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ECI checker reveals (barometric) pressure sensor out of spec ?? Solved


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#1 Jay40245

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Posted 09 May 2019 - 02:51 PM

89 Conquest, stock throttle body injection with stock mass air flow sensor.  
   ECI checker reads a value of 0 for the pressure sensor ( channel b2 on the checker) across the board. Correct voltage should read 2.1-2.5 volts with the ignition in the on position, and 0.2-1.2 volts at idle (at sea level).
   I've poured over the FSM and the sqc archives ad nauseam regarding any information on the barometric pressure sensor with no success. So I have a few questions for any takers:
  1) assuming that the harness is in good repair, does this reading imply that I need a new mass air flow sensor?
  2) could this out of spec reading cause a rich issue at wide open throttle?
  3) in order to trace the wiring for a potential break, or to back probe the connector itself, which wire in the harness leading to the mass airflow sensor connector is the wire for the pressure sensor?
   Thanks in advance for any guidance or insight.
Jay

Edited by Jay40245, 10 May 2019 - 06:15 PM.






#2 Ressurect1on

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Posted 09 May 2019 - 05:53 PM

are you checking voltage or reading a data output?  have you checked the 5 volt reference wire to the sensor?

#3 Jay40245

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Posted 09 May 2019 - 06:17 PM

View PostRessurect1on, on 09 May 2019 - 05:53 PM, said:

are you checking voltage or reading a data output?  have you checked the 5 volt reference wire to the sensor?
This is the voltage reading from the ECI checker (0 volts). the voltage numbers that I should see (as mentioned above) are directly from the ECI checker manual that came with the unit. I don't know if it's possible to isolate the barometric pressure sensor, and I don't even know what it looks like. Best I can gather from what little is mentioned about it, it is part of the mass air flow sensor assembly. I'm at a complete loss is to where exactly it is, and how to troubleshoot it. There is just no source material on this.

#4 Ressurect1on

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Posted 09 May 2019 - 07:52 PM

aaah True, i missed where you mentioned it is an 89 model year, i will look at the service manual and see what i can dig up when i get home after taking care of other things.

#5 scott87star

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Posted 10 May 2019 - 08:18 AM

86's are the only year that had a pressure sensor so for an 89 0 volts would be correct.
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#6 ucw458

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Posted 10 May 2019 - 09:08 AM

The Barometric pressure sensor is built into the mass air sensor.  It's listed in the fuel section of the FSM.  Section 14 page 63.
My 87
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#7 Jay40245

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Posted 10 May 2019 - 02:21 PM

@scott87star- on its face, that makes sense because wouldn't that sensor be for a speed density system? That's how my typhoon metered air. What's bizarre is there is actually a half a page dedicated to testing the pressure sensor in my 89 model year specific FSM (14-39).
http://imgur.com/gallery/S3OFxQC
@ucw458- based on the passage in the FSM (see link above), that's the impression I got. What's weird is on page 14-33 of the 89 model FSM, the chart for the different channels of the ECI checker are mentioned, but channel B2 (pressure sensor) is left blank.
http://imgur.com/gallery/5DrJAy0
  So to summarize, there is evidence in the FSM to support what you're saying (pressure sensor is integrated into the MAS) . Conversely, there is also verbiage in the FSM to support what Scott says (no pressure sensor on the vehicle).


#8 Jay40245

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Posted 10 May 2019 - 02:38 PM

Turns out you're both right. I didn't realize there was a difference between a pressure sensor and barometric pressure sensor. It took me trying to reconcile what I perceive to be contradicting statements to dig deep enough to get clarification from the manual. Thanks guys!

#9 Ressurect1on

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Posted 12 May 2019 - 04:03 PM

Glad you got it figured out. last week turned out to be a lot busier then i had desired.  so i never got around to it..

unfortunately other studies are also taking precedence ( need to get my CCENT and CCNA cert done with already been procrastinating it.)




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