Lack of power in boost / under load
 

Hey guys, I'm trying to diagnose an issue I recently started having with my NB2.

Recently, the car has been feeling a little sluggish and not accelerating under load like it used to. I tried doing a couple pulls and the car would sound like it's hitting the rev limiter for a few seconds before it would finally accelerate forward. I've attached a log of me doing a second gear pull to demonstrate this. I think spark is being cut but I'm not sure why.

The car was tuned over a year ago and I haven't had any problems like this before. No parts have been changed recently.

Parts:
NB2
T28 turbo
flow force 640cc injectors
ms3pro pnp
stock fuel pump
whatever plugs FM included in their no electronics kit

Let me know what other info I can provide to help figure this out.

You've got launch control stepping in. Turn all that off and try again. You can see that the "status 2 and Status 3" fields are changing. This is what tells you what the ms is trying to do.

Thanks! TIL about the status things in the log.

I reloaded my original tune file just to be extra sure nothing fucky was happening and turned off launch control. That seemed to largely fix my issue. One odd thing that happened though was after shifting to third gear and continuing to go WOT the battery light came on temporarily on the dash. Roughly 11.5s and 29.5s in the log. So now I've got something new to look into.

You are triggering wide open throttle mode on your alternator control. This shuts off the alternator when you are WOT. But the lost 2-3hp is nothing when you've got boost. You've got it set to 101%, which is generally off, but you need to re-calibrate your TPS so you don't trigger that WOT alternator shut off.

Awesome, thank you so much! I was just looking up prices on new alternators.