Quick Sh0t xMLx

Hello, I've had this gigantic problem with my car for the last 5 months now and nothing that I've tried has come close to fixing it. When I go to the drag strip the car won't launch for ****. It'll cut fuel(or an incredibly lean spike I don't have a WB) and it consistently pulls a 2.0x 60.' It was pulling 1.5x 60's in February and all of a sudden it just stopped launching with no changes to the vehicle. It does the same exact thing on the motor and on the nitrous.

One observation I've made is that it only does it on my drag wheels. They're a set of 17" wagon wheels with no TPMS with 275/40 MTs. On my 275/40/18 street tires the car doesn't cut any fuel off at all. I was reading that Active Handling will stay enabled even when you turn it off if there is some kind of TPMS error. I don't know if that's true or not but I've exhausted all other options.

Things I've done/checked/observed in an attempt to fix the problem:
-There is no burst knock, knock, or any timing pulled
-Traction control On/Off it doesn't matter it does the same thing every time
-Torque management, abuse, and every traction control parameter that I can access via HPTuners is turned off
-All the air/fuel parameters are stock, it did this before and after the headers
-As mentioned earlier it launches fine on the street tires

I've attached a short log on the street(with the street tires and TCS off), an NA log from the dragstrip and my tune.

Old Geezer

iTrader: (3)

Tpms =??

lt1pwr1

iTrader: (1)

You probably have a bad MAF. Have you tried swapping it to see what happens?

Quick Sh0t xMLx

Oh yea my bad, wrote it on the Corvette Forums where people know what I'm talking about. Tire pressure monitors.


It doesn't throw any codes or anything. I might be able to find one but as far as I can recall everyone I know has the IAT/MAF built in one where I have the older one. Besides swapping one how would I know if it's bad?

Old Geezer

iTrader: (3)

I don't use HPT, so I can't look..Thus the ??'s that may not apply.
NE connection between TPMS and fuel cut?
IE: TPMS sees no input sig, and immediately cuts fuel to help avoid a low tp/possible wreck??
Trans slip test, [if used], showing a problem with slip, due to better traction w/ slicks vs street tires?

2xLS1

iTrader: (25)

In the track log the narrow band O2s show a lean spike at 3300 rpms while the injector pulse widths stay constant. To me that indicates a fuel pressure/fuel volume/fuel delivery issue. I can't explain why unless the launch at the track somehow effects the fuel pick up in the tank. You see it slightly in the street log but not as severe.

RWDCelicadude

Check your battery hold down, I've seen cars have a loose battery and the terminals will arc to something when the battery shifts under a really hard launch.

2xLS1

iTrader: (25)

It's a Vette. They don't have that problem like the F-bodies. The logs don't indicate anything like that happening either.

RWDCelicadude

It's an easy quick check that often gets overlooked, I just thought I'd toss it out there in case something has been modified or is abnormal.
I didn't know F-bodies had that problem, I've got a RX7 but I've seen it on a couple different cars with different setups so you never know.