Loss of power at high RPM - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

GAD · 12-21-2019, 07:06 PM

Hey all. This is basically the email I sent to my tuner. But I figured I would see what the experienced members of Camaro5 had to say.

I got on it hard 2 times today and this is what it felt like. The first time 65 mph 3 gear, punched it, RPMs went up up up then hit what felt like a rev limiter. Power stopped coming and just seemed to “bounce”. I was passing a car on a 2 lane road so my focus wasn’t on my tach. But I thought surely I’m not going fast to be at a rev limiter. But I went into 4th and kept going.

Then just now I was coming onto the interstate and a car beside me was getting goosey so I punched it. 4th gear 68-70 MPH, RPMs going up up up then same feeling. This time I looked down and the RPMs was just bouncing around 5000-5500 but wouldn’t go over. Almost like I wasn’t getting enough fuel or something

Any thoughts?.

G8One2 · 12-21-2019, 08:13 PM

Valve float possibly

15RS2NV · 12-21-2019, 08:18 PM

I'm still learning about computer controlled engines, but if it was an old school engine I'd tell ya to check the fuel filter. When you were wanting more, but it topped out at a certain point.

CamaroBarb · 12-21-2019, 08:23 PM

May be valve springs

GAD · 12-21-2019, 08:27 PM

Quote:

Originally Posted by CamaroBarb

May be valve springs

How can I confirm?

GAD · 12-21-2019, 08:28 PM

Quote:

Originally Posted by G8One2

Valve float possibly

How would I confirm?

G8One2 · 12-21-2019, 08:54 PM

You have to check the spring pressures. Heavy springs wear out and periodically need checked and replaced. Just comes with the territory when you use agressive cams and heavy / dual springs. They should be checked once or twice a year.

G8One2 · 12-21-2019, 08:55 PM

If the spring pressures aren't in spec, you'll get valve float

GAD · 12-21-2019, 09:03 PM

Quote:

Originally Posted by G8One2

You have to check the spring pressures. Heavy springs wear out and periodically need checked and replaced. Just comes with the territory when you use agressive cams and heavy / dual springs. They should be checked once or twice a year.

I just had my cam installed in July. Shouldn’t need it this soon. Right?

satxrider · 12-21-2019, 09:03 PM

Might be a fuel pressure issue. Have the tuner take a look at your fuel pressures at higher rpms.

G8One2 · 12-21-2019, 09:16 PM

Quote:

Originally Posted by GAD

I just had my cam installed in July. Shouldn’t need it this soon. Right?

Possibly, you won't know unless they're checked. It's also possible, whoever did the install didn't set the installed height which would make it worse. If this is what's going on, it could take out a lifter and a cam because the springs are not properly controlling the valvetrain. You need to check them before you move on to other possibilities.

GAD · 12-21-2019, 10:17 PM

Quote:

Originally Posted by G8One2

Possibly, you won't know unless they're checked. It's also possible, whoever did the install didn't set the installed height which would make it worse. If this is what's going on, it could take out a lifter and a cam because the springs are not properly controlling the valvetrain. You need to check them before you move on to other possibilities.

I’ll definitely check them. If the installation was done incorrectly, wouldn’t this problem presented itself way sooner?

Black_SS10 · 12-21-2019, 10:45 PM

Quote:

Originally Posted by GAD

I’ll definitely check them. If the installation was done incorrectly, wouldn’t this problem presented itself way sooner?

If it is valve float, which it sounds like. It typically happens at higher/faster engine speeds/RPMs.

silversleeper · 12-21-2019, 10:50 PM

Could be so many things, with the weather getting colder even a mouse nest in your intake box.

