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Thread: Ultra lean idle until CTS reads 100f

  1. #1
    boostaholic
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    Ultra lean idle until CTS reads 100f

    87 electronics running Rob's Turbonator v13, and otherwise fairly well dialed in. I'm trying to track down a problem where the Daytona starts up fine, but after a few seconds begins to idle super lean at around 19 or 20:1 (or worse) on my gauge until the coolant temp sensor reads about 100 degrees where it will then behave perfectly normal. Before this point it may stall out from being so lean or I have to keep blipping the throttle to keep it alive.

    I've tried adding more to the cold enrichment tables in the area below 100 but it didn't really seem to do anything. Is there someplace else I should be looking?

  2. #2
    Slugmobile & MeanMini Caretaker Turbo Mopar Contributor wheming's Avatar
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    Re: Ultra lean idle until CTS reads 100f

    I'm no expert, so take it fwiw, but i was told to look at my pump efficiency curve for the opposite reason - too rich on cold starts.
    Peftbl is the short name. Its a fuel modifier.
    Wayne H.

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  3. #3
    turbo addict
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    Re: Ultra lean idle until CTS reads 100f

    What size injectors are you using? What injectors scale size are you using?

    I'd make copy of your calibration file, increase the injector size by 40% then copy your all your baseline, part throttle, wot fuel maps over and see if the issue goes awya.

  4. #4
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    Re: Ultra lean idle until CTS reads 100f

    Quote Originally Posted by wheming View Post
    I'm no expert, so take it fwiw, but i was told to look at my pump efficiency curve for the opposite reason - too rich on cold starts.
    Peftbl is the short name. Its a fuel modifier.
    You may be on to something. I was having the same problem this summer so I took a big chunk out of the peftbl below 1500rpm, but the car was always warmed up when i was adjusting it. Maybe I should add some back there.

    - - - Updated - - -

    Quote Originally Posted by tryingbe View Post
    What size injectors are you using? What injectors scale size are you using?

    I'd make copy of your calibration file, increase the injector size by 40% then copy your all your baseline, part throttle, wot fuel maps over and see if the issue goes awya.
    52pph injectors scaled as such. If tweaking my peftbl down low doesnt fix it I'll give this a shot.

  5. #5
    Slugmobile & MeanMini Caretaker Turbo Mopar Contributor wheming's Avatar
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    Re: Ultra lean idle until CTS reads 100f

    Add back about half of what you took out, and try a cold start.
    That will tell if you in the right track. Then take a bit out at a time if still too rich.
    Wayne H.

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  6. #6
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    Re: Ultra lean idle until CTS reads 100f

    Just tried that. I added about 20% to the PE table under 1500rpm and it didn't change at all.

    Initial startup it idles up to it's cold idle speed and is slightly rich or near stoich.

    after a few seconds it starts to lean out until it reaches 22:1 indicated and stalls.

    When I restart it will usually stay running, but is rough and still around 20:1.

    I'm using the narrowband sim output off my Innovate to feed the logic module.

    MPScan shows the o2 sensor input toggling as expected.

    By the time I got though this list the CTS was reading over 100 so it started behaving. I'll try a new cal file with my fuel tables later tonight after it cools off again.

  7. #7
    Visit www.boostbutton.com... Turbo Mopar Contributor ShelGame's Avatar
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    Re: Ultra lean idle until CTS reads 100f

    That doesn't make sense. If the O2 sensor value is toggling, that means it's bouncing around 14.7 AFR. Are you sure your NB output is setup right?
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  8. #8
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    Re: Ultra lean idle until CTS reads 100f

    You're right that doesn't make sense. I must have noted something incorrectly. My brain has been fried the past few weeks dealing with a newborn, so forgive me.

    One of these days I'll get back out there mess with it again.

  9. #9
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    Re: Ultra lean idle until CTS reads 100f

    So the fix was to add some back to the PE table at idle.

    However, now it does this thing where the startup idle is crazy low and it will sometimes die. It's around 400 or so. if I blip the throttle a few times It eventually goes up to the correct warmup idle speed and then slowly comes down to the hot idle speed as it gets up to temp. Not sure where to start looking for that. I tried bumping the starting AIS position up some but it didnt seem to help much. Also set and reset the idle speed screw about a million times.

  10. #10
    turbo addict
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    Re: Ultra lean idle until CTS reads 100f

    There should be 3 cold or temp related fuel tables. Been years since I looked at them and even opened my laptop for it. They were labled correctly in the old S60 cal and transfered over to the newer stuff if you knew what you were looking at. 100f is the key as that's where the switch point is/was. I'd have to take a couple hours to look for my laptop and find all that stuff again.

