Spark knock

Predator support for GM gas vehicles

Moderators: mikel, 06MonteSS

Post Reply
ralphhippie
Posts: 18
Joined: Mon Aug 03, 2020 5:44 pm
Location: Kentucky

Spark knock

Post by ralphhippie »

2007 GMC Sierra 5.3 gas new body style. U7194 with 9r31 I installed the MPG Boost tune and I was getting spark detonation in the lower RPMs. I retarded the timing to -5 still seem to have it so I went back to -7 and it seems worse. I did the data log but of course I have no idea what I am looking at or for. Any help would be appreciated.
Ralph E. Hempen
User avatar
mikel
Posts: 57766
Joined: Tue Jan 16, 2007 1:17 pm
Location: DiabloSport World Headquarters
Contact:

Re: Spark knock

Post by mikel »

Honestly not an issue I have ever heard of with that tune.
Can you try one of the 87 octane or other tunes to see if the issue persists?
Mike Litsch
DiabloSport Brand Manager
Diablo Tech support by phone:
561-908-0040
M-F 8:00 AM to 5:00 PM EST

tech@diablosport.com
ralphhippie
Posts: 18
Joined: Mon Aug 03, 2020 5:44 pm
Location: Kentucky

Re: Spark knock

Post by ralphhippie »

Yes even with the 87 tune I get low RPM detonation. I set the timing on the low rpm setting back to -7 and still have it. Like if I'm on a highway with the cruise set and start pulling up a hill it's sounds awful. Went back to the stock tune and it goes away. Went back to the 87 changed my injector slop. Just drove it 25 miles to work. Cruise set at 65mph long term is at 0.00 and 0.78 still have the detonation when I accelerated. The spark advance shows 32.5. While I'm cruising.
Ralph E. Hempen
ralphhippie
Posts: 18
Joined: Mon Aug 03, 2020 5:44 pm
Location: Kentucky

Re: Spark knock

Post by ralphhippie »

mikel wrote:Honestly not an issue I have ever heard of with that tune.
Can you try one of the 87 octane or other tunes to see if the issue persists?
Yes even with the 87 tune I get low RPM detonation. I set the timing on the low rpm setting back to -7 and still have it. Like if I'm on a highway with the cruise set and start pulling up a hill it's sounds awful. Went back to the stock tune and it goes away. Went back to the 87 changed my injector slop. Just drove it 25 miles to work. Cruise set at 65mph long term is at 0.00 and 0.78 still have the detonation when I accelerated. The spark advance shows 32.5. While I'm cruising.
Ralph E. Hempen
User avatar
mikel
Posts: 57766
Joined: Tue Jan 16, 2007 1:17 pm
Location: DiabloSport World Headquarters
Contact:

Re: Spark knock

Post by mikel »

the timing adjustment in the tuner is only for WOT.
The 87 tune does not add any timing, so if its knocking on the 87 tune my guess is the AFr is lean, i'd try adding some fuel.
Mike Litsch
DiabloSport Brand Manager
Diablo Tech support by phone:
561-908-0040
M-F 8:00 AM to 5:00 PM EST

tech@diablosport.com
ralphhippie
Posts: 18
Joined: Mon Aug 03, 2020 5:44 pm
Location: Kentucky

Re: Spark knock

Post by ralphhippie »

mikel wrote:the timing adjustment in the tuner is only for WOT.
The 87 tune does not add any timing, so if its knocking on the 87 tune my guess is the AFr is lean, i'd try adding some fuel.
Ok. It has 3 different rpm ranges for adjustment to the timing so I just assumed it would be for that range not the wot. I changed the injector slope yesterday evening. -7 . Now at my normal cruising speed the long terms are at 0.0 and 0.78 should I go more negative on the injector slope?
Ralph E. Hempen
User avatar
mikel
Posts: 57766
Joined: Tue Jan 16, 2007 1:17 pm
Location: DiabloSport World Headquarters
Contact:

