Chevy 350 TBI Timing issues, Please Help!

Discussion in 'Chevy C/K Truck Forum' started by mace1530, Dec 2, 2011.

  1. mace1530

    mace1530 New Member

    Hello All,
    I am new to this club, and look forward to any help You all can provide, Thanks in advance!
    I have a 1990 (chevy of course) 4x4 stepside, 5.7 TBI, that I am restoring. When I bought the truck, the motor needed rebuilt. I took it to a reputable performance shop, and the following done: bored 30 over, 10.5 to 1 pistons, rotating assembly balanced, new crank(gm), com cam(extreme energy, the largest i could go without any modifications to heads or transmission), heads redone(completely new valves, rocker arms, etc..).
    Everything inside the motor is new.
    The truck fired right up, and runs fine, however, when trying to time it(disconnecting esc, etc..) I am having some issues. When the timing is set "where it should be", (0 degrees with esc disconnected, and changing drastically when i reconnect it to the positive, somewhere in what I would assume to be around 18 or so to the positive) the motor dies when i turn the wheel, or put it in gear. With the esc disconnected however, the truck seems to run fine other than a check engine light being on.
    Any thoughts? Thanks!!!
  2. ejohnson03

    ejohnson03 Epic Member 5+ Years 1000 Posts

    Welcome to the site.

    I have pretty much the same setup.

    When you say disconnect the "esc" are you referring to the ECM computer connection?

    Yes, you time the motor with that disconnected.

    I set mine to about 18 degrees positive, kind of go by sound. Might actually be a tad more.

    Anyway, since you went to the trouble to replace all the internals to the motor, did you update or upgrade any of the electrical stuff?

    Should replace at least the cap and rotor in the Distributer. But it is best at this point to go with a new distributer and coil.

    New plugs and wires will also be a plus.

    And one other small thing, install a new fuel filter.

    It is usually the small things that hang us up.

    Anyway, those are my thoughts. Hope that helps.

    Good luck, let us know how it turns out. And post some pics also...
  3. mace1530

    mace1530 New Member

    Thanks for responding!
    esc, electronic spark control(tan wire with black stripe located on the firewall).Did not replace cap and rotor, fuel filter, or distributer, but new plugs and wires. It seems like the motor doesnt have enough vaccuum when i time it properly. when put in gear, i have to feather the gas to keep it running, but if i leave the esc disconnected, i don't have this problem. If I cant diagnose this, can I still drive the truck without causing any damage(with the esc disconnected)?
  4. ezdaar

    ezdaar New Member

    check cam card, Zero base timing probly really retarded for that cam.
  5. mace1530

    mace1530 New Member

    Thanks Ezdaar, but not sure what you mean by the cam card....sorry...
  6. ejohnson03

    ejohnson03 Epic Member 5+ Years 1000 Posts

    Try to advance the base timing to about 6 or 8 degrees.

    Hook up the tan wire back up and give it a run.

    I think that is what I ended up doing.
  7. mace1530

    mace1530 New Member

    Thanks for your response, but I tried that, and no luck. motor still dies when i put in gear, or turn the steering wheel all the way right or left.....if I leave the esc wire disconnected, will it cause any damage? Thanks again!
  8. ejohnson03

    ejohnson03 Epic Member 5+ Years 1000 Posts

    Hate to say it, but sounds like it is time for a new distributer...
  9. Scott_Anderson

    Scott_Anderson Rockstar 100 Posts

    They say that there is no such thing as a stupid question, but.....
    Could it be possible that the ESC is advancing the spark too much for that cam?
    I have not had much experience with "hotter" cams so I not any expert, but if the engine runs well with little to no electronic spark advance.......
  10. ejohnson03

    ejohnson03 Epic Member 5+ Years 1000 Posts

    It was a bit tricky when I set the timing on mine.

    Just had to be sure to advance the timing before pluging the connector back in.

    Come to think of it, I did also have a CHIP programmed for all of my upgrades.

    Don't know if that would make the difference.

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