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Not hittin on all 8 cyl. when i give it the gas

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by deek, May 16, 2003.

  1. deek

    deek 1/2 ton status

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    at idle it sounds good but after warming up once I put on the gas it looses fire in the #8 cylinder, I know this cuz i have a leak in my rightside header, & when the spark goes out it gets really quiet & looses power, then after letting off it backfires then starts hitting all 8. where should my timming be set at, right now it running at 10 in advance /forums/images/graemlins/confused.gif Please help

    it's a 73 blazer with the 350 &amp; a quadrajet carb,, but the motor might be out of a mid to late 70's truck <font color="blue"> </font>
     
  2. jimmyjack

    jimmyjack 1/2 ton status

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    Two things to check. 1st would be vacuum, my intake had a leak and after awhile when I'd hit the gas it'd feel like the valves were floating, I had no accelleration, no power until I backed off a little. 2nd, spray the headers on each cylinder with a squirt bottle, the spots with the least steam, or bubbles isn't firing. Check your plugs and wires too.
     
  3. sled_dog

    sled_dog 1 ton status

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    too advanced for one. I was set at 10 or 12 degrees, backed it down to 6 and I could tell the difference. Not really in the seat of my pants but I didn't hear as much misfiring.
     
  4. Hossbaby50

    Hossbaby50 3/4 ton status

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    Factory calls for about 6* BTDC of timing. Some motors like more, some don't.

    Check for manifold leaks, vacuum leaks, etc.
     
  5. deek

    deek 1/2 ton status

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    I got plugs that are gapped (.035)for the 73' 350, but I have a later year HEI, should i gap them some more?
     
  6. slimlynn1

    slimlynn1 1/2 ton status

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    I think HEI likes 0.040-0.045. I'm using 0.045, but I have a Crane HI-6 ignition system, but I would try .040.
     
  7. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    It could be several things. Bad acclerator pump in the carb, Choke still partly on, wrong timing, mis adjusted secondaires in the carb.
    Is it a bog or is it actually missing? If it's a bog it's a carb problem, proabably bad accelerator pump.

    For the record 8 degress is what most 350's with HEI need. Both my 75 and my old 79 were 8. If you have ESC distributor then it's less, I think it's 6. If you have FI it's 4. If you have points it's usualy 6 but can be 8. You need to figure out what system you have before you figure out the timing. HEI and I believe ESC are both .045 gap. points should be 035. EFI is .035.
     
  8. sled_dog

    sled_dog 1 ton status

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    factory timing setting on the 305 with ESC in 84 was 4.
     
  9. deek

    deek 1/2 ton status

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    ok so i found my problem,, I fried the No.8 plug boot, I guess is got a little to hot /forums/images/graemlins/thumb.gif
     
  10. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    ok so i found my problem,, I fried the No.8 plug boot, I guess is got a little to hot /forums/images/graemlins/thumb.gif

    [/ QUOTE ]

    Had #6 fry on mine and didn't find it for the longest. Weird how stuff works out sometimes huh?
     

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