Re: Spark knock

Post by mikel »

if its still knocking you can try making it a little richer, yes.
Mike Litsch
DiabloSport Brand Manager
Diablo Tech support by phone:
561-908-0040
M-F 8:00 AM to 5:00 PM EST

tech@diablosport.com
ralphhippie
Posts: 18
Joined: Mon Aug 03, 2020 5:44 pm
Location: Kentucky

Re: Spark knock

Post by ralphhippie »

Ok I will give it a try.
Ralph E. Hempen
ralphhippie
Posts: 18
Joined: Mon Aug 03, 2020 5:44 pm
Location: Kentucky

Re: Spark knock

Post by ralphhippie »

Ok so I am at -1.56 on both ltft's. Air temp was at 65° I have my injector slope set at -11. Still getting some detonation. Not as bad but still some. ?
Ralph E. Hempen
User avatar
06MonteSS
Posts: 17964
Joined: Tue Jan 23, 2007 11:33 am
Contact:

Re: Spark knock

Post by 06MonteSS »

at 65* intake air temp, your average LTFT's should be at about +1.5%... Also, you can't just install a tune and then do a new log right away... Every time you install/re-install a tune (or disconnect the battery), all of the learned items like idle, airflow, fueling/fuel trims, emissions readiness tests, etc. all get erased/reset... It takes days/150+ miles to be put on for everything to be relearned by the ECM/TCM and settle back in again before you'd be able to do a new data log and get accurate fuel trim data.
06MonteSS / DiabLew Tune
Image
2014 Camaro SS - 2SS, RS pkg., short-throw shifter, NPP perf. exhaust, BMR strut-tower brace, Cold Air Inductions cold air intake
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com -- www.diablocustomtuning.net
ralphhippie
Posts: 18
Joined: Mon Aug 03, 2020 5:44 pm
Location: Kentucky

Re: Spark knock

Post by ralphhippie »

Ok I was just going by what you had said in a previous post of yours on making adjustments.
LS1/LS2/LS3/LS4/LS7 etc. - LOGGING, ADJUSTING INJECTOR SLOPE
"After you make an injector slope adjustment, you will want to do another log to verify the average LTFT's again. Drive for about 30 miles to let the adjustment settle in and get re-learned by the ECM, then do another log following the info up in the LOGGING: section above." I had been driving it at least 40 mile before taking another data log.
Ralph E. Hempen
User avatar
06MonteSS
Posts: 17964
Joined: Tue Jan 23, 2007 11:33 am
Contact:

Re: Spark knock

Post by 06MonteSS »

yeah, that's ollllllld post/info....
06MonteSS / DiabLew Tune
Image
2014 Camaro SS - 2SS, RS pkg., short-throw shifter, NPP perf. exhaust, BMR strut-tower brace, Cold Air Inductions cold air intake
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com -- www.diablocustomtuning.net
ralphhippie
Posts: 18
Joined: Mon Aug 03, 2020 5:44 pm
Location: Kentucky

Re: Spark knock

Post by ralphhippie »

06MonteSS wrote:at 65* intake air temp, your average LTFT's should be at about +1.5%... Also, you can't just install a tune and then do a new log right away... Every time you install/re-install a tune (or disconnect the battery), all of the learned items like idle, airflow, fueling/fuel trims, emissions readiness tests, etc. all get erased/reset... It takes days/150+ miles to be put on for everything to be relearned by the ECM/TCM and settle back in again before you'd be able to do a new data log and get accurate fuel trim data.
Ok so after 200 miles I did a data log. I have the injector slope set at -9 this is what I got.

Ltft  are +0.78 and +0.78

Intake air was at 64.5°

I did notice a big decrease in the spark detonation but it still has some.
Ralph E. Hempen
ralphhippie
Posts: 18
Joined: Mon Aug 03, 2020 5:44 pm
Location: Kentucky

Re: Spark knock

Post by ralphhippie »

Hello :?:
Ralph E. Hempen
Post Reply