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The issue is presuming that the aftermarket sensor is "updated". If it was "updated" the factory would be putting it in new vehicles which they are not.

There are some nonconsequential visual differences but no one has presented any evidence that there is anything about it that is functionally different or that it is more reliable.

I have been an engineer supporting manufacturing for over 40 years and every time you go to a different supplier for a part made to the exact same spec it is almost inevitable there will be visual differences. Considering the millions of this sensor Ford has put in all their gasoline engines for the past 10 years the only conclusion i can make is it is nothing more than a part from another supplier.

Dave
Actually mid 2018 Ford started putting the "new" sensor in the eco mustang, i can't speak for other 2.3 vehicles, but the mustang was definitely updated in 2018.

It's also not just a visual change.



The item ordered was BU5Z-9F972-B. However, the actual part number on the sensor is BU5A-9F972-CA. (New sensor on bottom). According to some posts, the 2018 Mustangs still have the old sensor.

It appears the part has been revised by Ford. The revised sensor has an additional hole for atmospheric pressure.
 

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Actually mid 2018 Ford started putting the "new" sensor in the eco mustang, i can't speak for other 2.3 vehicles, but the mustang was definitely updated in 2018.

It's also not just a visual change.



The item ordered was BU5Z-9F972-B. However, the actual part number on the sensor is BU5A-9F972-CA. (New sensor on bottom). According to some posts, the 2018 Mustangs still have the old sensor.

It appears the part has been revised by Ford. The revised sensor has an additional hole for atmospheric pressure.
Good enough for me! I retract my earlier statement. If your car is a 15-18 swap that puppy out.
 

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Actually mid 2018 Ford started putting the "new" sensor in the eco mustang, i can't speak for other 2.3 vehicles, but the mustang was definitely updated in 2018.

It's also not just a visual change.



The item ordered was BU5Z-9F972-B. However, the actual part number on the sensor is BU5A-9F972-CA. (New sensor on bottom). According to some posts, the 2018 Mustangs still have the old sensor.

It appears the part has been revised by Ford. The revised sensor has an additional hole for atmospheric pressure.
I've had that pressure sensor sitting in my drawer for like a year....because I'm a major proponent of "If it ain't broke..."(even though, in this case, 'broke' would be a MAJOR problem that you wanna avoid). That's the best side by side comparison and description that I've seen yet. I am now sticking that thing on as soon as possible.

Do you think this could possibly be related to an occasional dip in RPM's when I'm idling?
 

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I've had that pressure sensor sitting in my drawer for like a year....because I'm a major proponent of "If it ain't broke..."(even though, in this case, 'broke' would be a MAJOR problem that you wanna avoid). That's the best side by side comparison and description that I've seen yet. I am now sticking that thing on as soon as possible.

Do you think this could possibly be related to an occasional dip in RPM's when I'm idling?
I can't say for certain thats the cause, mine had a rough idle and the updated Evap hose fixed that issue.

I also never had an issue will FRP actual being less than FRP desired, but after already going ecoboom once, I looked at every possible thing that could cause an issue. Something as cheap and easy as this sensor I just did it for peace of mind.

I'm with you on the if it's not broke don't fix it, until I saw Tune+, PD and Stratified all talking about this sensor and how if it fails you'll be starving your engine of fuel, that was enough for me to swap it out.

More info on the sensor:

  • The new lowside fuel pressure sensor cures a High Pressure Fuel problem. When the lowside fuel pressure sensor fails, when you get into load the fuel rail pressure will drop to almost 0. The high pressure fuel pump thinks there is a problem and instead of bypassing it just simply shuts down.
  • The EVAP purge solenoid update cures issues with the short term fuel trims when under load. When the EVAP purge solenoid fails the short term fuel trims will go to 0 and you will not get any fuel corrections under load (mostly full throttle) and the car can potentially go lean. If you have port injection or methanol injection, or making 400whp+ this can cause catastrophic failure.
  • Both items can fail without any check engine light, and you would have no way of knowing. It is best to just replace both of them to avoid any issues, they are extremely cheap.
 

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I've had that pressure sensor sitting in my drawer for like a year....because I'm a major proponent of "If it ain't broke..."(even though, in this case, 'broke' would be a MAJOR problem that you wanna avoid). That's the best side by side comparison and description that I've seen yet. I am now sticking that thing on as soon as possible.

Do you think this could possibly be related to an occasional dip in RPM's when I'm idling?
Not sure why you’re referring to the sensor as aftermarket. It is an OEM replacement that can be purchased directly from Ford.
Motorcraft is an aftermarket supplier of parts for Ford and other brands of vehicles. There are many many parts that Motorcraft sells for Ford as OE replacement that are not the same ones that come from the factory. Motorcraft is a separate profit and loss center within Ford so they have their own supplier base.

