Spark Knock or normal? With video!

Buckeye920 · October 16, 2016

All right guys, I finally got tired of this, and GM won't help. so I'm turning to you guys...

I get a loud obvious knock/ping when the accerator is tapped. I can make it do this at will. EIther by taking the t/c off, enabling the e-brake then tapping the accelertaor down, or if I'm just crusing at any speed and I tap the accelrator to pass or speed up it will knock loud! In the video you can hear good right at the begining. I was told it's spark knock, that I should run better gas, so after 4 tanks of shell midgrade nothing has changed. Any ideas?

Brianibew · October 17, 2016

Have you tried a different gas station? Maybe that shell station has some crap gas in their tanks? Your correct in your assumption though, that noise isn't a "normal" noise and definitely sounds like a spark knock. How many miles on it? Your valves me be caked up with carbon aggravating the issue. If it were me, I'd do a GDI intake cleaner treatment and then run a couple tanks with a Techron treatment to clean up

the injectors. Keep us posted.

fbachman · October 17, 2016

Try a different brand of gas. I wouldn't put shell in a rented lawnmower.

Did some tuning back in the day, and shell caused engine logs and knock retard to behave like a chimp on crack.

It really sounds like pre-detonation to me. Although, one short video is not a lot of information.

Just for kicks, try exxon/mobil, Texaco, BP or chevron 93 at your next fill up and see what happens.

I know 93 is overkill with a stock calibration, but it will rule out pre-detonation if that's what it is.

Have you tried to pull any codes? The check engine light does not have to be on. This phenomenon could cause an intermittent code which will wipe itself if it is not a consistent occurrence.

Just some suggestions.

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kstruckcountry · October 17, 2016

Try another 89+ octane would be my suggestion. Sounds different, even in my old pickup.

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Buckeye920 · October 18, 2016

Have you tried a different gas station? Maybe that shell station has some crap gas in their tanks? Your correct in your assumption though, that noise isn't a "normal" noise and definitely sounds like a spark knock. How many miles on it? Your valves me be caked up with carbon aggravating the issue. If it were me, I'd do a GDI intake cleaner treatment and then run a couple tanks with a Techron treatment to clean up

the injectors. Keep us posted.

Yes, I've tried higher ocane and gas from BP. I just passed 21,000 miles What is this GDI intake cleaner you speak of?