[OzzieSS]

I just bought a 2016 SS with an A8 that only has 24K on the odometer. The car looked super sweet from the highway so I stopped and checked it out. Four hours later I bought the car after some serious negotiating on both sides. I specifically told my salesman to NOT put any more gas in the car if they weren't going to use 93 octane. He insisted they did so I took his word over it. But I quickly noticed some spark knock right after I left the dealership and that has me wondering. Did my salesman lie about using 93 octane or worse, does my new baby have an issue with spark knock that I need to worry about? I've been driving as much as I can so I can drain the tank down to almost zero so I can refuel the tank with the same 93 gas I've been using for years and years....

I'm seriously hoping the salesman lied to me about using 93 octane which should explain the spark knock.....

[oldman]

same thing with my new Camaro, dealer filled it with cheap stuff even though I was specific about my free tank full, car ran poorly, I filled 1/2 tank of 93 half way home and it was better. Dealers are MORONS.

[KingLT1]

These engines show spark knock on 93 with the stock tune. The knock sensor thresholds are set very aggressive due to the high compression and being a fail safe in the likely hood that somebody puts low octane fuel in.

[wookwook]

same experience on a new 18 hold over 2turbo. but yours has miles. don't get too freaked out run it down and refill with 93. it should "re-calibrate" over time. you can do a dose of over the counter anti-knock stuff it does work in the short term. you might want to see if the dealer can probe the ecu and see if its ever been flashed. that would be interesting to see what comes of that and what their response is.

[ssmofo]

How do you know you have spark knock?

[KingLT1]

Originally Posted by ssmofo

How do you know you have spark knock?

With software that monitors and logs data from GM parameters inside the ECU.

You can use HPtuners scan software

P3 guage(there are others)

Torque pro app on a smart phone with a obd2 Bluetooth device

Several different options

[95 imp]

Originally Posted by ssmofo

How do you know you have spark knock?

Most scan tools have a live parameter reading.

Plug it in, set up the inputs you want (IAT, water temp, spark knock, etc), floor it and watch to see if you're picking something up.

[grampa_ss]

I think what he's (ssmofo) asking is "how does the OP know he has spark knock?" not how to do it. The OP made it sound like he heard it while driving. He didn't say anything about seeing spark knock in a datalog.

[EV2DEMON]

OP, are you sure what you heard is spark knock, and not the noise from the Direct Injection system?

[TJay74]

if it is true detonation you will hear it, especially when you are driving up against concrete barriers. Otherwise if it is bad enough it can make the check engine light flash. Only other way is to data log the ECM.

[oldman]

It was pinging and it ran poorly under light load highway speeds. I had to use 5th gear to get a little bit more rpm and less load. I live through the energy crisis I know poor quality gas and high compression pinging sounds like.

[KingLT1]

Originally Posted by grampa_ss

I think what he's (ssmofo) asking is "how does the OP know he has spark knock?" not how to do it. The OP made it sound like he heard it while driving. He didn't say anything about seeing spark knock in a datalog.

Yea you are probably right...I was assuming that the OP used a scanner to verify it was knock retard.

[STEVE41]

Dealers always lie and put cheap gas in new cars

[OzzieSS]

Originally Posted by grampa_ss

I think what he's (ssmofo) asking is "how does the OP know he has spark knock?" not how to do it. The OP made it sound like he heard it while driving. He didn't say anything about seeing spark knock in a datalog.

Yes, I can definitely hear the spark knock for which I definitely know what spark knock sounds like. I use to own two '87 Buick Grand Nationals. Hearing any spark knock on those cars back in the day was very, very bad. I'd have to think it's nowhere near as bad on a naturally aspirated engine though.