Can anyone tell me where the ECU gets its readings from for the BARO sensor?

 

MAP sensor

 

So does the MAP Sensor have a Baro Sensor in it? Or is the ECU making calculations and estimating the actual Barometric pressure based on given inputs?

 

A MAP sensor IS essentially a barometer. It measures ambient air pressure. It tells the ECU the pressure and it takes it from there.

 

Okay, Thanks Man!

 

Its just struck me wierd that in HP Tuners, the Baro reading reads differently from the Map reading during Key on Engine not running. Thats why I thought maybe the two werent related. I also though I read somewhere the ECU had a Baro sensor inside of it. But even that doesnt make sense either. So....Thank you!

 

Some non-GM ECU's do have them inside. Then you hook up a hose to the intake manifold from the ECU. Holley's new Terminator X has this.

 

Sounds like the formula that converts the datastream data to the KPA reading is wrong for the MAP or the BARO reading. I have not seen a GM vehicle that had a different MAP and BARO reading prior to startup. The PCM reads the BARO when you key on from the MAP sensor. It also reads it anytime the throttle is heavily opened at low rpm.

 

Ya Im going off what a guy showed me after he had a mail order tune put into his ecu. Now it runs funny and has issue. one of the perameter I noticed that was off is the MAP and BARO. Thanks for the help!

 

Yes it reads when you turn the key on and engine not yet running. May also check baro at WOT.

Some Fords wont set the BARO until you go WOT

May try a WOT pass and see if it changes, also may try a new MAP, it may be funky