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Discussion Starter · #1 · (Edited)
This started a few months ago. Somewhere in the 45-50% throttle range, 2500-2800 rpm I start getting inconsistent boost/lean spikes and the car falls on its face. Full throttle passes, it runs perfectly and staying outside of that range its fine. Any ideas on where to look for the cause of the boost spikes?
Ive had the same tune for about a year, working on uploading a video but the website wont let me upload the .hpl file I have the data log in.
 

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Discussion Starter · #2 ·
Bad video link, deleted
 

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Get a can of MAF cleaner and spray your MAF on top of clean paper towel for starters.
I would check TB wiring, and look in the log as well.
Also. Could be spark plugs/wires, if they are old.
 

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Discussion Starter · #4 ·

I put it in open loop during this just to experiment.

I'll go clean the maf and check the wiring now. Plugs and wires might have 3k miles on them.
 

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Agree - clean thr MAF. But also check for vacuum leaks or damaged pigtails, etc.

Sent from my SM-G991U1 using Tapatalk
 

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Discussion Starter · #7 ·
The website isnt't giving me an option to upload an .hpl file and i couldn't find a way to change the file format for the data log. Unless I'm just missing the correct attachment option.
 

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I see you are getting mad KR at low throttle %, that ain't good.
No HPT expert by any means, but I would pull out all the plugs and check them for damage, and check the plug gap (also wires, I had wires melting a week after I put them in). If you have access to new MAF put it in and log again. Also, whomever tuned your car originally, I would get comms with them, and have them look at the log.

Edit:
If you can't get a hold of the tuner or what not, post hpt log on HPT forums, that site is more active and there are some knowledgable people on there as well.
 

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Discussion Starter · #9 ·
Working on the car is slow but I went ahead and put new plugs in today(figured if I'm going through the trouble of pulling them might as well get new ones in). Plug wires all looked good. That KR hits in unison with the boost spikes and going lean. Outside of this newer issue car runs entirely without knock. Couldn't find any damage in the wires and I cleaned the MAF.
No change in symptoms after this initial round of digging.
 

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Discussion Starter · #10 ·
Thinking I'll bypass the bypass valve tomorrow, see if I'm having some type of issue with the gate operation causing boost spikes and lean conditions.
 

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Looks like you are leaning out and your STFTs are really high. You dont need new plugs since you are not misfirin. I would check 1. For vacuum leaks then 2. Injectors. What is your timing at full load? I cant remember seeing 23deg at 40% throttle.
 

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Discussion Starter · #12 ·
18 degrees timing at full load, pump gas 4500+ feet elevation.
I disconnected the bypass today and the boost spikes went from occurring every time i drove in that 50% throttle 2500 rpm range to only being able to repeat twice in about 20 attempts. I don't know what to think of that, either it's coincidence or maybe an issue with the spring on the bypass actuator that is allowing it to fluctuate? Without the boost spikes it was getting a little lean but no knock and made it through the area without anything crazy.
 
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