98 chev tahoe (pinging poblem)

[scott2]

i have a 98 tahoe 5.7 4x4
i have engine pinging. It doesn't do it all the time
i use high test fuel helps a little but it still does it
had the injectors cleaned at GM, put carb cleaner in the intake
changed the EGR. new fuel pump
not sure why it does it some days other not
no codes showing or check engine light
GM says its not pinging enough to set off the knock sensor
could it be a intake gasket or head?
any help would be great
thanks
scott

[Fanuc5]

A spark knock (or pining) is caused when the fuel going in to the cylinder is pre ignited. The cylinder isn’t all the way up in it’s compression stroke, when the explosion happens it tries to force the cylinder down but it cant go down until it has reached top dead center. This causes the ping.

What causes this? A hot cylinder chamber.

What can prevent this? Proper cooling of the engine.


I would check you cooling system and maybe have your radiator flushed, and change out you thermostat to a lower temp.

A higher Octane fuel lowers the temperature at which the fuel will auto ignite.


I hope this helps…

[GMMerlin]

Sometimes carbon buildup on top of the pistons can cause a spark knock problem on those engines..
GM has a product called Top Engine Cleaner that will soften and remove the carbon..
Read the directions on the can!
I have used this product many times..works well