93 Suburban 2500 ticks under load.

Discussion in 'GM Powertrain' started by jeffrey.falkner, Apr 25, 2011.

  1. jeffrey.falkner

    jeffrey.falkner New Member

    Hello all,

    This only happends when under acceleration, but I hear a ticking sound inside the truck. Its almost like an exhaust tick or maybe like an arcing tick. I am thinking this might have something to do with the lack of power. I have gone through and replaced the cap, rotor, plugs, wires, coil, checked for exhaust leaks, and I can not find anything. Anyone have any pointers?
  2. stephan

    stephan Rockstar 4 Years 5000 Posts

    I gotta go with a small exhaust leak Jeffery. They sound exactly like you describe & are very difficult to find. Have a helper sit in it & power it up under load while you listen. It's most likely near the front, exhaust manifold gasket, header leaking etc. Use about a 2 foot piece of garden hose up to your ear & trace along the manifold gaskets & if you don't find anything there, move along the header pipes.
  3. Ethan

    Ethan Rockstar 100 Posts

    Could it be rod knock? Bent rod, damaged lifter, rockers? Sounds more like a valve problem, cause a header leak would be obvious and wouldn't cause much power loss, but arcing could cause the noise and the power loss.

    Get a spray bottle that sprays really fine mist, and fill it with water, and while the truck is idling, spray it in the engine bay and look for arcing, if it's an arcing problem, you'll see it rather quick.
  4. jeffrey.falkner

    jeffrey.falkner New Member

    If it was a rod knock you should be able to hear it at idle if I am not mistaken. If i am not on the gas you don't hear anything out of the ordinary.
  5. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    Could it be spark knock (detonation)?? I THINK the EGR valves on those truck get plugged up.
  6. jeffrey.falkner

    jeffrey.falkner New Member

    The ticking sound doesn't change in speed or or how loud it is through out the rpm range. I am baffled on this one.
  7. Was thinking the same thing on the detonation theory.....maybe your leaning out to much on hard acceleration.

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