks I will have them try that --I did remove the termactor system

  13. #11
    Member Array TTS281's Avatar
    Join Date
    Jun 2007
    Location
    Roswell, NM
    Posts
    57

    Default

    Sorry, for the delay car has been at paint. Thank You for the input I turned off the thermactor and instantly went to closed loop. Thanks again

  14. #12

    Default Also no closed loop

    I have the same issue. I do have a tune on it as well, an SCT. I occasionally get a message saying it won't go into closed loop due to temperature not getting hot fast enough, or engine load issue. Tuner states that it's not in the tune but I know he did alter the fans on/off so wondering if that change to the computer has it freaking out. I do have a lower temp thermostat, maybe a 160 or a 170. New O2 sensors all around. It shows fuel trims for just a few seconds then cuts off and goes into open loop failure. I'm concerned that my fuel trims are off and may be lean or rich. I do also have a delayed warm start. 96 cobra bottom end with forged pistons/rods 9:5:1, 2003 Terminator heads, 2001 Cobra intake. Runs good but has a little miss about 3000 rpm. No other codes than the closed loop failure.

  15. Remove Advertisements
    ModularFords.com
    Advertisements
     

+ Reply to Thread

Similar Threads

  1. Closed loop Open loop?
    By BTPJG in forum 2003 - 2004 Mach 1 Mustang
    Replies: 31
    Last Post: 07-13-2011, 09:11 PM
  2. the closed loop fuel system
    By FUELEFFIENCY in forum New Member Introductions
    Replies: 2
    Last Post: 11-24-2007, 07:00 AM
  3. Tuning, O2 sensors, and closed loop
    By Slider1385 in forum Tuning and Diagnostics
    Replies: 18
    Last Post: 04-18-2007, 02:36 PM
  4. Definition of Closed Loop vs Open Loop
    By Boosted98GT in forum Tuning and Diagnostics
    Replies: 20
    Last Post: 02-20-2007, 03:18 PM
  5. Predator and closed loop operation
    By PhillyCobra in forum 2003 - 2004 SVT Mustang Cobra
    Replies: 3
    Last Post: 10-08-2003, 09:51 PM