Anyone with a JB4 style tuning device and have breakup at full boost?

[zyglyrox]

Basically title. I was driving home tonight in mid 60s weather, on a fresh tank of Sheetz 93. Did a 3rd gear pull and it started to break up around 4900-5100rpm and wouldn’t rev any further. Let it settle and tried again with same results. Wondering if I should swap plugs and try again.

I have the panda power tuner with one step colder plugs, only installed maybe 10k miles ago. Wish I had more data to view but anyone have some thoughts?

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[Brian_B]

Did you happen to have an eye on boost pressure?

That's another kinda hidden red line that I hit often in 3rd, sometimes 4th gear. It feels just like the speed governor kicking in when the wastegate flips to drop boost pressure back down, and it can happen at RPMs well under the red line.

 

[zyglyrox]

Did you happen to have an eye on boost pressure?

That's another kinda hidden red line that I hit often in 3rd, sometimes 4th gear. It feels just like the speed governor kicking in when the wastegate flips to drop boost pressure back down, and it can happen at RPMs well under the red line.

Yeah, it hovered around 16-17 PSI first time, second time i got up to 18.4 before I felt it start to break up.

 

[Brian_B]

Yeah, it hovered around 16-17 PSI first time, second time i got up to 18.4 before I felt it start to break up.

Sounds like a very likely culprit right there - hitting the turbo red line on boost and it dumping the wastegate.

 

[burgerking]

You can raise the boost safety limit somewhere in the JB4 settings

 

[Terry@BMS]

Use the JB4's advanced logging feature to do a full throttle datalog and from that you can determine if your problem is with boost, fuel pressure, fuel trims, throttle, etc.

 

[zyglyrox]

well i had a limp mode CEL come on last night while driving. really
bad breakup again, now gonna pull the plugs and maybe throw in some e85 in to up the octane.

 

[burgerking]

Yeah, if it was going over the boost limit it would probably be well before 4900-5100 rpms. Maybe the plug gap got too big or something. I got ruthenium plugs from tune plus. They recommend to change them after 20,000-25,000 miles for best performance. I've probably had them in there a little longer than that.

 

[Original Bender]

Plug gap would be an issue at higher boost levels before 4500rpm I would think.

 

[zyglyrox]

Yeah I’m assuming plugs, these are one step colder from Panda and came “pre-gapped”. Car drives great otherwise and makes boost pretty much without an issue until it hits 18+

 

[Ducati1098]

Yeah I’m assuming plugs, these are one step colder from Panda and came “pre-gapped”. Car drives great otherwise and makes boost pretty much without an issue until it hits 18+

I think the plugs Panda supplies are NGK LTR7IX-11 (6510)

Personally I would pick up some NGK LTR7BHX (95605) which are Ruthenium, not Iridium. They seem to last much longer and have far less issues.

https://www.tunedbyzfgracing.com/product-page/ngk-ltr7bhx-95605-spark-plug-set-of-6

 

[Ducati1098]

Could also simply be a coil issue.
If you haven’t already, you may want to pull codes, see which cylinder is flagging the misfire (assuming it is a misfire)
Then swap coil positions and see if the misfire moves.

 

[MWILD]

It sounds like you're experiencing spark blowout. Do you happen to know the current gap on your spark plugs? Over time, these gaps naturally widen, so it might be worth pulling them for an inspection.

 

[zyglyrox]

It sounds like you're experiencing spark blowout. Do you happen to know the current gap on your spark plugs? Over time, these gaps naturally widen, so it might be worth pulling them for an inspection.

Yep that’s my thought, been waiting for a halfway decent day to dig into it as I don’t have a great place to work on my car. Either coils like Ducati said or plugs is my guess. It drives outside of boost and up to about 12psi before it’ll start breaking up.

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