I call it aftermarket because it is not the same as the one that comes from the factory.

Dave
 

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I hope you guys that are replacing the sensor for good measure realize that a new unproven part is statistically more likely to fail than a part that has been performing correctly for a period of time.
.

The replacement sensor is neither new nor unproven, it has been in production and installed on new Ford vehicles since at least 2018 and so far hasn’t presented any indication of being problematic

In the case of the fuel pressure sensor Ford has been using the same part with the same part number in all gasoline engines since 2010 and still are. The after market part everyone is swapping in has some inconsequential minor visual differences but there is no evidence that it is any more reliable than the factory part (and it could have a higher failure rate).

Dave
Completely inaccurate, refer to Turbotigger’s post above.

The issue is presuming that the aftermarket sensor is "updated". If it was "updated" the factory would be putting it in new vehicles which they are not.
Also untrue, as Turbotigger posted above, the upgraded sensor has been installed in new vehicles since at least mid-2018.

With all due respect, you have many educational and informative posts, which I’m greatful for, as I’m sure many others are as well. Posting unfounded claims like this as fact detracts from the many great contributions you make.



I have been an engineer supporting manufacturing for over 40 years and every time you go to a different supplier for a part made to the exact same spec it is almost inevitable there will be visual differences. Considering the millions of this sensor Ford has put in all their gasoline engines for the past 10 years the only conclusion i can make is it is nothing more than a part from another supplier.
40 years as an engineer and that’s the “only” conclusion you can make, lol? Would a possible conclusion not be that maybe Ford recognized a weakness in the existing sensor and in response, designed a sensor less prone to failure?
Is it fair to assume you were a project engineer and not a process or production engineer?

I call it aftermarket because it is not the same as the one that comes from the factory.

Dave
I call it OEM because it is the exact same as the one that comes from the factory since 2018.

AFAIK, BU5Z-9F972-CA is the only one currently in production, as the old style (BU5Z-9F972-B) was phased out.

Also, Motorcraft offers genuine FoMoCo replacement parts, is owned, endorsed, and trademarked by Ford, built to Ford specifications, and can be picked up at any Ford dealership as a direct replacement. In many cases, their parts are built on the same assembly line alongside FoMoCo replacement parts, a far cry from what most consider as aftermarket.
 

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Possibly, I bought mine directly from my local ford dealership for $23 plus tax.
My 2018 came with the old style, and did fail. I already had the new one on hand as insurance, just never replaced it thinking if it ant broke don’t fix. Replaced it and the car ran like nothing ever happened. The new part does look slightly different than the old. Even if it was a case of different suppliers, not design differences, even when building to the same spec you get a slightly different product due to differences in raw materials, machining, manufacturing processes, and build quality. I run into this all the time in electronics manufacturing. Components are sourced from multiple suppliers, usually whoever has inventory, good price, and can deliver in time. Most times you don’t know a component is subpar until it fails a functional test, or worse fails in the field. In the case of this fuel sensor having experienced first hand a failure, I am a believer in replacing with the newer part.
 

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eBay a reliable source for these? Everywhere else is about twice the cost, wondering if there’s good reason for it
I got mine from ebay. Didn't cost much, delivered fast, works fine.
 

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I got mine from ebay. Didn't cost much, delivered fast, works fine.
I'm being cheeky, but the same can be said for the original version on my car, as delivered from the factory. I think the takeaway from this discussion is first, that if you are driving a stock vehicle and have concerns (whether real or perceived), go ahead and replace the sensor. I don't feel that it's necessary myself because: (a) the failure rate is anecdotal as the population of this forum and others represents only a fraction of the total S550 production; and (b) my car has not exhibited any indication of failure (and I run the dash with the A/F gauge up all the time to monitor). Second, if you are driving a tuned/modded car, you may want to consider changing it for peace of mind, as under such additional stress a failure could result in a catastrophic failure.
 

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.

The replacement sensor is neither new nor unproven, it has been in production and installed on new Ford vehicles since at least 2018 and so far hasn’t presented any indication of being problematic


Completely inaccurate, refer to Turbotigger’s post above.


Also untrue, as Turbotigger posted above, the upgraded sensor has been installed in new vehicles since at least mid-2018.

With all due respect, you have many educational and informative posts, which I’m greatful for, as I’m sure many others are as well. Posting unfounded claims like this as fact detracts from the many great contributions you make.





40 years as an engineer and that’s the “only” conclusion you can make, lol? Would a possible conclusion not be that maybe Ford recognized a weakness in the existing sensor and in response, designed a sensor less prone to failure?
Is it fair to assume you were a project engineer and not a process or production engineer?



I call it OEM because it is the exact same as the one that comes from the factory since 2018.

