You have a new PM! Click here here to read it!

Go Back   Ford Diesel Power Forums > Technical Section > 7.3L Powerstroke Technical Discussion

7.3L Powerstroke Technical Discussion Technical info, repair and non performance related discussion for the 7.3L Power Stroke engine here.

Reply
 
Thread Tools Display Modes
  #1  
Old 11-21-2012, 10:13 AM
eaglehawk's Avatar
eaglehawk eaglehawk is offline
stroker envy
 
Join Date: May 2012
Location: Spokane, WA
Posts: 549
Default Barometric pressure sensor

Looking for more info about the Barometric pressure sensor. My truck has a stand alone sensor but it has a computer out of a 2000 SD that we believe has an internal sensor. The current reading on the sensor is -4.57 and remains the same when the external sensor is unplugged. The reading was taken in Athens, TX at about 450 to 550 feet above sea level.

Trying to find out if the reading is false. Also need to know if the Computer a DAC3 has a sensor in it and if so how do I disconnect the stand a lone sensor and short it so that the internal one is working properly.
__________________
Black E'99 F-350 CC DRW, 6637 filter, 4 inch straight piped. Soon to get an 99.5-03 model GTP 38r and intake, 160cc single shot injectors, T-500, regulated return, bellowed up-pipes, banks brake, frame mount 3rd battery 19.5" rims and tires with a little luck a rebuilt motor and trans, led everything. really thinking a ground up on it for a working show truck

"Safety Through Visibility"
Reply With Quote
  #2  
Old 11-21-2012, 12:08 PM
Andrew's Avatar
Andrew Andrew is offline
Moderator
 
Join Date: Nov 2009
Location: Kent, Wa
Posts: 12,490
Default

The pcm makes a calculation based off of the map and ebp sensors I do not believe the pcm on the diesels have a baro sensor what are you scaning with ?
__________________
01 F250 8" procomp, Dynatrac Free Spin, 40's on 20s, garrett gtp38r, intake, 6.0 IC, 4" duals by ats, Sure Flow 325/200 By Farmers Diesel,Tunes by Me , propane (home made) Terminator Groupie.
Reply With Quote
  #3  
Old 11-21-2012, 12:17 PM
eaglehawk's Avatar
eaglehawk eaglehawk is offline
stroker envy
 
Join Date: May 2012
Location: Spokane, WA
Posts: 549
Default

Farmer's computer
__________________
Black E'99 F-350 CC DRW, 6637 filter, 4 inch straight piped. Soon to get an 99.5-03 model GTP 38r and intake, 160cc single shot injectors, T-500, regulated return, bellowed up-pipes, banks brake, frame mount 3rd battery 19.5" rims and tires with a little luck a rebuilt motor and trans, led everything. really thinking a ground up on it for a working show truck

"Safety Through Visibility"
Reply With Quote
  #4  
Old 11-21-2012, 02:55 PM
Justin@DP-Tuner's Avatar
Justin@DP-Tuner Justin@DP-Tuner is offline
Sponsor
 
Join Date: Oct 2012
Location: Oakdale, CA
Posts: 211
Default

Here is some info for you.

Barometric Pressure Sensor
The Barometric Pressure (BARO) sensor is a variable capacitor sensor that processes a signal indicating atmospheric pressure. This allows the PCM to compensate for altitude. The PCM uses this information to calculate injection timing and glow plug control. With the 1999-1/2 model, the BARO sensor is no longer a stand alone component. It is now contained in the PCM.

A BARO sensor fault will result in an out-of-range signal to the PCM. The PCM will assume a default value of 100 kPa (14.5 psi) .
__________________
DP-Tuner
For Your Tuning Needs
www.dp-tuner.com
Like us on Facebook!
828-221-0076 ext.804
justin@dp-tuner.com
Reply With Quote
  #5  
Old 11-21-2012, 03:23 PM
Doug's Avatar
Doug Doug is offline
Old School - New Heart
 
Join Date: Dec 2011
Location: Montana
Posts: 5,055
Default

The OBSs and SDs 7.3s have it, but not sure about the 6.0s and up?
It's under the dash near the steering column.
Attached Images
File Type: jpg 97 Baro sensor.JPG (53.1 KB, 12 views)
Highslide JS
__________________
Doug
86 F350 4x4 - Original owner
Was a 460 and will be a 00 SD 7.3, 550HP
Superlift 6", tilt front-end, dump bed, ARB lockers front and rear, 4 wheel discs, E40D

97 F350 PSD
E4OD, stock DD.
Reply With Quote
  #6  
Old 11-21-2012, 05:04 PM
Smokerblack's Avatar
Smokerblack Smokerblack is offline
Technical Specialist
 
Join Date: May 2011
Location: Pennsyltucky
Posts: 7,916
Default

Quote:
Originally Posted by JBone View Post
Here is some info for you.

