Spark Knock! Help?!
Thread Starter
Teching In
Joined: Feb 2003
Posts: 10
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From: Northern IN
Spark Knock! Help?! HELP! I've read a few TSB's on this, but I'm not sure my symptoms are exactly as described. Symptoms: Any gear (6M) WOT as soon as tack passes 3900 or so, my engine sounds like its snapping stems of wine glasses! Octane boost and fuel system cleaner cure it, but only for about 2 tanks. No SES, no codes. 18k miles on 01'ss. Only mods are G-MAF and K&N. Car came with slp DD. Car is pampered and driven like grandmas buick 90% of the time. What to do? 
Re: Spark Knock! Help?!
Car is pampered and driven like grandmas buick 90% of the time.
I have also heard that certain types of these 'clean air' gases can cause buildup on the piston as well. I drive out of my way to get the gas w/o any ethanol or any other kind of oxygenated fuels...
Thread Starter
Teching In
Joined: Feb 2003
Posts: 10
Likes: 0
From: Northern IN
Re: Spark Knock! Help?! Thanks for the reply hawk, likewise mobe. What i meant by that statement is that the car is not ragged out, I don't overly abuse it. Its usually driven on trips or just arount town cruzin. Most of my fuel purchasing is done at CITGO, occasionally Shell if I'm on the road, and it has never seen anything but premium.
Re: Spark Knock! Help?! A friend of mine said this about gas on www.mfba.org....
I've been filling up at a cheap Citgo by my house with the Tahoe but I'm gonna stop now.
Yup, there is.
Slo, A friend of mine is the regional manager for KTI trucking. You know, those trucks that bring the fuel to all the gas stations. It does all come from the same tank. The difference is, the Amoco's, Mobil's, Shell's, Phillip's, take the stuff from the top of the tank where their is no residue, crud and other stuff. The Citgo's, Speedway's, and other ones that have such "cheaper" gas take it from the bottom.
After it comes out of the main tank, it goes to it's perspective brand and gets all the additive's that each brand boasts about which also adds to the difference.
Believe it or not, this is a common thing. Random misfiring cars come in, the first thing that is asked is "what fuel do you use?" 90% of the time Citgo is the answer. A can of Techron later and all is fine. I've even had it happen to one of mine, a 99 Malibu.
Slo, A friend of mine is the regional manager for KTI trucking. You know, those trucks that bring the fuel to all the gas stations. It does all come from the same tank. The difference is, the Amoco's, Mobil's, Shell's, Phillip's, take the stuff from the top of the tank where their is no residue, crud and other stuff. The Citgo's, Speedway's, and other ones that have such "cheaper" gas take it from the bottom.
After it comes out of the main tank, it goes to it's perspective brand and gets all the additive's that each brand boasts about which also adds to the difference.
Believe it or not, this is a common thing. Random misfiring cars come in, the first thing that is asked is "what fuel do you use?" 90% of the time Citgo is the answer. A can of Techron later and all is fine. I've even had it happen to one of mine, a 99 Malibu.
Thread Starter
Teching In
Joined: Feb 2003
Posts: 10
Likes: 0
From: Northern IN
Re: Spark Knock! Help?! Damn, I read about citgo and it doesnt boast any o2 or any other tree hugger junk so I thought it was ok. Thanks for the wakeup call John. I'll start fillin' from those mentioned and see what happens. If that doesnt work, yank the gmaf and wait till more mods and a dyno tune to put it back.
Geez, I travel all over MI and IN and these states are crawlin with Cgo's. Lesson learned.
Geez, I travel all over MI and IN and these states are crawlin with Cgo's. Lesson learned.
Launching!
Joined: Jun 2003
Posts: 249
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From: texas unfortunately for now
Re: Spark Knock! Help?! same problem with my SS. ported my maf at around 10000 miles and soon after i did that it leaned out my a/f mix and started knocking at around 3800 rpm at wot. ir was really fuking pissing me off. i replaced the stock maf with screen intact and nothing happened. i took it to chevy and the service woman told me that detonation wasnt bad for the engine??? i was like wtf? yeah right. she told me to put in some 44-k to clean out the carbon deposits and do it again a few tanks later and it still hasnt gotten rid of it. im getting it custom tuned with ls1 edit and hope that works.