  11. #11
    Moderator Turbo Mopar Staff Force Fed Mopar's Avatar
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    Re: Ultra lean idle until CTS reads 100f

    People need to stop trying to fix every fueling problem with the PumpEff table...smh... Cold Enrichment Curve A is what it starts up on, then runs on Curve B after a few secs until it warms up some. Not quite sure where Curve B stops and Curve C starts. I have rarely ever had to adjust Curve C though.

    It basically should go like this: if the fueling gets richer or leaner as rpm increases, adjust PumpEff. If it stays the same through the rpm range but is rich or lean, adjust the WOT or part-throttle from map tables. Rich/lean on start-up or warm-up, adjust the Cold Enrichment Curve tables. This will get you 90% of the way to proper fueling. After that you can tweak the prime, pump shot, baseline from map, etc etc to get things just right for your combo.
    Rob M.
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  12. #12
    Boost, it's what's for dinner... Turbo Mopar Staff Aries_Turbo's Avatar
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    Re: Ultra lean idle until CTS reads 100f

    my reliant is doing the same thing right now.

    you get the pumping efficiency correct once temps are stabilized.

    then you tune cold start. curve C has the shortest effect. A has a longer effect and is different if the engine is cold or hot (~120 deg switch point)

    curve B is in effect all the time i believe.

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

  13. #13
    Visit www.boostbutton.com... Turbo Mopar Contributor ShelGame's Avatar
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    Re: Ultra lean idle until CTS reads 100f

    Maybe we can convince Morris to make another 3d calculated table. In the SBECII cals, the ABC curves are a 3d table with temp and time as the input axes. We could show the A, B, C curves and decay times as a 3d table, I would think...


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    Moderator Turbo Mopar Staff Force Fed Mopar's Avatar
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    Re: Ultra lean idle until CTS reads 100f

    I think we need a proper description of what exactly those 3 ColdEnrichment tables do and when, as we all seem to have a different understanding of it at the moment lol.
    Rob M.
    '89 Turbo GTC

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    Boost, it's what's for dinner... Turbo Mopar Staff Aries_Turbo's Avatar
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    Re: Ultra lean idle until CTS reads 100f

    http://www.turbo-mopar.com/forums/sh...l=1#post132030

    here is robs flow charts for the 89t1 stuff.

    im still not 100% sure what "hold" time means.... if its hold on (ie enrichment table in effect) or hold off (ie enrichment table not in effect)

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

  16. #16
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    Re: Ultra lean idle until CTS reads 100f

    Quote Originally Posted by ShelGame View Post
    Maybe we can convince Morris to make another 3d calculated table. In the SBECII cals, the ABC curves are a 3d table with temp and time as the input axes. We could show the A, B, C curves and decay times as a 3d table, I would think...


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  17. #17
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    Re: Ultra lean idle until CTS reads 100f

    Without looking, I'm guessing hold ON as there is also a decay time that presumably is the fade to nil after the hold timer expires in the LM stuff.

    Quote Originally Posted by Aries_Turbo View Post
    http://www.turbo-mopar.com/forums/sh...l=1#post132030

    here is robs flow charts for the 89t1 stuff.

    im still not 100% sure what "hold" time means.... if its hold on (ie enrichment table in effect) or hold off (ie enrichment table not in effect)

    Brian

  18. #18
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    Re: Ultra lean idle until CTS reads 100f

    Quote Originally Posted by iangoround View Post
    Without looking, I'm guessing hold ON as there is also a decay time that presumably is the fade to nil after the hold timer expires in the LM stuff.
    thats what ive always thought but i threw it out there just in case i was wrong.

    it seems to work that way too. mine will start nice and rich and smooth and then after a set time starts the warmup burble idle hunt and then smooths out once warm.

    once i get my car inspected ill have to take it for a ride and get good and warm and set the pumping efficiency and play with warmup some more.

    i also would like to limit some of the o2 feedback at idle. i dont care if it sits and idles at 13.9:1 if its smooth and steady.

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

  19. #19
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    Re: Ultra lean idle until CTS reads 100f

    Some progress. I readjusted the base idle screw. It was set too low. Also added a little bit prime shot, and cold enrichment tables.

    It starts up nicely now, but after about 20 seconds it starts to lean out too much and stumbles. I'll have to mess with it more today. It's tough because once the engine is warm it starts right up and behaves nicely. I only have about 60 seconds of running time before its up to a warm enough temp to not exhibit the problem.


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  20. #20
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    Re: Ultra lean idle until CTS reads 100f

    Quote Originally Posted by iangoround View Post
    Some progress. I readjusted the base idle screw. It was set too low. Also added a little bit prime shot, and cold enrichment tables.

    It starts up nicely now, but after about 20 seconds it starts to lean out too much and stumbles. I'll have to mess with it more today. It's tough because once the engine is warm it starts right up and behaves nicely. I only have about 60 seconds of running time before its up to a warm enough temp to not exhibit the problem.


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    Did you ever fix this issue? I have the same problem.

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