2Bar SD OL FI LS1 4L60E Goes into boost while at stopsign.....

[doubleome]

This has been kicking my but and I would like a fresh pair of eyes on it if possible. When at a stop sign my boost will raise positive and my timing will drop to 0.0 the idle will drop down to 550RPM. I have tried adjusting timing, VE and Airflow but am not making any progress. Any suggestions? My set up is as follows.


1999 LS1 2Bar SD OL 4L60E 60lb Siemens ngk wideband P1SC 8-10lbs boost.

I just moved from Colorado to Hawaii and am still adjusting my VE table so please don't mind that mess.

Thanks in advance!

[Bill@HPTuners]

supercharger bypass valve issue or similar most likely. You seeing boost at idle is NOT a tuning issue.

[doubleome]

I didn't think so, but I figured I would ask. I am swapping out the Map sensor and will also check for any weird vacuum leaks. At lease I am not loosing my mind.

[danieloneil01]

Check to make sure your bypass valve is open. When you see it go into boost next time jump out and look at it. It could be sticking or you have a leak from the vacuum hose off the valve to the vacuum source.

[doubleome]

That's half of what is making this so hard to track down. As soon a I shift to Park or Neutral it correct its self. Timing jumps back up, Boost drops to vacuum and idle raises back to 900 -1,000 RPMs. It only happens in gear at a complete stop.

[doubleome]

It was the MAP Sensor. Replaced it and everything is back to normal.

[LSxpwrdZ]

I was gonna say if you legitimately are seeing boost at idle it wouldn't be at idle very long as it would rev with airflow like that. Plus a centrifugal blower (especially the baby P1SC) isn't going to have enough RPM to generate boost at idle.

Glad you got it fixed.