07-08-2023, 01:16 PM | #1 |
Drives: 2019 Chevrolet Camaro RS Join Date: Jul 2023
Location: North Carolina
Posts: 2
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RPM Needle Bouncing
My RPM needle will bounce as I drive... it idles smooth and with no bounce. Any suggestions and or tips would be extremely appreciated as I have taken it to the dealership I bought it from and have a warranty through and they've told me its fine... I'm not convinced. This link goes to a YouTube video I uploaded showing my concern. https://youtube.com/shorts/dYaV9H7gj0s?feature=share
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07-08-2023, 01:36 PM | #2 | |
Drives: 6th Gen LT1 Join Date: Jun 2023
Location: Southeast
Posts: 245
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Quote:
That signal comes from the ECU. It a could be real RPM fluctiations or an issue with the tachometer. I'd say you need to plug an OBD2 diagnose tool and check what the RPM looks like. If they are also fluctuating in the scanner, then you have an issue either with the engine or if it is auto also the transmission. Good Luck. |
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07-08-2023, 01:50 PM | #3 |
Drives: 2019 Chevrolet Camaro RS Join Date: Jul 2023
Location: North Carolina
Posts: 2
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The engine doesn't misfire or act weird, it just pulses while I drive and I can also audibly hear the car sometimes match the RPM fluctuation. Its a 2019 so not to old lol. Maybe I will try switching the crankshaft position sensor out.
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07-08-2023, 02:11 PM | #4 |
Drives: 2018 ss Join Date: May 2018
Location: Tampa
Posts: 185
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Before changing anything i would check it with the obdii
Like previously mentioned. Mine had a wild tach and the Dealer put it on a techii and reprogrammed something to fix it. |
07-08-2023, 04:14 PM | #5 |
Drives: 6th Gen LT1 Join Date: Jun 2023
Location: Southeast
Posts: 245
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If you feel the car matching the tach fluctiation then you have an issue. Might be transmission if auto. Torque converter locking/unlocking or oil pressure in the clutches can cause that.
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07-09-2023, 07:43 AM | #6 |
Drives: 2017 2SS, 50th pkg, M6, MRC, NPP Join Date: Jan 2016
Location: Ocean City, NJ
Posts: 3,182
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07-09-2023, 07:57 AM | #7 |
Thank you Al Oppenheiser!
Drives: Red Hot A10 ZL1 Convertible Join Date: Jun 2017
Location: Sarasota, FL
Posts: 4,978
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Loose grounds cause this. Check 'em.
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07-12-2023, 07:48 AM | #8 |
Hot Camaro
Drives: '20 2SS Convertible 6MT Join Date: May 2020
Location: CT
Posts: 3,534
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If it's an automatic, how many miles on the transmission / current fluid?
It's anecdotal, but I'll relay why I'm asking... My wife's Acura was purchased CPO with about 25k on it. The service interval for a fluid change will vary based on conditions to somewhere between 30k and 60k. Her car indicated the fluid should be changed around 35k or so and we ignored it. Her Accord had over 200k on it and the transmission fluid was seldom changed... At close to 50k we finally got it changed because I noticed the same type of symptoms you're describing... on the highway, with a very slight uphill grade (this ensured you were pressing the accelerator slightly but not hard enough to cause it to downshift), the tach needle would pulse and you could make out a slight change in the sounds from the engine (indicating that it was surging slightly). End result was that the transmission was starting to slip slightly. Acura's change process is to drain and fill the transmission three full times (using approximately 12 quarts of ATF). I had my mechanic do a drain and fill, we drove it for about 200 miles, then returned for a second drain and fill. Car now has about 75k on it and it has been flawless since we took care of it. TL;DR - if you have an automatic and are at/above the 50k mark, consider getting the fluid changed. If your mileage is below that, consider taking your car to a reputable transmission shop for deeper diagnosis. |
07-12-2023, 07:55 AM | #9 |
Drives: 2018 ss Join Date: May 2018
Location: Tampa
Posts: 185
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You guys keep mentioning the transmission. How is a tachometer related to the transmission. If I put the car in neutral and rev the engine, the tach reads the engine rpm's, the trans is not moving.
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07-12-2023, 07:56 AM | #10 |
Hot Camaro
Drives: '20 2SS Convertible 6MT Join Date: May 2020
Location: CT
Posts: 3,534
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07-12-2023, 09:07 AM | #11 |
Drives: 2016 Camaro 2SS Join Date: Jan 2015
Location: Charlotte
Posts: 309
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Most likely a grounding issue. Myself and many others had the bouncing tach on hot days, along with the hot start issue. I followed SSDan's guidance a couple years ago at this link https://www.camaro6.com/forums/showthread.php?t=586153 and it fixed both my issues at once. Haven't had a bouncy tach since.
No reason not to give it a shot. Its quick, easy, cheap and even if it doesn't help the tach, it won't hurt anything. |
07-12-2023, 09:22 AM | #12 | |
Hot Camaro
Drives: '20 2SS Convertible 6MT Join Date: May 2020
Location: CT
Posts: 3,534
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Quote:
Like you said... easy to at least look into if not potentially modify. |
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07-12-2023, 09:53 AM | #13 |
Drives: 2016 Camaro SS Join Date: Oct 2021
Location: Michigan
Posts: 271
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Grounding issue.
Run a nice fat ground wire from the grounding point by the front pass side fuse box to the engine block. This is super easy and cheap, great first step in tracking down the issue.
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07-12-2023, 10:13 PM | #14 |
Drives: 1SS 1LE Join Date: Jul 2018
Location: Farmington Hills
Posts: 100
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Mine.
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rpm, rpm needle bouncing |
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