okay my friend has a bone stock 97 civic ex. nothing has been touched on the engine for a long time and about 2 weeks ago out of the blue it started making a REAL LOUD pinging noise. it doesnt do it at idle. it does it the loudest at about 1/4 throttle. you can hear him coming a mile away its so loud. real loud in the car. its definetly coming from the engine. but the funny thing is if he is holding the throttle 1/4 down and i pull the #1 plug wire off, the pinging goes completely away. same thing if i unplug the fuel injector for the #1 cylinder.

i have check/performed the following.
-checked ignition and cam timing
-adjusted valves
-checked fuel injectors, all working
-replaced plugs, wires, cap
-checked for exhaust leak, maybe vacuum leak??

i dont know if its bad gas or not because he has already let it get empty and refilled at different gas stations and its still doing it. but its definetely has something to do with the #1 cylinder because it goes away when we pull that plug. the higher the rpms, the faster it will ping.

on a side note though: the car drives excellent, no problems at all besides that really loud pinging. im sooooo stumpped, i have never been this stumped before. i hope HT can pull through, please help me

 

Are you sure it's a ping? As in a higher-pitched ping or ticking noise? Or is it more like a knocking sound?

 

more of a higher pitched sound.

 

i really need some help guys..

 

?

 

Use the good gas, my friend said it was spark knock? or something like that. My old z6 used to do it when i ran cheap gas.