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motojunkie motojunkie is offline
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Default Erradic throttle with JB4-throttle spikes - 11-19-2021, 01:44 PM

Hey guys, any help would be appreciated with this. Been dealing with it for a while. JB4 installed, mostly stock car only intake and blow off valve, stock exhaust. Running map 1 on JB4 with BEF on DME, selection 4 is set to 2 for BEF on JB4.

When I do WOT throttle, all seems pretty good. Under half/moderate acceleration there is a certain spot in the throttle where the car gets really jumpy and starts surging. I did a few runs logging and you can see a very visible spike in the throttle metric, it jumps to full while the pedal stays fairly flat. I verified I am on the latest JB4 firmware and same thing.

I will upload a log of 3rd gear full throttle and a 3rd gear half(ish) throttle.

I'm about to the point of just pulling the JB and reflashing to stock.

To note...I've seen similar issues that people have asked about...but I have never come across a solution that has worked for mine. Also it doesn't have this problem when the JB4 is physically removed. Anyone have any ideas?
Attached Files
File Type: csv 211119_1424-3rd-full.csv (12.3 KB, 8 views)
File Type: csv 211119_1423-3rd-half.csv (7.0 KB, 10 views)

Last edited by motojunkie; 11-22-2021 at 07:37 PM.. Reason: forgot to post files
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THE BEAST THE BEAST is offline
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Default 11-20-2021, 08:54 PM

Quote:
Originally Posted by motojunkie
Hey guys, any help would be appreciated with this. Been dealing with it for a while. JB4 installed, mostly stock car only intake and blow off valve, stock exhaust. Running map 1 on JB4 with BEF on DME, selection 4 is set to 2 for BEF on JB4.

When I do WOT throttle, all seems pretty good. Under half/moderate acceleration there is a certain spot in the throttle where the car gets really jumpy and starts surging. I did a few runs logging and you can see a very visible spike in the throttle metric, it jumps to full while the pedal stays fairly flat. I verified I am on the latest JB4 firmware and same thing.

I will upload a log of 3rd gear full throttle and a 3rd gear half(ish) throttle.

I'm about to the point of just pulling the JB and reflashing to stock.

To note...I've seen similar issues that people have asked about...but I have never come across a solution that has worked for mine. Also it doesn't have this problem when the JB4 is physically removed. Anyone have any ideas?

211119_1424-3rd-full
211119_1423-3rd-half
Csv file ?
What are menu 10, 11 and 12 set at ?
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motojunkie motojunkie is offline
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Default 11-20-2021, 09:50 PM

CSV files are attached to the original post. One full throttle and one about half/three-fourths throttle.

menu 10-3000
11-5000
12- 2600
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Steve @ BMS/Fuel-It! Steve @ BMS/Fuel-It! is offline
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Default 11-22-2021, 06:56 PM

You'll need to upload the CSV file to your post for assistance.

Thank you



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motojunkie motojunkie is offline
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Default 11-22-2021, 07:37 PM

My bad, I linked files from another site.....they are attached now to the original post.
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Default 11-23-2021, 12:57 PM

I see what you mean, I guess my next question would be, does it do the same thing on map 0?

If not, then I'd suspect you'll need to adjust menu 12 as it seems when you are partial throttle you're right on the cusp of it being WOT so you oscillate back and forth.



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motojunkie motojunkie is offline
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Default 11-23-2021, 02:08 PM

Quote:
Originally Posted by Steve @ BMS/Fuel-It!
I see what you mean, I guess my next question would be, does it do the same thing on map 0?

If not, then I'd suspect you'll need to adjust menu 12 as it seems when you are partial throttle you're right on the cusp of it being WOT so you oscillate back and forth.
Yes it does it in both maps. Obviously it's more pronounced in map 1 due to higher boost and all, but still there in map 0.
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motojunkie motojunkie is offline
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Default 11-24-2021, 09:43 AM

Any idea what I can do about this? Do you think there is something wrong with the JB4?
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Cannon @ BMS Cannon @ BMS is offline
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Default 11-24-2021, 11:46 AM

Did the issue start when your BOV was installed? If you have a BOV that vents 100% to atmosphere that may be your issue. If it is controlled by throttle (not pedal) input, everytime it drops below 100% throttle it will vent. Maybe go try and record another log but everytime there is a spike pay attention to what rpm it happens at to see if it correlates with the throttle closure.


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motojunkie motojunkie is offline
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Default 11-24-2021, 12:50 PM

Actually it seemed to start when I got new Vargas turbos (factory size) installed. I do have a bov but that was installed well before the new turbos and never had an issue.
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RVA_N55_Fan RVA_N55_Fan is offline
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Default 11-24-2021, 10:37 PM

Could this also happen after installing the BMS bov adapter on n54 or other engine w similar mods? ( like n55)?
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