Barometric Pressure Sensor
The Barometric Pressure (BARO) sensor is a variable capacitor sensor that processes a signal indicating atmospheric pressure. This allows the PCM to compensate for altitude. The PCM uses this information to calculate injection timing and glow plug control. With the 1999-1/2 model, the BARO sensor is no longer a stand alone component. It is now contained in the PCM.

A BARO sensor fault will result in an out-of-range signal to the PCM. The PCM will assume a default value of 100 kPa (14.5 psi) .
Quote:
Originally Posted by rosyruby View Post
The OBSs and SDs 7.3s have it, but not sure about the 6.0s and up?
It's under the dash near the steering column.
Yep and yep.... 6.0 use that sensor for fan speed clutch and Vgt control
__________________
~~~~~1997 F350 Cab-n-chassis, sureflows, 38R (1.0), T500, AD2, 910's, Southbend, autometer, AFE~~~~~
~~~~~E1999 F350 Puller BWD S480 FMW, HDP mount and fuel, BTS pumps, BTS trans, Comp, autometer, AFE~~~~~
Reply With Quote
  #7  
Old 11-21-2012, 06:05 PM
eaglehawk's Avatar
eaglehawk eaglehawk is offline
stroker envy
 
Join Date: May 2012
Location: Spokane, WA
Posts: 549
Default

Quote:
Originally Posted by JBone View Post
Here is some info for you.

Barometric Pressure Sensor
The Barometric Pressure (BARO) sensor is a variable capacitor sensor that processes a signal indicating atmospheric pressure. This allows the PCM to compensate for altitude. The PCM uses this information to calculate injection timing and glow plug control. With the 1999-1/2 model, the BARO sensor is no longer a stand alone component. It is now contained in the PCM.

A BARO sensor fault will result in an out-of-range signal to the PCM. The PCM will assume a default value of 100 kPa (14.5 psi) .
Thank you for the info, but unfortunately it is info I already know and did not answer the questions asked.

Beginning in '03 and on with the 6 liter the barometric sensor was moved inside the computer. However, up until then only a few models had them in the computer as a test basis for the 6 liter platform.

What I am trying to find out is if the 2000 model DAC3 had the bps in the ficm or if it was using a stand alone.

I am also trying to find the values in DC volts for what the bps should read at around 500 feet above sea level. Mine is reading -4.57 and remained the same when unplugged. If understanding is correct that then reads 4000 some feet below sea level.
__________________
Black E'99 F-350 CC DRW, 6637 filter, 4 inch straight piped. Soon to get an 99.5-03 model GTP 38r and intake, 160cc single shot injectors, T-500, regulated return, bellowed up-pipes, banks brake, frame mount 3rd battery 19.5" rims and tires with a little luck a rebuilt motor and trans, led everything. really thinking a ground up on it for a working show truck

"Safety Through Visibility"
Reply With Quote
  #8  
Old 11-21-2012, 06:08 PM
eaglehawk's Avatar
eaglehawk eaglehawk is offline
stroker envy
 
Join Date: May 2012
Location: Spokane, WA
Posts: 549
Talking

Quote:
Originally Posted by Andrew View Post
The pcm makes a calculation based off of the map and ebp sensors I do not believe the pcm on the diesels have a baro sensor what are you scaning with ?
Unfortunately the do have baro sensors. I was kind of hoping you knew since you were getting deeper into reprogramming them. I am not sure what system Mike has as I forgot to ask but if I recall it is the better one for monitoring system functions and relative data.
__________________
Black E'99 F-350 CC DRW, 6637 filter, 4 inch straight piped. Soon to get an 99.5-03 model GTP 38r and intake, 160cc single shot injectors, T-500, regulated return, bellowed up-pipes, banks brake, frame mount 3rd battery 19.5" rims and tires with a little luck a rebuilt motor and trans, led everything. really thinking a ground up on it for a working show truck

"Safety Through Visibility"
Reply With Quote
  #9  
Old 11-21-2012, 08:02 PM
eaglehawk's Avatar
eaglehawk eaglehawk is offline
stroker envy
 
Join Date: May 2012
Location: Spokane, WA
Posts: 549
Default

Take out the FICM of the picture, I am just trying to find answers to the two questions please

For the life of me I cannot understand why you don't understand (no offense, not my intention)

the PCM and the ficm are the same thing in function.

