2014 Z51 manual Corvette

[freakenrage]

UPDATED:

Hi,

I have a 2014 Z51 7-speed manual Corvette. It has an AFE CAI, an AFE throttle body spacer, and a NPP Borla ATAK exhaust. I bought the DiabloSport 9245 - DiabloSport Trinity 2 EX Platinum. I did the PC update and installed the canned AFE CAI and 93-octane tune, with a couple of things changed. Limiter = off, Shift reminder lights (1-4 suggestion) = off. And installed it. I hit the limiter at 134mph, which is weird because I never got that before I installed the tuner and hit 150mph. I hope this thing did not mess anything up. I have had tuners on other things, and I still do, but not this brand.

Here is the fix that worked for me:

The hard ceiling at exactly 134 mph is a software glitch directly caused by the DiabloSport tuner,

When a DiabloSport preloaded tune is applied—and specifically when you try to change or toggle the "Speed Limiter" or "AFM/DOD" settings—the tuner accidentally corrupts a safety table in the GM engine control unit. Instead of deleting the factory top speed limiter, the software overrides the logic and forces a hard fuel cut at exactly 134 mph, flashing a "Speed Limited to 134 MPH" message.


How to Fix the 134 MPH Glitch
1. Unmarry / Restore to Stock First: Plug in the Trinity tuner to your Z51 Corvette and choose the option to Restore Factory Tune (this unmarries the device from your car). Do not skip this step, or you risk bricking your tuner during an update.
2. Update the Tuner on a PC: Take the DiabloSport Trinity inside and connect it via USB to a PC running the official DiabloSport Ignition/Ignite software. Run all pending firmware and database updates. DiabloSport rolled out patches specifically to address GM speed limiter corruption loops. [1]
3. Re-flash the Car: Plug the updated tuner back into your Corvette. Reinstall the tune of your choice. When prompted to modify parameters, leave the "Vehicle Speed Limiter" option set to default or factory choice instead of manually trying to disable it. The Diablo tune naturally raises the speed limits past the vehicle's capability without you needing to change the manual toggle

[06MonteSS]

Get rid of that throttle body spacer! Doesn't do anything for ya.. gains you nothing.. those are an old-school carburetor trick and does nothing for newer fuel injected/direct-injected vehicles... it can also mess up the air flow and make things worse... so get rid of that spacer!

[mikel]

good find.
what actually happens here is the switch we change to disable the limiter actually enables it on Corvettes since they do not have an active speed limiter from the factory, hence nothing to disable

[freakenrage]

Thanks guys! I'm new to the Corvette world, and the spacer made sense based on what I've read. If it is a waste and does nothing, then yes, it's time to let it go.