Idle MAP reading ~4psi but P3Gauge reading -20inHg
 

Looking for some help on this weird discrepancy between ECUTEK logging of MAP reading vs my P3Gauge.

I have a Edelbrock SC with Delicious tuning with D-Box smoothie. If you see my below log during idle the MAP sensor is reading ~4psi instead of vacuum. interesting enough my P3gauge reading ODB2 sees ~ -20inHg which is more in line.

I'm wondering why there's this discrepancy. Is there something in Delicious tuning that offsets the MAP during ECUTEK logging? which one is correct?

https://datazap.me/u/s0007/2k-6k-pulls?log=0&data=7-23

Stock MAP sensor?

The edelbrock SC kit includes a 2 bar Bosch TMAP sensor. Even though both the P3Gauge and ECUTEK is reading from ODB2 I'm wondering if one is relative while the other is absolute. Spoke with P3 and they said even though the gauge is digital, vacuum is always displayed in -inHg while positive is in PSI

-20inHg is roughly -9.8psi. So if that's -9.8psi relative to atmospheric then 14.4-9.8 is roughly 4.9psi absolute. Not sure if this is correct assumption but welcome feedback here.

Turn ignition full on , but engine off, map srnsor or guage should read 14 psi or 1 bar ie atmospheric if absolute or. 0 psi 0 bar if reliative





Also depends if your looking at reliative pressure or absolute


id say your reading reliative on one and absolute on the other

yep looks ok

No discrepancy, engine computers calculate from absolute pressure. Relative pressure means nothing when calculating amount of fuel needed.

Thx got the gauge to stay on with engine off and it reads 0 PSI.