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Thread: o2 questions with chrome

  1. #1

    o2 questions with chrome

    I've done alot of reading and would like some more up to date opinions.
    I have chrome v2 on my 92. 92 3KGT VR4 13T Turbos w/ 9psi springs, DR SMIC's, SPEC Stage III clutch, 25 Spline Tranny, 560CC Injectors, LS6 MAF-T, Dejon Split Ypipe, Custom 3" dual intakes, Walbro 255w/ re-wire, Greddy e-manage w/ timing control, ATR Downpipe, Straight pipe exhaust, Test Pipe, Hallman MBC, 3rd gen lifters, Maximal Performance solid motor/tranny mounts, Autometer Water temp, Boost, EGTx2, Elec oil pressure gauges, Innovate LC-1 wideband, HKS ssqv BOV, Megan lowering springs, Keyless push button start, LED interior light swap, Blackstealth LCD logger, 3sx 2" core radiator, 2pc aluminum driveshaft, Solid rear diff bushings, Jester ECU

    Thats my mod list to give a better idea of what I'm working with.

    Basically some times I fire up and my idle is good and some times(usually cold) it runs rich as balls and refuses to change with tuning the fuel map. From what I can tell via the logs it is an open/close loop problem. I only run the rear narrowband as the front took a dump years ago(yes I have chrome set to use just the back.) I know the rear is old and maybe it being slow is my problem. I have my wideband in the downpipe and wired to chrome for logging. There are several options and I would like the best most consistent one to be my solution. I've read debates on each one but never found good answers for any of them.

    1)Unplug both narrowbands and run just the wideband essentially running open loop indefinetly.

    2)Simulate a narrowband off the wideband thus having the ecu read it from the downpipe(which I read causes tuning issues for ecu)

    3)I thought 3rd gen had a wideband sensor so why can't we use a wideband and run it properly with open and close loop in place of narrows? Again does sensor location make that a bad idea?

    4)I understand running constant open loop has many downfalls unless I'm mistaken?? Tune drift, weather, etc

  2. #2
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    What about replacing the oxygen sensors and tuning it with closed loop working how it's intended? Also, on a cold start it will run rich until it warms up... that's why there are cold start tuning tables.
    1995 Dodge Stealth R/T Turbo
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  3. #3
    There's that option(being the most expensive lol) But with all this new lovely stuff I'd like to go beyond relying on those. Should I just try adjusting the cold start tables or just let it run rich as hell until its warm and just deal with the smaller inconsistencies after that?
    Last edited by abomboldskool; 09-16-2014 at 02:22 PM.

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    Quote Originally Posted by abomboldskool View Post
    I've done alot of reading and would like some more up to date opinions.
    I have chrome v2 on my 92. 92 3KGT VR4 13T Turbos w/ 9psi springs, DR SMIC's, SPEC Stage III clutch, 25 Spline Tranny, 560CC Injectors, LS6 MAF-T, Dejon Split Ypipe, Custom 3" dual intakes, Walbro 255w/ re-wire, Greddy e-manage w/ timing control, ATR Downpipe, Straight pipe exhaust, Test Pipe, Hallman MBC, 3rd gen lifters, Maximal Performance solid motor/tranny mounts, Autometer Water temp, Boost, EGTx2, Elec oil pressure gauges, Innovate LC-1 wideband, HKS ssqv BOV, Megan lowering springs, Keyless push button start, LED interior light swap, Blackstealth LCD logger, 3sx 2" core radiator, 2pc aluminum driveshaft, Solid rear diff bushings, Jester ECU

    Thats my mod list to give a better idea of what I'm working with.

    Basically some times I fire up and my idle is good and some times(usually cold) it runs rich as balls and refuses to change with tuning the fuel map. From what I can tell via the logs it is an open/close loop problem. I only run the rear narrowband as the front took a dump years ago(yes I have chrome set to use just the back.) I know the rear is old and maybe it being slow is my problem. I have my wideband in the downpipe and wired to chrome for logging. There are several options and I would like the best most consistent one to be my solution. I've read debates on each one but never found good answers for any of them.

    1)Unplug both narrowbands and run just the wideband essentially running open loop indefinetly.

    2)Simulate a narrowband off the wideband thus having the ecu read it from the downpipe(which I read causes tuning issues for ecu)

    3)I thought 3rd gen had a wideband sensor so why can't we use a wideband and run it properly with open and close loop in place of narrows? Again does sensor location make that a bad idea?

    4)I understand running constant open loop has many downfalls unless I'm mistaken?? Tune drift, weather, etc
    you may be flooding it a bit if you are running the stock cranking IPW. I would multiply the values in the cranking IPW table by .75 and see what that does for you. It may start better too. The injector scalings are ignored when cranking.

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  5. #5
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    If what Forest stated does not work check that the front/rear O2's are not wire backwards. This has been a mistake in a few, including mine.

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  6. #6
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    Fix the front o2.

    Who said 3rd gens have a wideband?? They are wrong.

    Dial back the coolant temp enrichment. That table is in the fuel section.

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  7. #7
    Thought I had remembered reading that they had a wideband. I was wrong. I did raise the enrichment a bit. Someone informed me that mid 12 AFR was correct until warm?

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