P0172/75 to P2196/98

[BigRed2004]

I have a 2004 EB 5.4 2WD with about 187K on the odometer. About 2 weeks ago (Dec. 18) I got a check engine light and when I ran the scan tool I got the codes P0172 and P0175. Generic codes stated that Banks 1 & 2 were running too rich. Ford Specific codes stated ‘Fuel System Too Rich Conditions’. I was able to finally get around to cleaning the MAF Sensor today (Dec. 31). Started the EB up with no problems, no codes, ran until engine got to temp and turned it off. About 20-30 minutes later I went out to run errands with the wife and the check engine light came on. Now I’m coding P2196 & P2198, ‘O2 Sensor Signal Stuck Rich’ for Bank 1 Sensor 1 and Bank 2 Sensor 1.

I’m not getting any other codes indicating a vacuum leak. There are no strange ticks, whistles, or other noises. The engine is not running rough, or worse. Idle has actually gotten better since cleaning off the MAF Sensor. The engine is not stalling or dying. I’ve cleared the new codes for them to come back in about 5 minutes or so.

I have to get smogged soon and register so this is concerning.

Could the new codes be from cleaning the MAF and the computer having to recalibrate?
Could running some Sea Foam Spray through the intake work?
Or is it likely I have to bite the ugly bullet of buying new O2 sensors?

Willing to answer any questions I can to help provide more input if needed to help diagnose the issue at hand.

 

[whtbronco]

I think it's very unlikely that the O2 sensors are faulty. Having both fail at the same time is rather unusual. With no other responses thus far I'll offer my thoughts.

There's got to be another common source, like fuel pressure. Here's what I found the DTC's you listed. I'd start my search with a quick intake search for air leaks and then look at the fuel pressure regulator, Ford appears to call it fuel pulse damper.

My experience has been that when the diaphragm in the fuel pressure regulator fails you'll get excess fuel into the intake via the vacuum hose connected to it. This could cause it to be rich all the time. Pull the vacuum hose off and see if there is fuel in it, it should be dry. I have also seen them fail with basically no fuel in the vacuum hose. I had to start a vehicle and then pull the vacuum hose off and plug it with a finger and see if any fuel spurts out of the vacuum port on the regulator.

The regulator is on the fuel rail. See drawing below with the numbers all pointing to the regulator and this link for pictures of it: https://www.rockauto.com/en/moreinfo.php?pk=1320621&cc=1427756&pt=6120&jsn=572

 

[BigRed2004]

@whtbronco thank you for the response for a potential solution. I have (2) more questions now as it relates to the information provided.

1. Where did you get the OBD code sheet? I have the workshop manuals, but I don’t have any documents explaining what the OBD codes are. So far my searches for a document have just lead me to websites that want to tell we the code is, but I would like something like a Ford manual.

2. Is it a fuel pressure dampener or is it a fuel pressure regulator? On the Rock Auto website for my vehicle it offers both as an option.


And when I look at the Ford Manual it states ’pressure regulator’ and shows this:

This matches this link from Rock Auto:

More Information for HOLSTEIN 2FPR0012

The dampener doesn’t have the smaller nipple sticking out. That appears to be the only difference.

 

[whtbronco]

Those ODBII code screen shots came from AllDataDIY. I pay for a subscription for all of my vehicles. I used to think it was expensive, now I think it's a bargain. The AllData info is based on the factory manuals.

Ford likes to call it a damper, I have always called it a regulator. AllData shows it as a fuel pulse damper. Either way it's the same thing. Though I see what you're saying since RockAuto appears to show 2 different types. I think the part you would need if failed is called the damper on RockAuto's site.

AllData listed part #: XL5Z9F775AA
XL5Z9F775AA was replaced with XL5Z9F775B according to Ford which matches the SMP labeled damper at RockAuto.

BTW, the damper/regulator is on the driver side fuel rail towards the back. Kind of just below and behind the EGR valve.

AllData instructions for replacing the damper/regulator:
FUEL PULSE DAMPER
REMOVAL
WARNING:

• • Do not smoke or carry lighted tobacco or open flame of any type when working on or near any fuel-related components. Highly flammable mixtures are always present and can be ignited. Failure to follow these instructions can result in personal injury.
• Fuel in the fuel system remains under high pressure even when the engine is not running. Before working on or disconnecting any of the fuel lines or fuel system components, the fuel system pressure must be relieved. Failure to follow these instructions can result in personal injury.

1. Relieve the fuel pressure.

1. Remove the fuel pulse damper.

1	Disconnect the vacuum hose.
2	Remove the snap ring.
3	Remove the fuel pulse damper.

1. Remove and discard the fuel pulse damper O-ring seals.

INSTALLATION

1. CAUTION: Use O-ring seals that are made of special fuel resistant material. Use of ordinary O-ring seals can cause the fuel system to leak. Do not reuse the O-ring seals.

NOTE: Lubricate the new O-ring seals with clean engine oil to aid installation.
To install, reverse the removal procedure.

 

[BigRed2004]

@whtbronco, thank you again for all your input. I was able to figure out what the problem was with the codes.

So I did have a vacuum problem after all, and it was nothing to do with the O2 sensors or Fuel Pulse Dampener. It was a vac line that went from the Vacuum Control Valve to the Intake Manifold. It was burned through and sealed off by the EGR Valve. The only thing I can think of was somehow in the past I didn’t put all the lines back in the right order, I put the engine cover back on about 3 weeks go, and it must have pushed the vac line into the EGR Valve. Part of the vac line had shaped itself to match the EGR Valve.






Finding this problem was very stressful as I have not been able to find a place to order a new vacuum harness. Fortunately I was able to find a usable harness at my local Pick-A-Part for less than $3.00 pre-tax. I picked up (2) of them To have a spare. I spent about (90) minutes taking the old broken harness off and putting the salvaged one in. The scariest part was removing the harness at the “T” joint. My old harness was showing signs of age and was crumbly in places. Thanks to silicone, picks, and patience, I was able to remove it. I found some shrink wrap to reenforce the old rubber and installed the harness.




After all that I got a P0122 code on the TPS sensor. My neighbor suggested disconnecting the battery for (20) minutes which seems to have helped. I’ve gone on several drives now with smoother start ups, smoother idles, and no more orange light or codes. I see zero problems with now registering.

Thank you, again.

 

[BigRed2004]

I also took off a Fuel Pressure Dampener/Regulator and saw that it was the ‘dampener’ with no nipple.



Which is odd, given the manual shows the ‘regulator’ with a nipple. At least now I know if I need this part in the future.

 

[whtbronco]

That's great news. Glad you got it figured out and resolved.

You can also buy some universal connectors and some vacuum hose in various sizes and piece the harness together should you need to in the future.

I took that dang cover off 3 times. The 3rd time it found it's way to the attic and has been there since 2004. It's pointless, has insanely long mounting bolts and can only cause issues. I call them ugly covers since engines are so dang ugly manufacturers found it necessary to cover them up. GM even call calls it a fuel injection sight shield so it seems they agree with my "ugly cover" assessment, haha.

 

[BigRed2004]

Thanks for the advice on piecing together a new harness if needed in the future. It was quicker right now to go to the yard and find one. But I will keep that in mind if any future issues arise.