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Who runs FI & a 465?

Discussion in 'The Garage' started by Hossbaby50, Aug 22, 2004.

  1. Hossbaby50

    Hossbaby50 3/4 ton status

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    I am wondering what FI does when you bog it down with a stick tranny. Does the FI try and pop the idle up or does it stall?

    I am running TPI and I may be installing a 465/208 combo soon. I rockcrawl and am wondering and need to know how a FI motor acts when you try and bog it down. Thanks

    Harley
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    I've got a 465.

    Yes, it attempts to keep the engine running.

    Personally I *don't* like that. I'm going to have to edit the PROM some to see if I can get rid of it.

    I don't wheel much, nor hard, but I notice it even on the street. If I try to turn a corner in 2nd gear, and try coasting through the corner (momentum would keep the engine running regardless) the vehicle starts to "buck" and speed the vehicle up. In some situations that could be dangerous, I would rather have the vehicle die, or at least let the vehicles momentum carry it.

    I also noticed on a couple of occassions that letting the vehicle idle in low or 1st, the vehicle would again start to buck. I have a feeling this is attributed to the drivetrain slop in my setup, but it's probably going to be noticeable with any transmission/t-case combo we are likely to run.

    I just got the heads off of my motor, and taking the transmission out of gear, rotating engine by hand, putting it back in gear, then putting the ratchet back on the crank pulley bolt, I get every bit of 90* of crank movement before everything in the drivetrain "snugs up" against the e-brake. (yes, I actually tested that out of curiousity) IMO thats a LOT of slop, but I have nothing to compare it to.

    Anyways, I think the TPI exacerbates any drivetrain slop, which can make for some annoying quirks. I noticed the slop with the carb, but it nver bucked like this, because it really couldn't "artificially" try to keep the engine running at a set RPM, unlike the idle of an injected vehicle.

    It WILL die, say if you are trying to start out on a steep hill in low, and let the clutch out without giving it gas. However, once moving, I have gone up some VERY impressive inclines in 2hi by letting the engine idle. 3.42's and 33's don't make it easy on the rig, but it will climb a good grade at idle no problem.
     
  3. tomseviltwin

    tomseviltwin 1/2 ton status

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    It lugs something nasty. /forums/images/graemlins/crazy.gif
     
  4. TopOff

    TopOff 1/2 ton status

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    Depends on the FI and the programming of the computer. I am not familiar with the stock ones. I suspect anything under 400 rpms (becasue of the fuel injection computer code) would be difficult NOT to see bucking.

    Under 400 RPMs the computer thinks the engine is trying to start and does different things. I have programmed mine to idle at 600, 650, and 700. At 700 it seems to be the best setup for my little 266 cam (409 BBC). 750 RPM is better. The problems start to happen for daily driving idling that low. Sometimes it would stall, and it took a while to program that out of it.
     
  5. big pappa b

    big pappa b 3/4 ton status

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    TopOff, what kind of FI setup or you using on the BB?
     
  6. big pappa b

    big pappa b 3/4 ton status

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    Nevermind, I just saw it in your profile /forums/images/graemlins/waytogo.gif
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    I am wondering what FI does when you bog it down with a stick tranny. Does the FI try and pop the idle up or does it stall?

    I am running TPI and I may be installing a 465/208 combo soon. I rockcrawl and am wondering and need to know how a FI motor acts when you try and bog it down. Thanks

    [/ QUOTE ]

    I actually was crawling in my buddy's '87 K20 that has TPI today.

    I can say from experience the computer definitely fights to keep it running, it's great, I really like it. /forums/images/graemlins/thumb.gif
     
  8. fwdjunky

    fwdjunky 1/2 ton status

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    Not sure if this is relevant, but my stock tbi setup with a 465 drives just like a carb in this respect. I can drag it down to any rpm I want without the computer trying to compensate. I LOVE my tbi setup.
     
  9. u2slow

    u2slow 1/2 ton status

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    No funny stuff here when I had a TBI 350/SM465. It would lug on most starts as it weighed 7700lbs and it was very smooth. The only time I noticed the revs jump a little is if you were lugging it and then pushed the clutch in, THEN I would bfiefly see ~200rpm increase. My guess is its just burning off some of the extra fuel its using to keep running while lugging.
     
  10. 75-K5

    75-K5 3/4 ton status

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    My Cherokee does this too, except it's more dramatic. If I lug it down to about 400 rpm and then hit the clutch, it will shoot up to 2000 for about 2 seconds before slowing back down. /forums/images/graemlins/crazy.gif
     

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