Tuning JB4 AFR Issue

[VrapterN]

Wondering if anyone here running the JB4 on there VN that has AFR issues?

As of lately on initial start up the app gauges will not monitor AFR's, it stays pinned at 14.6. All other gages are working just fine though. Once the car has warmed up a bit i can shut the car off and start it right back up and they work fine. Data logs show everything in working order too.

At one point it through a code P0130 for low voltage upstream O2 sensor. Replaced that and still same issue. Also replaced the fuel harness for the JB4 and still the same issue. Spoke to BMS, they have never ran into this issue before and said to buy a new circuit board problem solved. Well before i throw 200 dollars at a maybe fix. I would like to see if anyone Has run into this issue before or might know how to help out.

I would greatly appreciate it!

 

[VrapterN]

103 and views and not one comment. That makes me feel really warm and fuzzy on the inside. meaning no one has ever heard of my unicorn for a situation! lol.

 

[tacthecat]

Not an expert but expect the AFR is "thru the roof" rich for the catalytic converter light-off (warm-up) when it's colder outside. How long (days, weeks, months, seasons) have you been using the JB4, what's the local temperature ranges during that time? Is the app part of the JB4 system? has it recently been updated? Bottom line - you're fine.

 

[VrapterN]

Been using the jb4 for about 5-6 months now. No issues until about a month ago. Popped the code. Then the afr's stopped working. Car idles or drives like shit unless I shut the car off and turn it back on. Then she runs like a champ. If I keep doing this which I have been. The engine light doesn't pop on. It's just annoying at this point. At idle afr's are 14.8-15.2. temps here in Wisconsin were in the mid forties in the mornings, mid 60-70 afternoon. This weekend was 70s. Does it no matter what temp. App is recently updated and flashed the new firmware too.

 

[tacthecat]

Suggest relating issue to the fall cooldown. As the JB4 is a "cheater" device it's likely that the Hyundai software can't handle the current weather and the JB4 "false" inputs. If the JB4 has different settings (ie normal -> aggressive) you might try that. Otherwise remove the JB4 and see if the issue clears.

 

[VrapterN]

It definitely has something to do with the JB4. strictly when the the fuel wire itself is tap the into the O2 harness. i can take the wire off the harness, plug my scanner in and the AFR's pop up and work just fine. I dont see any setting for normal or aggressive. ill have to look into that one. Or it looks like ill need to bit the bullet and get a new circuit board and pray for the best...

 

[tacthecat]

Are you saying the car runs fine with the JB4 disconnected? If so and the circuit board is part of the Hyundai then you're likely setting yourself up for failure. Otherwise make sure you;ve installed the JB4 set-up correctly and the wire runs aren't shorting out n anything.