Engine shutter
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From: Pensacola Florida GO GATORS!!! www.rlsebring.com www.c6c7vette.com
St. Jude Donor '17
Engine shutter
I seem to have a very pronounced engine shutter under wide open thottle. I am doing some fine tuning and before ever making any changes the shutter began.
Under WOT theirs a harsh shutter and noise, not sure if noise is engine, but will eventually smooth out. Looking at the run log in HP Tuners I don't really see anything that gets my attention. There's a little bit of retard briefly and looks to go a little toward lean but nothing major.
I have tried 3 or 4 previous tunes that did good under WOT previously but these also have the shutter. It only does it under WOT. I can speed up very fast but less than WOT and not have the shutter.
Where do I start to try and narrow down what this is?
Thanks in advance.
Under WOT theirs a harsh shutter and noise, not sure if noise is engine, but will eventually smooth out. Looking at the run log in HP Tuners I don't really see anything that gets my attention. There's a little bit of retard briefly and looks to go a little toward lean but nothing major.
I have tried 3 or 4 previous tunes that did good under WOT previously but these also have the shutter. It only does it under WOT. I can speed up very fast but less than WOT and not have the shutter.
Where do I start to try and narrow down what this is?
Thanks in advance.
Pro
Joined: Jan 2010
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From: Apache Junction AZ
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From: Pensacola Florida GO GATORS!!! www.rlsebring.com www.c6c7vette.com
St. Jude Donor '17
I just ran and logged. The only thing I see is at WOT my Commanded fuel drops from 14.68 to 11.38 I don't remember if this is normal or not. Everything else just kinda flatlines.
Safety Car
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From: Mooresville (Race City USA) NC
I seem to have a very pronounced engine shutter under wide open thottle. I am doing some fine tuning and before ever making any changes the shutter began.
Under WOT theirs a harsh shutter and noise, not sure if noise is engine, but will eventually smooth out. Looking at the run log in HP Tuners I don't really see anything that gets my attention. There's a little bit of retard briefly and looks to go a little toward lean but nothing major.
I have tried 3 or 4 previous tunes that did good under WOT previously but these also have the shutter. It only does it under WOT. I can speed up very fast but less than WOT and not have the shutter.
Where do I start to try and narrow down what this is?
Thanks in advance.
Under WOT theirs a harsh shutter and noise, not sure if noise is engine, but will eventually smooth out. Looking at the run log in HP Tuners I don't really see anything that gets my attention. There's a little bit of retard briefly and looks to go a little toward lean but nothing major.
I have tried 3 or 4 previous tunes that did good under WOT previously but these also have the shutter. It only does it under WOT. I can speed up very fast but less than WOT and not have the shutter.
Where do I start to try and narrow down what this is?
Thanks in advance.
Thread Starter
Supporting Vendor
Joined: Sep 2007
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From: Pensacola Florida GO GATORS!!! www.rlsebring.com www.c6c7vette.com
St. Jude Donor '17
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Safety Car
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Normal...car drops into PE (Power Enrichment) mode at WOT. 11.38 AFR is a bit rich for your car but that isn't your problem. Something closer to 12.8 would be better. Under the Engine heading, Fuel tab, power enrichment tab, "EQ Ratio vs RPM" button. Numbers in the cells equate to an AFR value. 14.7 (stoich) divided by the value in the cell is your commanded AFR. "Flatlines" I'm guessing refers to your fuel trims?..normal in PE mode.
Le Mans Master
Joined: Dec 2005
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From: North Western Connecticut
... sounds more mechanical then tune related to me. I'd be looking at coil packs, plugs, wire.... If you've put it back to stock tune and it's actually stock then you can almost bet it's not tune related... Since your not tossing any codes it's hard to say with any certainty... Good luck and keep us posted what you eventually fine... 
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From: Pensacola Florida GO GATORS!!! www.rlsebring.com www.c6c7vette.com
St. Jude Donor '17
I have some known good plugs and wires I'll try tomorrow morning. I'll also add the misfire PID to the scan. Want to see one when ready?
I'm glad I noticed this and hopefully can fix it quick before Talladega next weekend.
Whatcha doin tomorrow?
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From: Pensacola Florida GO GATORS!!! www.rlsebring.com www.c6c7vette.com
St. Jude Donor '17
... sounds more mechanical then tune related to me. I'd be looking at coil packs, plugs, wire.... If you've put it back to stock tune and it's actually stock then you can almost bet it's not tune related... Since your not tossing any codes it's hard to say with any certainty... Good luck and keep us posted what you eventually fine... Yeah I used two stock tunes and a couple of other known tunes. I don't drive hard hardly ever but was on a dark lonely country road the other night and decided to air it out a little.
I was not pleased but I cannot remember the last spirited run so I am not sure when the problem came around. It idles and drives normal otherwise and gas mileage hasn't suffered even on interstate trips at speed.
Safety Car
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Swap those wires and plugs and then log the run. If the shudder is still there email me a copy of the log.
ken
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From: Loveland CO to Central Coast CA
Maybe you got a tank of bad gas... try some octane booster and Techron cleaner?
I believe the C6 retards the timing if detonation is detected. Maybe this causes your shudder.
I believe the C6 retards the timing if detonation is detected. Maybe this causes your shudder.
Last edited by CO Lightfoot; May 22, 2011 at 12:34 PM.
Thread Starter
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From: Pensacola Florida GO GATORS!!! www.rlsebring.com www.c6c7vette.com
St. Jude Donor '17
I run through a tank or two of 93 a week and from different stations so probably not this but thanks for the suggestion. May run some injector cleaner anyway though.
Team Owner
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From: Springfield MO
Hope you get it figured out by Saturday, to run at Talladega. I've been checking the Weather Channel twice a day for the past week and they still keep chance of rain in the forecast for Thursday through Saturday. We have 30 cars drivng down and I would hate to be rained out. If anyone knows anyone at the Weather Channel, could you contact them and have them forecast clear sky's for next weekend.
Thread Starter
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From: Pensacola Florida GO GATORS!!! www.rlsebring.com www.c6c7vette.com
St. Jude Donor '17
Hope you get it figured out by Saturday, to run at Talladega. I've been checking the Weather Channel twice a day for the past week and they still keep chance of rain in the forecast for Thursday through Saturday. We have 30 cars drivng down and I would hate to be rained out. If anyone knows anyone at the Weather Channel, could you contact them and have them forecast clear sky's for next weekend.
Luckily the shutter is only on WOT. I can ramp up the speed fairly fast without the shutter. If all else fails and I break something at least then I'll know what it was.
Try to look us up at Dega. Our car number is 173, Yellow Vert, Black Carbon headlights. I'll have a T on with a big "Jake" on the back. What position at you?
Last edited by RLSebring; May 22, 2011 at 07:47 PM.