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Spark detonation help still needed

Predator support for GM gas vehicles

Moderators: mikel, 06MonteSS

Post Thu Oct 15, 2020 6:59 am

Posts: 17
Location: Kentucky
Had posted previously and received some help them nothing. So thought I would try again.
2007 GMC Sierra 5.3 gas new body style. U7194 with 9r31 I installed the 87 tune and I was getting spark detonation in the lower RPM.

I am using Shell gas and I cleaned the MAF with MAF cleaner. My ltft was at 10.16 and 10.94. I set my injector slope to -9.

After 350 miles I did a data log this is what I got.

Ltft  are +0.78 and +0.78

Intake air temperature was at 64.5°

I did notice a big decrease in the spark knock but I still have it. If I accelerate just as speeding up another 5mph it knocks.  Any help would be appreciated.
Ralph E. Hempen

Post Thu Oct 15, 2020 5:21 pm

Posts: 17783
Location: CT

A-HAA!!! Make sure you are using GOOD gas, it makes a difference... mobil, exxon, sunoco, amoco, bp, chevron are best brands to use, with mobil and exxon being the best..

NEVER use Shell, walmart/sams club/bj's, mom-n-pop, or no-name brands, as it's crap gas/additives that tends to cause a lot of knock retard and less performance/mpg...
06MonteSS / DiabLew Tune
2014 Camaro SS - 2SS, RS pkg., short-throw shifter, NPP perf. exhaust, BMR strut-tower brace, Cold Air Inductions cold air intake -- -- --

Post Thu Oct 15, 2020 5:32 pm

Posts: 17
Location: Kentucky
We have a Mobil station here I will fill up with it this week.
Ralph E. Hempen

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