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Thread: $EE / LT1 Injector Swap Running Rich

  1. #46
    Fuel Injected! Terminal_Crazy's Avatar
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    Quote Originally Posted by spfautsch View Post

    For whatever reason, this gets things into the opposite of a "goldilocks zone" between 135F and 144F where it wants to "meow" to life. It's starting reliabily here now with one crank so I'm going to move on to bigger and better things, but oddly if you start it at this temp and then shut it off within 1-2 seconds it will restart eagerly (presumably because the valves have been warmed). At ECT above 144 or below 135 it seems to roar to life as it did with stock injectors. Even warmer and cooler ECTs (above 146F or below 133F) are much more forgiving of AFR at startup. You have to take a ton of fuel out to get any reaction in these ranges.
    I just happened to come across this post whilst searching.
    This is very similar to my issue with injectors going lean and happened at 49C to 55C. Your temps are around 56C-63C
    Scott, could you check your logs to see if the injectors were leaning out at these temps?

    Thanks
    Mitch
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

  2. #47
    Fuel Injected! spfautsch's Avatar
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    I would but I don't think I have any logs of bringing the car up to temp at idle with the big injectors. I'll try to make one for you today if I get a chance.

    I don't really think my issue is related but it could be. The pulsewidth I ended up at for the 56C row that was giving me the most problems was 2.23ms which I think is a bit higher than where you're seeing your O2s "flatline"?

    It's been nasty cold here the last week or so. I've been freezing my behind off working on the diy-ltcc controller with the garage door open so the fumes don't asphyxiate me.

  3. #48
    Fuel Injected! spfautsch's Avatar
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    Here's a log of 11c - 73c at idle w/ ~43.5lb injectors. Definitely not seeing an O2 flatline issue like yours, but maybe there's something else that's useful to you here. Closed loop MAF tune btw.

    Sorry it took so long to get this - had to spend yesterday keeping the rest of the "fleet" roadworthy as well as fixing the clothes washer. We have a saying here - if momma ain't happy, ain't nobody happy.
    Attached Files Attached Files

  4. #49
    Fuel Injected! Terminal_Crazy's Avatar
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    Cheers for that.

    Is your wideband hooked up ?

    It never moves, 9.32 when cold to 9.44 @73C
    O2's look similar to mine. I know they are cold upto 11C there are two straight lines upto 650/750mV.
    Then they start oscillating and drop down to 50/60mV at 42C
    At 44C they've picked back up to 850/900mV until 60C when they go CL.
    The LHS has a much more stable reading & the RHS has a much wider range.
    Still it's around the 42-44 Degree mark that they choke.
    Maybe they flash off once they start warming up ???

    Maybe mine aren't doing anything weird.

    I'm hoping the new ones will arrive tomorrow.

    Cheers anyway
    Mitch
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

  5. #50
    Fuel Injected! spfautsch's Avatar
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    No wideband - that's my A/C changing pressure as the engine compartment warms up. I doubt I will invest in one, but if I do it will be several months off.

    I don't honestly pay much attention to what the O2s are doing when brought to temp idling. I generally start logging when I start it up, put it in gear and drive. As I mentioned earlier in this thread they act wholly different when brought up to temperature with load on the engine.

    The right bank has shown fewer cross counts from day one, but it's gotten worse since the injector swap. I believe individual cylinder trims may have something to do with this.

  6. #51
    Fuel Injected! Terminal_Crazy's Avatar
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    That explains the stable afr then ��

    Mitch
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

  7. #52
    Fuel Injected! spfautsch's Avatar
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    Another thing just occurred to me that will affect how my O2s are measuring at startup - air injection. Mine is fully functional. Sorry I didn't think about this sooner.

  8. #53
    Fuel Injected! Terminal_Crazy's Avatar
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    I binned mine off years ago when I swapped the exhaust manifolds.

    Mitch
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

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