Fox Xtremely high fuel consumption

I dunno about you but I get that kind of mileage because of my foot and an addiction to blower whine.

I also think I run a little rich at cruise.
Well with a blower it justifies the hit on fuel economy because of the demand but on a NA set up it is not justified specially when I tried different styles of driving, that is going easy on the throttle or being aggressive doesn’t make any difference too much fuel gone.

Thank you
 
SORRY, I HAVE TO ASK THIS QUESTION:
There is a sensor not too many people talk about and who knows maybe this is my problem!
I’ve read that a failing BAP sensor not always triggers the check engine and don’t always produce an error code in the ECU. One of the symptoms of a failing BAP sensor is a high fuel consumption.
Dos anyone in here had that sensor failing? And how do you test it without a frequency tester?
This BAP sensor communicates with the MAF sensor to do the appropriate air speed and density to adjust fuel/Air mixture. I hope this is the root of my issues but must have some expertise from all of you plus how to test it.

Thank you all so much!!! IMG_6593.webp
 
So are saying that if I unplug that thing will only affect me during startup and the MAF and computer will disregard the signal from this barometric pressure sensor? Now I’m more confused…

It references air pressure at startup so it knows which cold fuel table to go to.

Once you're warmed up and in closed loop, the HEGO and other sensors make that determination.
 
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It references air pressure at startup so it knows which cold fuel table to go to.

Once you're warmed up and in closed loop, the HEGO and other sensors make that determination.
Ok I got you,
Now one question just arises
Is that BAP sensor a specific part number per vehicle year?
My question is because I removed the BAP sensor from my 90 GT and the Part Number is E7EF-9F479-A2A
But when I did a google search AI suggested part number:

  • Ford OEM Number: E7FZ-12A644-A
  • Engineering Number: E7EF-12A644-A1A or
    A2A
  • LMR Part Number: LRS-12644A
Is there any difference if I use either one or this could be the root of the extremely high fuel consumption?

Thank you much for the help!
 
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This is what AI suggested when I asked
On a 90 mustang GT will a failing or wrong BAP sensor always cause an error code or will it induce an extremely poor fuel economy?

No, a failing or incorrect Barometric Pressure (BAP) sensor on a 1990 Mustang GT (5.0L) will not always trigger an error code (Check Engine Light), but it will frequently cause poor fuel economy, idle issues, or a rich running condition.
The 1990 Mustang GT uses a Mass Air Flow (MAF) system, where the BAP sensor communicates the ambient air density to the Electronic Control Assembly (ECA/ECU) to calculate fuel injection and spark timing.
LMR.com +2
Here is a breakdown of why it may not trigger a code and its impact on fuel economy:

1. Will a Failing/Wrong BAP Sensor Always Cause a Code?
  • No, not always: A BAP sensor can be "lazy," "drifting," or partially inaccurate, sending incorrect voltage readings that are still within the pre-programmed "range" of the computer. If the computer believes the voltage is plausible, it will not set a code.
  • "Wrong" Sensor Issue: Using a MAP sensor (intended for Speed Density) in place of a BAP sensor (for Mass Air), or vice-versa, can cause the car to run poorly or flood (rich condition) without necessarily showing a check engine light, because the computer is operating on false altitude/pressure data.
  • Common Codes (When they do appear):If the sensor fails completely, the computer may detect a voltage that is too high or too low, leading to Code 22 (BP sensor out of range).

2. Will it Always Cause Poor Fuel Economy?
  • High Probability: A failing BAP sensor often tricks the computer into thinking the car is at a higher altitude (lower air density). To compensate, the computer restricts fuel. However, more often, a faulty sensor causes the engine to default to an overly rich air-fuel ratio.
  • Symptoms: This results in excessive fuel consumption, black smoke from the exhaust, "lumpy" or erratic idle, and spark plugs fouling.
  • Performance Issues: A bad BAP sensor can cause the car to fall into a "limp mode," causing sluggish performance and hesitation.
    YouTube +4

3. Diagnosis and Context for 1990 Mustang GT
  • Location: The BAP sensor is located on the firewall, behind the engine, often near the passenger side, usually identified by a 3-pin connector and no vacuum line attached (unlike a MAP sensor).
  • Testing: If you suspect a problem, you must use a multimeter to check the voltage output to see if it corresponds to your current atmospheric pressure.
  • Other Causes: Because the BAP sensor is rarely the only cause of poor fuel economy, you should also inspect the Mass Air Flow (MAF) sensor, oxygen sensors, and check for vacuum leaks.
    LMR.com +4
Summary: The 1990 Ford ECU is not as sophisticated as modern OBD2 systems, making it highly possible to have a faulty BAP sensor that makes the car run very rich (poor MPG) without a Check Engine Light.

Will it make sense and by using the correct BAP sensor might help solving my poor fuel economy?????

Please comment, thank you
 
There are different part numbers however, I converted to MAF from SD and am still using the same MAP/BAP. The only difference for me is that the vacuum line had to removed so the sensor is in open air.
Ok but the two sensors with different part number send different frequency signal enough to require me to have the specific sensor for my 90 GT with manual transmission or it doesn’t matter? Do I have the wrong sensor?

Thank you
 
Well apparently those two BAP sensors are interchangeable so what else could be causing to affect my fuel economy?

I’ve done everything I know and all that was suggested and I see no improvements.

One thing that I still don’t have too clear is with regard to my injectors. How could it affect my MPG if I’m using 19lb? Are they maxed out and are over fueling?

I’m running out of options here
 
Well apparently those two BAP sensors are interchangeable so what else could be causing to affect my fuel economy?

I’ve done everything I know and all that was suggested and I see no improvements.

One thing that I still don’t have too clear is with regard to my injectors. How could it affect my MPG if I’m using 19lb? Are they maxed out and are over fueling?

I’m running out of options here
Your injectors aren't causing the poor MPG issue. Something else is causing it.

A wideband would be a great diagnostic tool.
 
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I know you said the speedo is calibrated correctly but is it possible that the odometer is having issues? Just wondering if it is not recording enough miles and you are actually driving more miles than the odometer is recording.