AFAIK, BU5Z-9F972-CA is the only one currently in production, as the old style (BU5Z-9F972-B) was phased out.

Also, Motorcraft offers genuine FoMoCo replacement parts, is owned, endorsed, and trademarked by Ford, built to Ford specifications, and can be picked up at any Ford dealership as a direct replacement. In many cases, their parts are built on the same assembly line alongside FoMoCo replacement parts, a far cry from what most consider as aftermarket.
Many Ford dealers will give you a portal into the parts system the parts department uses on their web page. I checked my local dealers system yesterday and it listed BU5Z-9F972-B as the low pressure fuel sensor for 2015 - 2019 Ecoboost Mustangs. Even the pictures folks have posted of the sensor and packaging has BU5Z-9F972-B on the packaging while the part had the -CA number on it. So i am not sure how any one would know if a particular version had been superceded. The portal actually said BU5Z-9F972-B superceded BU5Z-9F972-A which tells me they will change the part number in their parts system if they are superceding a part which is not the case.

Plenty of folks even in this thread have reported there 2018s have the -BA part. It would be interesting if folks with 2019s would pull off the connector on their cars and see how the parts is marked and report back.

Having worked in both the automotive and defense industries i know for a fact that both are very particular about part marking and they require that an identifier be on the part that links back to who actually made it. I certainly don't what Fords part numbering system is but when you have two parts that are marked with a variation of the listed part number that also have non consequential visual differences it leads me to the conclusion that it is the same part made by different suppliers.

The reason i do not believe that a design change occured between the -BA and -CA part is the technology used in sensors like this of a class called Microelectromechanical systems or MEMS. Since this sensor only has three connections, power, ground and output it would be a piezoresistive strain gauge chip that actually converts fuel pressure to an output voltage.

These MEMS start with a silicon wafer just like any IC. Then a cavity is etched on the back side leaving a thin diaphragm, the thickness will determine the pressure range. On the opposite side four resistor elements are doped into the silicon and are connected as wheatstone bridge. When pressure is applied the silicon deflects causing two resistors to go into compression reducing their resistance and two into tension increasing the resistance. This causes an imbalance giving you an output voltage proportional to pressure.

Like any IC the reliability is extremely high for a MEMS. There is also very little that can be done in the way of design changes that would not also require programing changes to the ECU. Mechanical changes to the housing are not going to effect the way the MEMS works.

The fact that this sensor has been in use since 2010 across all gasoline engines and there has been no recalls or TSBs and the same part number is still being called out in 2019 i have a hard time accepting that the - CA part is anything more than a different supplier. Even if it proves that the -CA part is now showing up from the factory in new cars i would be more inclined to believe it to be a supplier change because of cost or delivery advantages.

With all due respect to you and TurboTigger neither of you have presented any evidence that would refute my position. Its quite possible that i am all wet but until someone cuts both versions open and presents some compelling evidence to the contrary. If i am proven wrong i will be the first to admit it.

Not sure why you would presume i was a project engineer. I have worked for Lockheed Martin for the past 13 years, i am the lead manufacturing engineer in the Production Engineering department. My responsibilities include; guiding less experienced engineers in the group, designing manufacturing process, generating test plans, defining inspection requirements, designing tooling/fixturing, writing build procedures, providing day to day support of production lines and solving manufacturing & supplier issues. As a member of new product core teams i review design documents to ensure the designs are manufacturable and define design changes if they are not. I generate contract deliverable documents, interface with the customer on manufacturing topics and travel to customer sites to resolve product issues or assist in qualifications testing. I am also the site subject matter expert on environmental qualification testing and production environmental stress screening.


Dave
 

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Question for you Dave, you seem to know what you're talking about, so I trust your answers.
Would that tiny hole shown on what people say is the "NEW" part have any effect on the wafers deflection or response time as compared to the 'sealed' part, or would that portion of the electronics be separated from atmospheric venting? Does that hole represent a possible design update or might it just be a location jig for assembly orientation?
 

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Until some one opens one up we will not truely know. As you say it could be a tooling hole or a hole to inject potting compound to environmentally seal/protect the sensor chip & wiring or be an atmospheric reference hole. Back in the 80s we were one of the first companies to introduce a pressure transmitter for process control applications (think refineries and power plants) and to keep the chip isolated from the process there was a tin stainless steel diaphragm inbetween the process and the chip. This required the space be filled with fluid to transfer the fluid, it could be a fill port for that.

The problem with it being an atmospheric port it is in the worst possible place. Over time it will get plugged with crud. If it was necessary i would vent through the connector.

Keep in mind that from extreme low barometric pressure and extreme high represents about 3.5 psi and from sea level to 6000ft altitude represents about 10 psi. These extremes likely are not important to keeping adequate fuel at the high pressure pump.

Dave
 

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Dave, Boeing needs you!
 
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