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

**Double0me** · 01-10-2014, 05:20 AM

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!

**Frost** · 01-10-2014, 05:28 PM

That's a bit goofy; you can't be making boost there. What is the part number of the MAP sensor that is in your car right now?

**Double0me** · 01-10-2014, 06:21 PM

from auto zone
Duralast / MAP Sensor
Part Number: SU1477

I have used that MAP for a while now and just in the last few weeks had issues with it. The only thing that has changed as far as parts is the O2 sensor for the WB (Bosch/Oxygen Sensor #15906)

As soon as I let off of the break it will jump forward and idle normally (Rolling idle) with the correct Boost and timing. So far the only thing that comes close to covering it up is setting the absolute spark control to around 14 to 17.

**Frost** · 01-10-2014, 07:55 PM

I don't know what that sensor is, and apparently Autozone doesn't really either. The majority of the vehicles they list it to be specified for have OEM 1-bar sensors. Either way, you don't know the offset value or the absolute linear range for that unit (because it's not published) as it is. The GM part with know values is ACDelco 213-1631 or OE# 12615136.

It's reporting is clearly falsely high. If it's wiring is not damaged, there isn't much else it can be. A would swap the sensor and log.