I need to know at what voltage should the bps be at at 500 feet above sea level, should it be in the negative or positive range of 12 volt dc

I need to know if the DAC3 model computer has a built in bps and if so how do I disable the stand alone bps that this truck originally came with.

I cannot be any more clear or explain it any better, please if you do not understand do not reply to this post. Thank you
__________________
Black E'99 F-350 CC DRW, 6637 filter, 4 inch straight piped. Soon to get an 99.5-03 model GTP 38r and intake, 160cc single shot injectors, T-500, regulated return, bellowed up-pipes, banks brake, frame mount 3rd battery 19.5" rims and tires with a little luck a rebuilt motor and trans, led everything. really thinking a ground up on it for a working show truck

"Safety Through Visibility"
Reply With Quote
  #10  
Old 11-21-2012, 08:50 PM
pjwoolw's Avatar
pjwoolw pjwoolw is offline
Moderator
 
Join Date: Feb 2009
Location: San Ramon Ca.
Posts: 3,525
Default

From what I've been able to gather the E99 rigs have the external BPS. Your PCM (DAC3 / DPC-421) shows to be only used in 1999 so that follows your model year. So I would think its safe to say you have an external to the PCM BPS. Also 4.6 volts at sea level is normal from what I've read.

Its location is to the passenger side of the steering column up behind the dash somewhere. Again I've never seen one in a SD rig but from what I understand that is the location.
__________________
Pete in San Ramon
2005 F250 6.0 Lariat 4x4 CC Short bed (stock)
1997 F250 7.3 XLT 4X4 Reg. cab AC injectors and pushrods from Farmer's Diesel and Performance, Terminator Engineering T500, Strictly / Driven Diesel top end / Beans pump and filters for EFS, DP-Tuner F6 chip, Diamond Eye 4" exhaust, S@B intake, stock rebuilt turbo / 1.0 housing / Banks wheel from Ron's Turbo, and allot of stuff from Riff Raff Diesel.
1986 F250 6.9 XLT Gone but not forgotten



And his hair was perfect. Ahhwooooo...
Reply With Quote
  #11  
Old 11-21-2012, 08:54 PM
dJohnSon's Avatar
dJohnSon dJohnSon is offline
5 speed Junkie
 
Join Date: Dec 2010
Location: Lake Tapps
Posts: 1,697
Default

My guess is the chip overrides the PCM and doesn't need the sensor. I know mine isn't hooked up but mine is an OBS so it could be different for superduties's but I couldnt see why.
__________________
1996 powerstroke 5spd shortbed, 3" downpipe, afe big boost, ts chip with Andrew's tunes, T500, 225/100 Sureflows, 475 South Bend Clutch, HFSB, 477hp
Reply With Quote
  #12  
Old 11-21-2012, 08:55 PM
eaglehawk's Avatar
eaglehawk eaglehawk is offline
stroker envy
 
Join Date: May 2012
Location: Spokane, WA
Posts: 549
Default

actually the DAC3 is out of a 2000, the AWA1 was the stock computer. and the bps was showing negative 4.53 not a positive number. Yes this truck is stock with an external bps. the key here is the values that we are reading and if the computer has an internal bps. Some of the computers in the later SD's had internal. while others had an external
__________________
Black E'99 F-350 CC DRW, 6637 filter, 4 inch straight piped. Soon to get an 99.5-03 model GTP 38r and intake, 160cc single shot injectors, T-500, regulated return, bellowed up-pipes, banks brake, frame mount 3rd battery 19.5" rims and tires with a little luck a rebuilt motor and trans, led everything. really thinking a ground up on it for a working show truck

"Safety Through Visibility"
Reply With Quote
  #13  
Old 11-21-2012, 09:04 PM
eaglehawk's Avatar
eaglehawk eaglehawk is offline
stroker envy
 
Join Date: May 2012
Location: Spokane, WA
Posts: 549
Default

Quote:
Originally Posted by dJohnSon View Post
My guess is the chip overrides the PCM and doesn't need the sensor. I know mine isn't hooked up but mine is an OBS so it could be different for superduties's but I couldnt see why.
Even if the computer is chipped the program is still based off the values that the computer generates. The OBS's computer did not control as many sensors so it had to do less. As ford engineered more sensors into the platform the computer had more to read and more to control becoming more complicated due to lengthy algorithms that had to be written to interpret the data that had to be collected for each combustion event.
__________________
Black E'99 F-350 CC DRW, 6637 filter, 4 inch straight piped. Soon to get an 99.5-03 model GTP 38r and intake, 160cc single shot injectors, T-500, regulated return, bellowed up-pipes, banks brake, frame mount 3rd battery 19.5" rims and tires with a little luck a rebuilt motor and trans, led everything. really thinking a ground up on it for a working show truck

