Auto Repair Help


by Kyle McFadden

The engine “pings” or knocks on acceleration. The symptom is more pronounced when the engine is at operating temperature.

Engine ping is the result of abnormally high combustion temperatures. The usual cause of engine ping is over advanced ignition timing, an inoperative EGR system or improper fuel usage. A defect in the cooling system can also result in engine ping.

First, do not confuse engine ping with a mechanical failure that produces an internal knock in the engine. An engine knock will be a deep sound that eminates from the engines lower section and will be present under almost all operating conditions. Engine ping is usually present during moderate to heavy engine acceleration after the engine has reached or is near operating temperature. The ignition timing should be inspected and adjusted according to manufacturers specifications. Some vehicles use computer controlled ignition timing that is not adjustable. Consult your owners manual for the recommended fuel rating. A vehicle that is designed to operate on high octane fuel should not be operated using lower octane fuel. Switching to a higher octane fuel may be the only corrective action necessary. If the ignition timing and fuel octane rating are correct, a functional check of the EGR valve will be necessary. Inspect the vehicles cooling system operation. If the vehicle is running hotter than normal or overheating, than that symptom should be diagnosed first. Refer to the “Engine Overheats” article for further diagnosis.

Use caution when working around hot or rotating engine parts.

(Kyle has an affinity for Pale Ale and tooling on his 1956 Chevrolet Nomad Station Wagon.)

7 responses to “Diagnose Engine Pings Or Knocks On Acceleration”

  1. william says:

    Hi i wonder if this also is for snowmobile engines

  2. Renate Moeller says:

    I love this article. Thanks for sharing it. I am getting code P0325 and P0330 only when I drive my car (1998 Toyota camry V6). My question is if the ECU looking for a signal from the knock sensors only during driving and not during idle?

  3. Quita says:

    My 2014 Mitsubishi has been pinging for at least two yrs. A year ago I asked the service manager what causes the ping and he blamed it on the gas I was using. I”ve tried better gas for a period of time and it’s still pinging. 50.000 miles. seems to be more of a noise now when I accelerate. Any Suggestions??

    • Donald says:

      Check your EVE Valve, otherwise known as a PCV Valve. A faulty one can cause preignition in your pistons which in turn causes these punting or knocking sounds. I’m assuming this occurs especially during acceleration until you reach a certain speed (anywhere between 20 and 30 MPH)

    • yvonne elam says:

      try a higher octane fuel .does it just ping while accelerating?

  4. Robert Mckay says:

    I have a 1985 GM 3.8 omc inboard I DID A COMPLETE TUNE UP..starts immediately runs smooth on idle..during accelearation it pops when hooked to a garden hose…in the lake it knocks under load..

  5. Karen says:

    I just had an extensive tune up on my 2004 toyota highlander. Now if pings upon acceleration.

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