12-21-2019, 07:06 PM	#1
GAD Drives: Silver 2014 Camaro 2SS Join Date: Dec 2018 Location: Knoxville Posts: 225	Loss of power at high RPM Hey all. This is basically the email I sent to my tuner. But I figured I would see what the experienced members of Camaro5 had to say. I got on it hard 2 times today and this is what it felt like. The first time 65 mph 3 gear, punched it, RPMs went up up up then hit what felt like a rev limiter. Power stopped coming and just seemed to “bounce”. I was passing a car on a 2 lane road so my focus wasn’t on my tach. But I thought surely I’m not going fast to be at a rev limiter. But I went into 4th and kept going. Then just now I was coming onto the interstate and a car beside me was getting goosey so I punched it. 4th gear 68-70 MPH, RPMs going up up up then same feeling. This time I looked down and the RPMs was just bouncing around 5000-5500 but wouldn’t go over. Almost like I wasn’t getting enough fuel or something Any thoughts?. __________________ 2014 Silver 2SS L99 with Roto-Fab CAI, Kooks LT Headers, Kooks Cat-less 3” exhaust, TS Stage 3.2 VVT CAM, Circle D 3200 Stall, E85 Kit, FIC 850cc injectors and Elite Engineering Catch Can. Dynoed at 478rwhp.

12-21-2019, 08:18 PM	#3
15RS2NV Ponies are for girls Drives: 2015 RS LFX Red Hot A6 Join Date: Sep 2018 Location: Southern AZ Posts: 315 View My Garage	I'm still learning about computer controlled engines, but if it was an old school engine I'd tell ya to check the fuel filter. When you were wanting more, but it topped out at a certain point. __________________ H&R 1.8/1.7” drop, Overkill 80mm + intake ported by AFS, 1" insulator MACE, Accel Super Coils, THR cai, JET MAF sensor, Hurst shifter handle, GPP strut tower brace, CI ice cube tray hood vents (functional) @SemperFiCamaro

12-21-2019, 09:03 PM	#10
satxrider Bad 45th Drives: 2012 45th Anniversay Edition SS Join Date: Apr 2014 Location: San Antonio Posts: 548	Might be a fuel pressure issue. Have the tuner take a look at your fuel pressures at higher rpms. __________________ - Carl 2012 45th Anniversary SS - LS3 Magnuson TVS 2300 Supercharger / Alky Meth Injection / Lingenfelter GT12 Cam / Kooks LT Headers, 3 inch exhaust & QTP electric cut outs / Monster LT1-S Twin Disc Clutch / MGW flat blade short throw shifter / Haltech CAI / VMax Throttle Body / DSS Stage 3 axles/ BMR Trailing Arms, Toe Rods, Suspension Bushing and 1" lowering springs / Taylor 8MM Plug Wires / Tuned by Henderson Performance Technologies / EBC dimpled and sloted rotors / G2 Painted Calipers / GM Tower Strut Brace / ZL1 Factory Rep Wheels

12-21-2019, 08:13 PM	#2
G8One2 Drives: 2014 Camaro 2SS Join Date: Feb 2015 Location: Metro Detroit Posts: 492	Valve float possibly

12-21-2019, 08:23 PM	#4
CamaroBarb Banned Drives: cheby Camaro Join Date: Aug 2019 Location: usa Posts: 575	May be valve springs

12-21-2019, 08:54 PM	#7
G8One2 Drives: 2014 Camaro 2SS Join Date: Feb 2015 Location: Metro Detroit Posts: 492	You have to check the spring pressures. Heavy springs wear out and periodically need checked and replaced. Just comes with the territory when you use agressive cams and heavy / dual springs. They should be checked once or twice a year.

12-21-2019, 08:55 PM	#8
G8One2 Drives: 2014 Camaro 2SS Join Date: Feb 2015 Location: Metro Detroit Posts: 492	If the spring pressures aren't in spec, you'll get valve float

12-21-2019, 10:50 PM	#14
silversleeper Big Crow Drives: '13 ZL1 Join Date: Mar 2017 Location: California Posts: 1,493	Could be so many things, with the weather getting colder even a mouse nest in your intake box.