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1993 1500 engine help

Discussion in 'Chevy Truck Talk & GM News' started by Trueblue93, Nov 20, 2013.

  1. Trueblue93

    Trueblue93 New Member

    1993 1500 5.7 tbi 5speed 4wd .Experiencing a nice knock/tap under acceleration , replaced the oil pump thinking i wasent getting oil to the top of the motor under a load but turns out that wasent the problem. Truck start idles and runs great but when i run the gears out on a merge on the expressway i get a knock/tap out of the motor for a short while but clears it self up if i jus let it idle for a short while .. I also noticed shutting the truck down and restarting takes a much longer time when experiencing this problem .. I replaced the pluggs but not the wires or cap was td they were new when i purchased the truck.. I i also noticed the oil pressure dips down at idle until i bring the rpm back up a bit .. The problem clears up and if i baby shift the gears i dont have a problem . Im going to check the timing and possible adjust the lifters if necessary.. The truck has 300k + on it but motor seems to be rebuilt at milage unknown . Trying not to pull the motor due tonthe fact this is my daily and thats going to set me back .. Im a weekend warrior on the truck finishing up the projects on sundays to be ready to work on monday im hoping it a sensor or some kinda vale that can jus be replaced learning upon reading forums upon forms about spark knock and or knock sensors .. And help will be greatly appreciated
  2. poncho62

    poncho62 Member 100 Posts

    You have to determine if its a knock or a tick.....A knock comes from the bottom of the engine, usually a rod or a main bearing. A tick is from the valve train, lifters, rockers etc.

    Rod knock is a deeper hollow sound...

    I would adjust your rockers to see if that makes it go away. While adjusting them, you will hear what the tick sounds like when you loosen a rocker
  3. Trueblue93

    Trueblue93 New Member

    Im pretty sure its not a rod knock .. Its alot higher pitched .. Jus strange that the truck runs great for awhile but as soon as i go to mash on the gas a bit theres the tap .. It almost never happens on around town driving ..
  4. poncho62

    poncho62 Member 100 Posts

    Is it like a rattly sound when you step on the gas?
    Sounds like detonation or pinging as it is called. Caused by too far advanced timing or poor quality fuel. Put in some high test gas and see if it goes away, that will tell you.

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