"Safety Through Visibility"
Reply With Quote
  #14  
Old 11-21-2012, 09:12 PM
pjwoolw's Avatar
pjwoolw pjwoolw is offline
Moderator
 
Join Date: Feb 2009
Location: San Ramon Ca.
Posts: 3,525
Default

Oops. Got my DPC codes confused. As far as your voltage reading goes positive or negative I don't know for sure. But since you are somewhere close to sea level. I would think that if there was a malfunction it would throw a code. There are PIDS for BPS issues.
__________________
Pete in San Ramon
2005 F250 6.0 Lariat 4x4 CC Short bed (stock)
1997 F250 7.3 XLT 4X4 Reg. cab AC injectors and pushrods from Farmer's Diesel and Performance, Terminator Engineering T500, Strictly / Driven Diesel top end / Beans pump and filters for EFS, DP-Tuner F6 chip, Diamond Eye 4" exhaust, S@B intake, stock rebuilt turbo / 1.0 housing / Banks wheel from Ron's Turbo, and allot of stuff from Riff Raff Diesel.
1986 F250 6.9 XLT Gone but not forgotten



And his hair was perfect. Ahhwooooo...

Last edited by pjwoolw; 11-21-2012 at 09:30 PM.
Reply With Quote
  #15  
Old 11-21-2012, 09:40 PM
eaglehawk's Avatar
eaglehawk eaglehawk is offline
stroker envy
 
Join Date: May 2012
Location: Spokane, WA
Posts: 549
Default

That is the biggest problem we have ran into is technically if the DAC3 has an internal bps than it is contradicting the stand alone. Yet it won't give a code if the sensor goes bad, it merely gives a value to the computer to tell it how far above sea level, or below, and the computer then compensates fuel air ratio based on that data. Basically if you are at sea level where the air is heaviest,also temp related, the computer based on the value given by bps will defuel the ratio to compensate for the higher oxygen content available at sea level v.s. at high elevations the computer may add more fuel to compensate for less oxygen. I actually think I have that backwards. To tired to tell but hopefully it helps you understand it's function better and the role it plays in determining fuel to air ratios
__________________
Black E'99 F-350 CC DRW, 6637 filter, 4 inch straight piped. Soon to get an 99.5-03 model GTP 38r and intake, 160cc single shot injectors, T-500, regulated return, bellowed up-pipes, banks brake, frame mount 3rd battery 19.5" rims and tires with a little luck a rebuilt motor and trans, led everything. really thinking a ground up on it for a working show truck

"Safety Through Visibility"
Reply With Quote
  #16  
Old 11-21-2012, 10:58 PM
pjwoolw's Avatar
pjwoolw pjwoolw is offline
Moderator
 
Join Date: Feb 2009
Location: San Ramon Ca.
Posts: 3,525
Default

Looking at the E99 wiring diagrams I found Baro comes into the PCM on pin 63. Then looking at a another drawing of the PCM connector pin 63 isn't used. I'm assuming this was for later models. So it looks like with your 2000 PCM the external BPS is out of the equation.
__________________
Pete in San Ramon
2005 F250 6.0 Lariat 4x4 CC Short bed (stock)
1997 F250 7.3 XLT 4X4 Reg. cab AC injectors and pushrods from Farmer's Diesel and Performance, Terminator Engineering T500, Strictly / Driven Diesel top end / Beans pump and filters for EFS, DP-Tuner F6 chip, Diamond Eye 4" exhaust, S@B intake, stock rebuilt turbo / 1.0 housing / Banks wheel from Ron's Turbo, and allot of stuff from Riff Raff Diesel.
1986 F250 6.9 XLT Gone but not forgotten



And his hair was perfect. Ahhwooooo...
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 10:11 PM.


Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
FordDieselPower.com is not in any way associated with Ford Motor Company.
FordDieselPower.com is not in any way associated with Navistar International Corporation.
Ford and Powerstroke are copyrighted and trademarked to Ford Motor Company.
Materials are Copyright 2008 - 2014, FordDieselPower.com