Tach bouncing during Decel on M6

exxit · 08-08-2016, 07:05 PM

Anyone else's tach spazz out on them on Decel? Car's engine is completely unphased and it doesn't seem to happen when I'm on it. Usually when i let off and engine brake i'll see it trip out i'd say between 2-4k? I'm close to taking a video and heading to the dealer... but would rather address it myself because I almost always come back from the dealer with dents and scratches.

exxit · 08-08-2016, 07:24 PM

Buddy said it needs a new instrument cluster or has a bad body ground somewhere... Yeesh. I may just live with this until the tach dies. Don't feel like being Car-less for a few days while this is taken care of.

stratt · 08-08-2016, 08:09 PM

Manual Trans? Do you have rev match on?

exxit · 08-08-2016, 08:59 PM

Manual trans, rev match on or off doesn't matter. Tested that today.

Pretty much rev up and decel... during decel it'll spazz back and forth for a quick second and then match up to what I would say is the right RPM. The engine itself is smooth when that happens, no mechanical "spazz" lol sorry I don't have a better word. I can take a video but it's pretty self explanatory.

exxit · 05-15-2017, 03:28 PM

Doesn't seem like too many people are seeing this... but I did get a report from 2 other owners that have.

Anyone else noticed their RPM needle spazz out? Seems to be directly correlated to having a hot day above 80's or so? Not 100% Sure.

Spazzes in the same way... No change in engine noise or actual RPM, but the gauge freaks out and jumps around a bit until you go into the throttle. Then it seems like something smacks it in the head and it starts working fine.

Dealer did what they called a "sweep test" and didn't find anything.

CJHyperSS · 05-15-2017, 04:08 PM

I have this occur during decel sometimes as well. I started to notice it after temps started to warm up here in fla, so there may be something to this over 80 thing.

exxit · 05-16-2017, 03:11 PM

Quote:

Originally Posted by CJHyperSS

I have this occur during decel sometimes as well. I started to notice it after temps started to warm up here in fla, so there may be something to this over 80 thing.

Boom... number 4 including me so far...

The last guy thought it was because we were procharged... But the other dude is just boltons and, like me, has been having it since very early on.

V8SS · 05-17-2017, 11:46 PM

Mine 2017 M6, has been doing this for quite some time.. I've not taken it to the dealer for this as it doesn't seem to affect anything else, but it is slightly annoying.
I'm not sure if the temp outside matters but I'll try to monitor.

i007spectre · 05-18-2017, 10:34 AM

My A8 tach bounces around sometimes when I set cruise to 65. Also it goes into V4 mode for a second then back to V8 over and over again, even on flat or downhill roads.

sal55 · 05-18-2017, 12:06 PM

My 2016 SS manual also does this. Just as you described.

bybcous · 05-18-2017, 03:21 PM

Thought I posted in here but I have same problem

bybcous · 05-18-2017, 03:40 PM

Temporary fix I have heard is to unscrew ground under hood and then rescrew it back in. Talking about the battery ground.

exxit · 05-19-2017, 02:59 PM

Hrm that's an idea... Maybe some paint gets in there with the horrible paint job they do on some of these.

It's definitely some sort of weird electrical issue, and so far the only thing I'm certain of is the fact that it does it more when its warm/hot out than when it's cooler (under 75-80)

I'm also on the "it doesn't bother my driving" page for now, but I'd wonder what else may be shorting or not getting enough voltage because of this? who knows. I would think a brown out of some sort would cause the whole cluster to freak out but this is specifically just the Tach

bybcous · 05-19-2017, 05:16 PM

There is paint on my ground, but the temp fix didn't work. But the contacts are no where near the paint

08-08-2016, 07:05 PM	#1
exxit Drives: 2016 1SS D1SC Methfed Lowered Wrapd Join Date: Apr 2016 Location: CA Posts: 632	Tach bouncing during Decel on M6 Anyone else's tach spazz out on them on Decel? Car's engine is completely unphased and it doesn't seem to happen when I'm on it. Usually when i let off and engine brake i'll see it trip out i'd say between 2-4k? I'm close to taking a video and heading to the dealer... but would rather address it myself because I almost always come back from the dealer with dents and scratches.

05-15-2017, 04:08 PM	#6
CJHyperSS Drives: 2016 Camaro SS Join Date: May 2016 Location: Tampa, Fl Posts: 18	I have this occur during decel sometimes as well. I started to notice it after temps started to warm up here in fla, so there may be something to this over 80 thing. __________________ 2016 Hyper Blue 2SS 6SPD NPP ---Former Rides--- 2008 GT500 - 700hp 2009 Z51 Corvette - Cam & Boltons 2009 Roush Mustang - Supercharged 2004 Z06 - boltons 1993 Cobra - 331 Stroker 1997 T/A WS6 - 383 Stroker

05-18-2017, 10:34 AM	#9
i007spectre Drives: 2016 2SS, 2008 HHR ECTO-2H Join Date: Aug 2009 Location: Springfield, Mo Posts: 1,927 View My Garage	My A8 tach bounces around sometimes when I set cruise to 65. Also it goes into V4 mode for a second then back to V8 over and over again, even on flat or downhill roads. __________________ 2016 Camaro 2SS. Hyper Blue, Ceramic White, Auto, MRC, and NPP. 1100 - 9/25 2000 - 9/28 3000 - 9/30 3100 - 10/27 3300 - 10/28 3400 - 10/29 TPW 11/09 3800 - 11/10 4300 - 11/24 4B00 - 11/25 4200 - 12/5 5000 - 12/7 6000 - 12/11

