[Shotimes] BARO sensor

[Adam Parrott]

>> One of the things that I would have expected a datalogger to do is show all
the sensor inputs to the PCM and their values.  Because the BAP can affect A/F
mixture, this would be one of the key sensors. <<

Actually, the TwEECer software is capable of datalogging BARO readings on both
V6 strategies (X2J and D4U1).  I haven't looked at Tim's datalogs closely
enough to notice whether he had datalogged this variable yet.

>> Finally, what are the correct values the BAP should be posting to the PCM
at sea level. <<

In addition to the voltage values that Paul posted for testing the BARO sensor
(excellent info), there are also calibration-specific transfer functions for
the BAP that are unique to each strategy (eg. X2J, D4U1, etc.).  Once I've
found these functions in the two V6 SHO strategies, I will post the numbers
here for everyone to compare with the Helms data.

Adam


  ----- Original Message -----
  From: Carl Prochilo
  To: shotimes@autox.team.net
  Cc: Timothy Tyner
  Sent: Sunday, September 18, 2005 9:18 AM
  Subject: Re: [Shotimes] BARO sensor


  One of the things that I would have expected a datalogger to do is
  show all the sensor inputs to the PCM and their values.  Because the
  BAP can affect A/F mixture, this would be one of the key sensors.

  I remember reading a long time ago that you could tap the BAP sensor
  lead and measure a very small voltage change as you operate the
  throttle as a way of verifying the operation of the sensor.  If you
  have a datalogger this should be much easier.  Can someone that knows
  these values please post them here?

  Finally, what are the correct values the BAP should be posting to the
  PCM at sea level.
  --
  Cheers,
  Carl Prochilo
  92 Ultra Red Crimson

  On Sat, September 17, 2005 12:57, Kevin & Cheryl Airth said:
  > Tim The Tool Man:
  > Great screen name!
  > That's a tough one to troubleshoot. It very well could be the cause of
  > your
  > lean running but then again maybe not? The easiest way is just to swap
  > sensor's. There have been several long term drivability problems that
  > were
  > finally found to be the BP sensor but no code was set. The sensor was
  > still
  > operating in the correct range of values but was not changing at all.
  > This
  > made the car drive OK at some engine speeds and loads and to be WAY
  > off in
  > other conditions. It's mainly used as an altitude compensation device
  > so the
  > closer to sea level you drive the less of an effect a bad BP sensor
  > will
  > have.
  >
  >  Do you have access to another sensor?
  >
  >  The sensor can be checked with a frequencies counter. Yea, I know who
  > has
  > one of these? Anyway at sea level you should be seeing around 160-170
  > Hz. As
  > you apply vacuum to the open port the frequency should decrease to a
  > low of
  > somewhere around 90Hz. The sensor has 3 wires. One is the 5 VDC
  > supply, one
  > is a ground and the middle pin on the sensor should be the changing
  > output.
  > I do have instructions for using a tachometer to read the frequency.
  > Set it
  > on 4 cylinder setting and you should see 4800 rpm with no vacuum and
  > the
  > rpm's should decrease with increasing vacuum.
  > .
  > .
  >
  >
  >
  >> What symptoms will I see (if any) of a bad BARO sensor?