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tuning in open loop with wide band

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Old Jan 21, 2008 | 06:56 PM
  #1  
spacgost79's Avatar
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From: stamford ct.
Car: 88 iroc-z
Engine: 5.7 zz4
Transmission: megaraptor 700r4
Axle/Gears: 3.73 10 bolt posi
tuning in open loop with wide band

just need to make sure i am doing this correctly, with 165 6e maf set up,
#1 disable closed loop by changing enable temp #2 clear learned blms by disconnecting batt #3 change maf tables to get a/f ratio to 14.7 at idle and cruising ( a/f ratio is extreamly lean in open loop, and blms are pinned at 160 in closed loop) full trottle accel is good at 12.8-12.2 a/f ratio......am i understanding this correctly???? PLEASE anybody correct me if i am WRONG!!
any suggestions are definetly WELCOME, using an AEM wide band kit and a snap on scanner so i can monitor all engine functions, ANY and ALL help is welcome thanks guys
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Old Jan 21, 2008 | 07:16 PM
  #2  
RBob's Avatar
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From: Chasing Electrons
Car: check
Engine: check
Transmission: check
Re: tuning in open loop with wide band

The only area I see that may not be correct is #3 "change maf tables to get a/f ratio to 14.7 at idle and cruising"

The ECM may or may not be commanding 14.7:1 in open loop idle and cruise. What I usually do is to log the commanded AFR along with the WB reported AFR, and make changes to the MAF tables to have them match up. Of course the open loop AFR tables/adjustments can be changed so that the ECM always commands 14.7:1, but I don't know if that has been done.

May also want to disable the DTC 13, 44, & 45 codes. Else the ECM may light the SES which is bothersome.

RBob.
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Old Jan 21, 2008 | 08:57 PM
  #3  
spacgost79's Avatar
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Joined: Dec 2004
Posts: 50
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From: stamford ct.
Car: 88 iroc-z
Engine: 5.7 zz4
Transmission: megaraptor 700r4
Axle/Gears: 3.73 10 bolt posi
Re: tuning in open loop with wide band

i am planing on changing the ecu back to closed loop after tuning,what im tring to do get the base tune closer to a "proper or normal" tune because the stock tune is so far off the car runs very poorly in open loop and the a/f ratio is so lean that the w/b will just go to --- which is leaner than a/f 16:1..so if i can get the open loop tune at least to 14 - 13 a/f and use the ecu in closed loop than the ecu can do its job and if there is faults the ses light comes on the car will still be driveable in open loop to get home. PLEASE correct me if i am WRONG, im still tring to learn
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Old Jan 21, 2008 | 11:49 PM
  #4  
RBob's Avatar
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From: Chasing Electrons
Car: check
Engine: check
Transmission: check
Re: tuning in open loop with wide band

You are not wrong in what you are trying. Although if you need to rough in the tune it would be better to leave it in closed loop. That way the INT/BLM can adjust and the engine will stay running. Then use the BLM value to adjust the MAF tables.

Then once the tune (AFR wise) is closer go to open loop with the WB vs Commanded AFR. Get the MAF tables closer more quickly. Then back to closed loop for the final settings.

RBob.
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Old Jan 24, 2008 | 04:55 PM
  #5  
spacgost79's Avatar
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Joined: Dec 2004
Posts: 50
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From: stamford ct.
Car: 88 iroc-z
Engine: 5.7 zz4
Transmission: megaraptor 700r4
Axle/Gears: 3.73 10 bolt posi
Re: tuning in open loop with wide band

can you please explain the "actual a/f vs commanded" i am using tunerpro rt
and dont i dont seem to have any table with comanded a/f. its too cold to play with the car now i am trying to read up and understand as much as possible before the spring time ! i figured it would be easier to tune in open loop since the ecu wont be changing fueing but i will try any proven methed i am open to all suggestions, since the car is extremly lean i have changed the closed loop temp to 80* to allow the ecu to add fuel since i didnt want to change any tuning until i understand what i am doing, THANK YOU for your help
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Old Jan 26, 2008 | 10:58 AM
  #6  
IROCZ28dan's Avatar
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Joined: Dec 2003
Posts: 236
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From: Vineland, NJ
Car: 1987 IROC-Z
Engine: 350 TPI
Transmission: 700R4
Re: tuning in open loop with wide band

In tunerpro if you go to the setup menu and choose whatever log file you wish to view, you can select export file to csv and then open it in excel or something similar. From there, you will have a column that has commanded AFR. just a tip for you.
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