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Issues with boost


hadvw

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Since this is good a place as any to start (sorry if this ends up as a thread hijack): the other day, my 5EAT didn't want to boost past 10 or 10.5 psi (it's stage 3 - will hit 19-22 psi in 3rd+ on a good day). Power was noticeably down, didn't spool up as fast, and it was repeatably limited to 10-10.5 psi for 10 minutes or so (probably 5-10 tries). Then, all of a sudden, it fixed itself, and it's just fine, back to its usual self the last 2-3 days. I checked the vacuum hoses close to the bpv (and where I tee off my pressure gauge line, which is how I knew!) and everything was solid.

 

No obvious leaking sounds, no CELs or anything. Car was still driveable, just down on power. Have had an oil change since, and they didn't say anything unusual - they usually let me know if the level's low or something.

 

Also going to get valve cover gaskets and power steering line/o-ring done this week to get rid of the stink coming in through the vents when on fresh air.. Anything I should have them check?

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If it happens again, datalog it while the boost is still down. It could be that your DAM dropped below the Boost Control Disable (DAM)(Disable/Re-enable) thresholds in your tune.

 

In my tune, boost control gets disabled if DAM drops below 0.35 and is re-enabled if/when DAM later rises above 0.65. A year or so ago my IPR TMIC was intermittently touching the pitch stop mount and the noise/vibration was causing a bunch of false knock. A couple of times DAM dropped as a result of the noise and triggered the boost control disable. Later during the drive, I got back on the throttle, DAM started to increase and boost control was re-enabled. AFAIK there's no DTC/CEL for this (overboost fuel cut can/will trigger one though).

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If it happens again, datalog it while the boost is still down. It could be that your DAM dropped below the Boost Control Disable (DAM)(Disable/Re-enable) thresholds in your tune.

 

Thanks for giving me a place to start! So far, no more issues. This is really the first boost-related issue I've had in almost 10 years of ownership..

 

She's slated for a full overhaul of hoses (see Free Range Racing kit), Avo intake, Grimmspeed TMIC and CNT catted DP over the next 2 months or so.. and then maybe a hexmods F1.

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