[ltbrett]

I recently installed a JB4 on my N55 powered 2013 X5. The power gain is nice and everything appears to be working, except that I am getting strange behavior on the gauges on the mobile app. If I come off throttle on map 1, AFR and ignition timing gyrate wildly. Switching to map 0, all symptoms disappear.
To a trained engineer, which I am, this looks like noise in the circuit introduced by the JB4. I am concerned that spurious signals from my JB4 could cause problems if passed to my ECU. I asked BMS tech support why this is happening and why it is not harmful. Their response was "that's how turbo cars are." I asked for my question to be referred to a higher level of tech support. Crickets.
This reflects either a lack of care about customer concerns, a lack of technical training, or both. Please help, as I would like to keep the JB4 but I'm seriously questioning trusting this product with my engine.

[Steve @ BMS/Fuel-It!]

Okay...to clear a couple things up...
First off the JB4 doesn't pass anything on to the ECU in regards to timing or AFR's.
Second, when you let off the throttle, the engine becomes a huge air pump, so AFR's will go lean and vary because no fuel is being injected. You'll usually see them cap out at 25 and it's normal so you can disregard it.

[ltbrett]

Thanks for the response and for explaining that ignition timing and AFR aren't passed to the ECU. Are they used as inputs to what is passed? What still isn't explained is why there are erratic readings on map 1 but not on map 0. The difference, as far as I understand the maps, is including the JB4 in the circuit, nothing else. I expect AFR to max out when the throttle is lifted, which it does on map 0; I don't expect it to swing erratically. Similar situation with ignition timing, except it keeps swinging around even after I'm back on the throttle. Is it that there is some kind of smoothing on map 0 but not on map 1? Thanks.

Brett

[Martinw2579]

Run a log during a full pull and post the file on here so someone can check it out. JB4 has been flawless for me since i've used them 9 years ago and why I went with them again. They are pretty idiot proof and are helpful on here. They've been at this for a LONG time so have a little bit of faith.

[ltbrett]

Since my questions have gone unanswered, I am returning my JB4 for warranty service. This is so much more difficult than it has to be.

[MrHaloHalo]

The JB4's canbus connection is disabled in map0, so it has no way of knowing (or thus displaying via the mobile app) whats happening with timing or AFR. What's displayed is just the "frozen" values last read before the canbus connection was disabled. So when in map0, the only way to monitor parameters would be to use something like MHD (assuming its already flashed to the DME), Carly, Bimmergeeks Protool, etc.

[ltbrett]

Big thank you to Terry who explained that the logging (and thus display) is different between maps 0 and 1, accounting for the differences I'm seeing. The JB4 is apparently active in map 0 as well, just with a different boost target. Apparently dramatically different traces for each map is normal behavior.