[Maxwagen]

So I put my jb+ on my '17 330ix a couple weeks ago, and everything seems to be ok with it, except for this one issue. When taking off right away with light to moderate throttle from a cold start (i.e. before the engine warmup cycle completes), occasionally the car will "buck", almost as if there is a bad misfire, or a fuel cutoff. This morning it happened, but felt more like a power hesitation than a sudden lurch. This has only happened since putting the JB+ on, which is currently at max setting. I will try turning down to the original 3-o-clock setting and see if this helps.

On a second note, does anyone else notice that the power delivery with the jb+ sometimes feels weird? Almost like an initial surge, a slight hesitation, and then another smaller surge? Kinda like the wastegate can't make up it's mind...

Anyone else experience either of these issues?

[BunkerJ]

Originally Posted by Maxwagen

So I put my jb+ on my '17 330ix a couple weeks ago, and everything seems to be ok with it, except for this one issue. When taking off right away with light to moderate throttle from a cold start (i.e. before the engine warmup cycle completes), occasionally the car will "buck", almost as if there is a bad misfire, or a fuel cutoff. This morning it happened, but felt more like a power hesitation than a sudden lurch. This has only happened since putting the JB+ on, which is currently at max setting. I will try turning down to the original 3-o-clock setting and see if this helps.

On a second note, does anyone else notice that the power delivery with the jb+ sometimes feels weird? Almost like an initial surge, a slight hesitation, and then another smaller surge? Kinda like the wastegate can't make up it's mind...

Anyone else experience either of these issues?

I haven't used JB+, but that buck is normal for BMW's. For some reason, you will get a buck from 1st to 2nd gear with low throttle. Secondly, if you haven't warmed up the car and try to use the throttle, it's really touchy and jumpy. I'd recommend always warming your car anyhow and allow the oil to warm up some.

How much more boost does JB+ provide? I know that on the Dinan Sport+ in the +4Psi mode could have some hesitation when on 91 OCT instead of 93 OCT. I would assume the same for JB+.

[Maxwagen]

This is definetly not the 1-2 shift quirk. This feels like a fuel or timing thing.

In any case, the jb+ is supposed to provide up to ~4psi. Once the warranty is up, I'll definetly consider upgrading to the JB4 for the tunability, as the way the power comes on with the jb+ (at least at my current setting) is a bit odd. But for $199, it can't be beat for sure.

[BunkerJ]

Originally Posted by Maxwagen

This is definetly not the 1-2 shift quirk. This feels like a fuel or timing thing.

In any case, the jb+ is supposed to provide up to ~4psi. Once the warranty is up, I'll definetly consider upgrading to the JB4 for the tunability, as the way the power comes on with the jb+ (at least at my current setting) is a bit odd. But for $199, it can't be beat for sure.

I would let it warm up. I have a custom tune through BM3 and if my car isn't warmed up, it's a bit jerky like yours.

[Maxwagen]

Is there a known reason for this? I'd love to know what's going on behind the scenes of the ECU. Nothing that will throw a shadow code I'm hoping?

[BunkerJ]

Originally Posted by Maxwagen

Is there a known reason for this? I'd love to know what's going on behind the scenes of the ECU. Nothing that will throw a shadow code I'm hoping?

Doubtful on any codes. Been running like this for awhile. Not sure of what the exact issue is aside from it subsiding if I warm up the car for a minute. Lubrication maybe?

[Sweeney921]

Does yours happen in a specific RPM range? My B48 will hesitate very briefly at constant throttle input between 1500-2000 RPM. Like you said, it feels like an air/fuel thing. Pulled all of my codes and did not find anything, Though. Typically occurs on cold days, even if the engine is fully warmed up.

I don't have JB+, my B48 is stock.

[Maxwagen]

No, i haven't had any issues before JB+. And it's only if I get going immediately after starting the car. After about 10 seconds or so, the probably won't show.

[sevalley]

Recently installed a JB+ on my stock 430i GC. The first day I noticed no difference and debated returning it. The second day I noticed a slight increase but thought maybe it's just in my head. The third day there was a significant difference when pulling from the line and accelerating at low RPMs. It's great. My gas mileage has taken a hit since I try to WOT every chance I get now. Best $200 mod ever. Apparently just have to give the engine/computer time to adjust before it really opens up. Definitely installing an intake next.

[MONSTAR]

Originally Posted by sevalley

Definitely installing an intake next.

An intake wont do anything but make a lot of wooshing noises