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The tach on my cluster and HUD is bouncing around, never reads accurate, bounces from 2000rpms to 7000rpms constantly. Any suggestions? I do have a code for MAF sensor, could that be the cause? Any help would be greatly appreciated. Tach does read correct on scan tool.
Last edited by DBARTZ; Sep 28, 2017 at 06:55 PM.
Reason: add info
The tach on my cluster and HUD is bouncing around, never reads accurate, bounces from 2000rpms to 7000rpms constantly. Any suggestions? I do have a code for MAF sensor, could that be the cause? Any help would be greatly appreciated. Tach does read correct on scan tool.
Do you have any video? I gotta see this...I've seen them bounce 50 rpm or so, but have yet to see a 5000 rpm bounce. Is the car behaving odd when it does this or would it be undetected unless you're actually looking at the tach?
The tach on my cluster and HUD is bouncing around, never reads accurate, bounces from 2000rpms to 7000rpms constantly. Any suggestions? I do have a code for MAF sensor, could that be the cause? Any help would be greatly appreciated. Tach does read correct on scan tool.
I have the same problem without the MAF code. My 2016 thankfully is still under warranty and is a bucketload of lemons 🍋. Less than 12000 miles has had engine rebuilt, torque tube replaced, HMI replaced and the car is in the shop for the bouncing tach. They replaced the driver instrument cluster today and still having problems but say they might have it fixed with update programming of new cluster. Hope to get my 🍋 back tomorrow. Video attached
I had a similar incident last year on my 2014 that was delivered October 2013. So the original battery was ~5 years old. I replaced it and all was fine.
Erratic behavior gauges points to the battery failing. But I am sure your mechanic has verified the battery is good.
This is valuable information: problem started after battery replacement!
There is a voltage sensing wire attached to the negative battery terminal that is easily broken. This causes multiple issues... Double check the wire is intact.
Also - make sure battery cable clamps are firmly on the battery posts and tight.
Pic showing negative battery terminal. Voltage sense cable is the smaller gray wire:
Thanks for the ideas is warranty work thankful and they seem to have found the fault. Your suggestions were on track about electrical gremlins. They found some loose grounds. There are 5 ground lugs that they checked and found 2 loose
Thanks for the ideas is warranty work thankful and they seem to have found the fault. Your suggestions were on track about electrical gremlins. They found some loose grounds. There are 5 ground lugs that they checked and found 2 loose
Do you have any idea where these were my car started doing the same thing 2015 vette.
I just put a new battery in it. The tach is still going nuts. The old one had a date of 11/14 on it so I was due to replace it. So what should I try next?
A loose ground connection will cause very erratic tach reading. Mine was bouncing from peg to peg. Really look at grounds and connections at battery. Also grounding bolts on frame under hood
I’m bringing this back up. Did anyone ever find a rock solid answer to the bouncing tachometer issue?
My car did this when I got it about a month ago. The battery was brand new and I did in fact find the voltage sensing wire on the negative post was broken. I fixed that and it didn’t fix the tach instantly but the 2nd time I drove the car after that repair, it quit bouncing and was fine ever since …UNTIL…today. All of the sudden it’s doing it again. I haven’t driven it in a week and it was single digit cold during that week. I drove it to the store today and when I came back out, it all the sudden is bouncing again. I checked all of the grounds I could find and checked my repair and I found nothing out of place. I see a lot of people with this problem but not many reporting back their solution.
Mine has not been a problem after I cleaned the 3 grounds on the driver side frame rail in the engine bay and the two grounds in the driver side footwell.
Mine has not been a problem after I cleaned the 3 grounds on the driver side frame rail in the engine bay and the two grounds in the driver side footwell.
I haven’t got to the ones in the footwell yet. Got all of the ones under the car today. I see the tach signal is provided by the cam sensor. I just took a look at it a little bit ago and everything looked fine. I’ll hit those in the engine bay and foot well tomorrow and see if I get lucky. Electrical stuff is just amazing in how they can come and go at will with no rhyme or reason.
Tach bouncing around C7 Stingray
