Hondata

- serial number of your K-Pro
37820-PRB-A06 2068-609057 (37820-PRB-A06 2068-609057)
- KManager version (not 'the latest')
1.4.0.0 Feburary 2010
- what sort of vehicle you have
2003 Acura RSX Typs-S Stock
- what sort of ECU you are using
?K Pro'd Stock?
- a specific description of the problem

So I read all of the information in the manual and searched the site for like a half hour before asking this.

Does launch control (the default rev limited behavior) cut ignition or fuel?

I tried using it and it seems to work in that if I slowly open the throttle it bounces at the configured RPM. However opening the throttle further simply reduces the manifold vacuum and the A/F ratio sky rockets!

Am I correct in assuming that this is not the sort of launch control that you hold wide open throttle with?

Isn't it dangerous to use this if my engine is going to run extremely lean (32:1)?

If this is not dangerous, would I have to disable lean protection?

Is this a result of having a cable connected throttle body instead of a "by wire" type of gas pedal? (I am guessing that "by-wire" throttles like the newer SI's could simply ignor the position of the accellerator pedal and leave the throttle closed to control rev speed...)

Kpro launch control works by cutting fuel - not ignition - which is why you're seeing the AFR skyrocket. It's not injecting any fuel - it's actually a 1:0 AFR but due to sensor limitations and the division by 0 issue, it's just reading 32:1 or so. Same thing if you take your foot off the gas with the car in gear and coast to a stop - there's still a tiny bit of air going through the motor, but no fuel being injected.

I believe lean protection operates on the same principle - fuel cut - pretty sure that's how all the rev limiters/protection/etc work on the Ks.

Killing fuel makes a lot of sense. Cutting ignition would be bad news, as the cylinder fills up with fuel, only to load up the plugs when it tries to turn ignition back on.

There are rev limiters out there (such as the ones built into aftermarket ignition systems for older muscle cars) that cut spark instead of fuel - the only major issue is that, if the exhaust is already hot (car's been running for a while) sometimes the air/fuel mixture will ignite in the exhaust piping. This is a minor problem unless you either have catalytic converter(s) (it'll ruin them) or are running open header(s) that dump underneath the vehicle (you'll catch the vehicle on fire).

It won't flood the cylinders because the exhaust valves are still opening as normal, and the engine speed's high enough that the unburned fuel just dumps out through the exhaust. A bit of fuel will stick to the cylinder walls/plugs/etc, but it'll burn off after the plug starts firing again and the result is that it's richer for a few revs. This might end up resulting a shorter plug life in the long run but hey, they're just plugs.