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Vince's TBI woes, progressive revelations, and tbi mods.

Discussion in 'TBI & EFI Conversions' started by Vbb199, Oct 21, 2020.

  1. Vbb199

    Vbb199 B-rate Hillbilly Customs

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    Youre spot on.
    Didnt even think about more....
    Volatile? Conditions since its colder

    Cold air make engine go boom boom harder


    Gonna give it a go tomorrow.....been working....


    No work tomorrow!
    Will also be checking dizzy to see if its a wore out biatch
     
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  2. Rusty Nail

    Rusty Nail Re-Re-Elect TRUMP 2024

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    Maybe some genius will elaborate the difference (s) between winter and summer fuels. :shrug:
    Surely consideration is given to richer mixtures (i.e. "choke" operations, etc. - If I knew id say.

    I really liked the weak coil under max load idea too. That happens for sure. AND it's hard to diagnose..
     
  3. Vbb199

    Vbb199 B-rate Hillbilly Customs

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    Dizzy is getting replaced no matter what.
    It was on my agenda for upgrades.
    As well as coil.
    Its already ordered and will arrive tuesday
     
  4. 1987 GMC Jimmy

    1987 GMC Jimmy Automobile Hoarder

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    Ahh, there’s my soapbox. So if you had a scan tool and looked at the serial data in real time, you could watch the knock counts and see if it’s going crazy or not so much. Ideally, it’ll knock a couple times at startup, figure it out after a few seconds, and adjust accordingly. The self-test comes a little later as you’ve experienced.

    It may have one or two once in a while, but if it’s doing it pretty constantly, you could run with that. Obviously, that’s after your distributor is nice and tight. You’d then have to adjust timing back or mute the knock sensor as suggested. I don’t know about them being overly sensitive, but I’m not doubting it. Still, though. You’re running 91 octane, which should be fine for a 10.5:1 engine even with a respectable base setting. Maybe it’s time to upgrade to 100LL Avgas.
     
  5. Vbb199

    Vbb199 B-rate Hillbilly Customs

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    My personal opinion, while fucking with the knock sensor is a good idea and probably 40%of the problem, i think its just masking a deeper issue, the worn out dist.

    The issue is rapidly getting worse, and so is the power, Im having random misses on cold cranking now,

    the knock sensor would set 1 standard condition, and that be what it is. The decrease in power wouldnt worsen

    When the engine temp is still below the thermostat opening , while i dont peg the go fast pedal, i feel the power.

    The problems only really show up once its at operating temp and ive been driving it for a bit.


    Imo, its......STILL.....a 33x,xxx distributor from 1989 with worn out bearings.
    Timing IS advanced a couple degrees.

    Its evident when i pull a load behind the truck , it (used to) spark knock under WOT.

    New dist will get a safer adjusted timing


    By the way, as far as the sensitivity, hold a timing light on the dampener and have a buddy lightly tap the block with a hammer (LIGHTLY), if the knock sensor is working correctly, itll pick it up and retard timing.
     
    Last edited: Oct 24, 2020
  6. 1987 GMC Jimmy

    1987 GMC Jimmy Automobile Hoarder

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    I agree, distributor is public enemy number one at this point. Anything else is just kinda riding the coattails of that.
     
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  7. Vbb199

    Vbb199 B-rate Hillbilly Customs

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    I failed to add, i would imagine ^this^ gets into MAP readings, with density of air at different ambient temps outdoors.

    Those map readings changes the AFR to probably a richer condition (If i had to guess)


    I might be wrong, i just know a MAP is what sets the difference in a carb and a basic tbi.... no need for rejetting at different sea levels thanks to MAP.
     
  8. Vbb199

    Vbb199 B-rate Hillbilly Customs

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    Okays..... so theres this





    Pretty sloppy.

    ALSO! I remembered i already own a igintion box and super coil to go with it, direct plug and play in the tbi.


    I FINALLY got tracking for my prom chip as well.....
    (I was getting suspicious)

    After new dizzy, prom, ignition box + regap..... betcha she'll be a nasty mf
     
  9. shiftpro

    shiftpro Full Access Member

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    I just thought of another dizzy issue... I went through this last spring.
    The power lead that plugs in to the dizzy... well it was really worn out and very loose. My power to the dizzy was there but some shorting and weak connection would result in hard starting... until it didn't start anymore. I cleaned and pulled the contacts out a bit (inside the plug, power side) and I was rolling again.
    Just another experience to share here. Just because there is power at the lead don't assume it's feeding the dizzy it's full uninterrupted voltage.
     
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  10. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    does your truck show live data? Im not sure if your crate uses factory HEI or whatever.
    what im saying, is, if you have obd 1 interface and a way to read data, have you checked your computers ignition advance according to computer? Like, tech 1 or tech 2, how much advance in degrees or retard (negative advance) my uncles 95 van allowed me to see what the computer said/thought. I wanna say off-the-line it was sluggish but it was perfect in the high end, his advance while cruising was 12-22 degrees unadjusted according to the computer.

    if you have any other gm vehicles post 1991 and pre 2014 i highly recommend a tech 2
     
  11. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    Wanna see the ignition coil on my f150? or the old coil pack for my park avenue? they would give your cap a run for its money lol

    Oh the worst was the ignition coil bolts for my old saturn sw2
     
  12. Vbb199

    Vbb199 B-rate Hillbilly Customs

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    It uses computer controlled advance.

    Theres no weights or vac advance.
     
  13. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    no what im saying is, can you check what the computer is saying the advance is? then confirm it with a timing light? if a computer cant understand the what is it makes a terrible job at winging it as far as early computers in cars go
     
  14. Vbb199

    Vbb199 B-rate Hillbilly Customs

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  15. Rusty Nail

    Rusty Nail Re-Re-Elect TRUMP 2024

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    *yawn*
    U didnt fix it yet?
    Too cheap an idea huh?
     
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