Bad "fake 2bar" question

[mpprotomec]

Anyone have any ideas about what the pcm does with a swapped 2bar map with regards to Baro settings?

How is it handled on a factory 'charged car?

Does it have a limit to its correction?

CAn the system be changed with a feature upgrade from HP?

[Julex]

Why do you ask if the 2bar affects the barometer, it's 2 different sensors? I guess I'm not understanding your questions lol, care to explain?

[mpprotomec]

It is not 2 different sensors.

On a NA GM car with a 1bar MAP, the PCM reads the MAP at key up and sets that value as BARO. Then while its running, it will adjust that value by comparing it to the reading at WOT.

If a 2bar MAP is installed (fake 2bar setup), the initial MAP reading will be about 2.5v. and would be representative of the real baro pressure.

But at WOT, the voltage would be near 5v. at 15psi and the PCM is programmed to reset BARO to the new value. This new value would virtually be 20000ft below sea level and should cause the car to run incredibly rich if it has that much range to adjust the setting.

[Julex]

I've never heard of this being a problem especially since we're running a fake 2 bar on our 2200 cavalier. sorry

[redhotjamedjimi]

id have to agree never had this problem for 2 bar. barometer stuff is all the work of a MAF or Trims which would be fine under low barometer or aftermarket parts.

[imphat0260]

I've never heard of this being a problem especially since we're running a fake 2 bar on our 2200 cavalier. sorry

Did you guys finally get it done????

[Julex]

No we still need an exhaust and dump tube, everything else is there.

[DugsGMs]

Thats a good question. GMs do indeed get the BARO reading from the MAP sensor during KOEO right before start-up. Rather than getting the close to 5v signal it would expect, it would get less. The PCM would think that it was at a much higher altitude than it actually was. Maybe these guys are just tuning around it w/o realizing it and the PCM wont set a MAP DTC using the BARO reading. I never though of that before, good question.

[Julex]

Well in either case it isn't affecting the cars AFR to the point where I've seena difference.