05-18-2017, 03:21 PM	#11
bybcous Drives: 2016 Hyper Blue 1SS Join Date: Jul 2015 Location: hampton roads Posts: 2,763	Thought I posted in here but I have same problem __________________ 1ss/Auto-Hyper Blue acs carbon flash spoiler, bmr springs, gm clear tails. Texas speed cam, 223/227 .635/.635 116 LSA, Kooks Long Tube Headers with green cats, MSD Atomic Air Force Intake, CAI Cold Air Intake, QTP cutouts. 503 hp Best so far 11.5 at 123 with a 1.83 60ft. BMR lower and upper trailing arms and upper control arms,E85 DELIVERED 12/29/15 http://youtube.com/bybcous " no talking only racing on my youtube"

05-18-2017, 03:40 PM	#12
bybcous Drives: 2016 Hyper Blue 1SS Join Date: Jul 2015 Location: hampton roads Posts: 2,763	Temporary fix I have heard is to unscrew ground under hood and then rescrew it back in. Talking about the battery ground. __________________ 1ss/Auto-Hyper Blue acs carbon flash spoiler, bmr springs, gm clear tails. Texas speed cam, 223/227 .635/.635 116 LSA, Kooks Long Tube Headers with green cats, MSD Atomic Air Force Intake, CAI Cold Air Intake, QTP cutouts. 503 hp Best so far 11.5 at 123 with a 1.83 60ft. BMR lower and upper trailing arms and upper control arms,E85 DELIVERED 12/29/15 http://youtube.com/bybcous " no talking only racing on my youtube"

08-08-2016, 07:24 PM	#2
exxit Drives: 2016 1SS D1SC Methfed Lowered Wrapd Join Date: Apr 2016 Location: CA Posts: 632	Buddy said it needs a new instrument cluster or has a bad body ground somewhere... Yeesh. I may just live with this until the tach dies. Don't feel like being Car-less for a few days while this is taken care of.

08-08-2016, 08:09 PM	#3
stratt Drives: Waiting on my 2016 Camaro 2SS Join Date: Dec 2015 Location: North Carolina Posts: 497	Manual Trans? Do you have rev match on?

08-08-2016, 08:59 PM	#4
exxit Drives: 2016 1SS D1SC Methfed Lowered Wrapd Join Date: Apr 2016 Location: CA Posts: 632	Manual trans, rev match on or off doesn't matter. Tested that today. Pretty much rev up and decel... during decel it'll spazz back and forth for a quick second and then match up to what I would say is the right RPM. The engine itself is smooth when that happens, no mechanical "spazz" lol sorry I don't have a better word. I can take a video but it's pretty self explanatory.

05-15-2017, 03:28 PM	#5
exxit Drives: 2016 1SS D1SC Methfed Lowered Wrapd Join Date: Apr 2016 Location: CA Posts: 632	Doesn't seem like too many people are seeing this... but I did get a report from 2 other owners that have. Anyone else noticed their RPM needle spazz out? Seems to be directly correlated to having a hot day above 80's or so? Not 100% Sure. Spazzes in the same way... No change in engine noise or actual RPM, but the gauge freaks out and jumps around a bit until you go into the throttle. Then it seems like something smacks it in the head and it starts working fine. Dealer did what they called a "sweep test" and didn't find anything.

05-17-2017, 11:46 PM	#8
V8SS Drives: 2017 M6 NFG Join Date: Jul 2016 Location: Los Angeles Posts: 214	Mine 2017 M6, has been doing this for quite some time.. I've not taken it to the dealer for this as it doesn't seem to affect anything else, but it is slightly annoying. I'm not sure if the temp outside matters but I'll try to monitor.

05-18-2017, 12:06 PM	#10
sal55 Drives: 2016 camaro 2SS Join Date: Nov 2016 Location: socal Posts: 18	My 2016 SS manual also does this. Just as you described.

05-19-2017, 02:59 PM	#13
exxit Drives: 2016 1SS D1SC Methfed Lowered Wrapd Join Date: Apr 2016 Location: CA Posts: 632	Hrm that's an idea... Maybe some paint gets in there with the horrible paint job they do on some of these. It's definitely some sort of weird electrical issue, and so far the only thing I'm certain of is the fact that it does it more when its warm/hot out than when it's cooler (under 75-80) I'm also on the "it doesn't bother my driving" page for now, but I'd wonder what else may be shorting or not getting enough voltage because of this? who knows. I would think a brown out of some sort would cause the whole cluster to freak out but this is specifically just the Tach

05-19-2017, 05:16 PM	#14
bybcous Drives: 2016 Hyper Blue 1SS Join Date: Jul 2015 Location: hampton roads Posts: 2,763	There is paint on my ground, but the temp fix didn't work. But the contacts are no where near the paint __________________ 1ss/Auto-Hyper Blue acs carbon flash spoiler, bmr springs, gm clear tails. Texas speed cam, 223/227 .635/.635 116 LSA, Kooks Long Tube Headers with green cats, MSD Atomic Air Force Intake, CAI Cold Air Intake, QTP cutouts. 503 hp Best so far 11.5 at 123 with a 1.83 60ft. BMR lower and upper trailing arms and upper control arms,E85 DELIVERED 12/29/15 http://youtube.com/bybcous " no talking only racing on my youtube"

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