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It's great not to suck!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Grim-Reaper, Sep 19, 2003.

  1. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    It\'s great not to suck!

    Well old burb was idling high. I was iddling about 900-950 in gear and 1100 out and in the last week it started idling 1000-1050 in gear1400 out. Obvious vacuum leak. It was the gasket from the intake to the TBI heater (454 thing most of you 350 guys don't have the same set up I understand). My MPG had gone down a little as well, actully a lot...finnaly cooled down here and hardly have run the AC the last tank. Lost 1/2mpg over what I was seeing with A/C on.

    Got the parts and time to fix it last night. BIG improvement! 750 in gear and 1000 out. It also fixed a serge that I was not sure was a serge. I have a warped rim so I was blaming that for a lot of what I was feeling.

    Now I'm curious to see what happens to the MPG. My 454 has a dual plane intake. Only half the engine was getting the leak. This means half the engine was running lean. The O2 Sensor would have seen this and richend up the mix so MPG when in the toilet. Proably throwing off the signal to the MAP sensor as well.

    This has apparently been a problem the whole time I have owned the truck. I'm hoping this will gain a full MPG. Might do even better then that.

    Improvments I see:
    Cold start up is not as high of RPM.
    Faster to come out of high idle.
    Smoothed out the idle.
    Lower transmission temp when in traffic. I had a high enough idle it was starting to really push so It was heating it up. I was seeing 200F on the tranny temp gage if I got caught in traffic.

    Feels like more braking power since the truck is not still trying to push when I stop.
    Cruise control seemed to hold speed better.
    Truck use to bogged a little when cold. Didn't notice it today.

    I also did a "performance" mod and see how that goes. On the R/V20 454 they have a heater the TBI sits on. It helps with cold start and it also helps with preventing freeze up in cold weather. Any hot rodder knows "the colder the intake charger the more dense the fuel load, the bigger the bang." Well the hose was original to the truck and was long overdue to be replaced. I bypassed the whole set up to avoid paying the $70 the dealer wants for a replacement hose. See how it does when the temps drop this winter if that will stay like that.

    Unfortunaly I have done several repairs at once. I have been trying to be systematic repairs and mods to see what each one nets me in MPG. Since I had other problems that were also effect MPG I won't be able to see what gains I get. The truck is stronger feeling but again I contribute most of that to the other repairs. /forums/images/graemlins/thinking.gif
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: It\'s great not to suck!

    Every time I fnid a "major" problem, such as bad plug, wire or messed up advance mechanism, and expect some miraculous increases in mileage, it never happens.

    Don't know why, you'd think way messed up timing in all situations would really affect MPG either in the city or freeway, but it didn't.

    Wish you the best though, nothing like picking up "free" MPG.
     
  3. SUBFAN

    SUBFAN 1/2 ton status

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    Re: It\'s great not to suck!

    Losing mileage with a BB has got to suck. Hope this fixes your problem.... /forums/images/graemlins/burb.gif
     
  4. R72K5

    R72K5 Banned

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    Re: It\'s great not to suck!

    "gas milage" and 'big block" are four words that dont go together very well, but we all already know that much, hehehe

    good luck!
     
  5. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: It\'s great not to suck!

    [ QUOTE ]
    "gas milage" and 'big block" are four words that dont go together very well, but we all already know that much, hehehe

    good luck!


    [/ QUOTE ]


    Hahaha Tha't true. I'm hoping for 10.5-11. This is my DD and I put 45 miles a day on it. Funny thing is it got 9.25 with 7,500 on a trailer. It just don't care how much weight it has.

    Looking at a 95 Rodeo with a motor problem (hopefull just a head gasket) tomorrow for $500. If I buy that for her once it's going I'll start driving her honda. I figure it will pay for it's self in MPG and keep the miles donw on the family hauler/Land tug for the Land Yacht . Hell this burb has 76 K on it and looks like it's 3 years old. It's a 88.
     
  6. monte0172

    monte0172 1/2 ton status

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    Re: It\'s great not to suck!

    My 79 with a 400SB gets right at 9mpg also. I dont care if you are pulling a 19ft trailer loaded to the gills with the a/c on or just driving around town it still get 9mpg. Oh well didnt buy it for gas mileage.
     

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