Hi,

I have a C7 z51 with a procharger, headers, and axle back. It's been tuned and hit 580 to the wheel. The problem I'm having is it feels like I hit a rev limiter at about 4K rpm with heavy throttle and it doesn't matter the gear always about at 4K. It sounds and does fine and then all sudden at 4K it cuts like I hit the limiter and then comes back. It's really weird. I read there is an acceleration limiter in these cars? is that true? Any input greatly appreciated because I'm at a loss

 

Is this a A8/M7 car? Also when you say it feels like 4k is rev limiter. Are the RPMs not going over 4k? Have you reviewed your logs?

 

I'm working on logging I'm going to pick up a HP tuner MPVI3 and I picked up a AEM wide band to monitor A/F. I also got a camera mount for the phone so I can get a good video of it.
I was researching and few things I'm looking at.

1) the clutch spring is worn and it's not registering the clutch all way out with the switch and the rev limiter is set to 4000 in neutral. I'm going to adjust the engage switch this weekend to be further in so it registers clutch out much sooner.
2) possibility two, and the scariest to me, the fuel pump is dying and my low side is just dropping off. I bought a low pressure fuel test kit for the car to check this and I'm most likely going to buy the nitro low side hook up and just tap a fuel pressure sensor off it to a gauge in the cabin. I also picked up the AEM gauge to make sure the A/F is staying safe. I really hope it's not this because the pump is a bitch to change.

The weird thing is it won't do it if your in a slightly higher gear and roll into it, like if I go from 3rd and roll into WOT from 3K rpm it won't cut out. It will cut out if I take off from a light and gun it. First is usually ok but then second will cut out at 4K RPM.
I also want to try with TCS and VCS off. It will still do it with TCS off but I know VCS can also cut power if it gets upset. This is kind of scary as I'll have to be careful, I'll do it on a nice hot day with warm tires and just gun it down empty road and see what it does but I don't think this is VCS kicking in.

So first order of business is to get AEM gauge in so can make sure A/F is ok and then I will start with adjusting clutch switch and go from there.

Oh also this is a M7 with a mcleod RXT1200 clutch so no slipping there lol.