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Fault Codes P2197 AND P2198 together

Old 01-13-2019, 11:37 AM
JHedrick is offline
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STFT, rather than Net FT (which I see as ST + LT). I see a "-" STFT, as in -29.03 (my actual %) and LTFT of 0.00, as the O2 sensor has read a very rich condition and commanded the removal of fuel and a "+" STFT, as in 53.00 (my actual %) and LTFT also at 0.00, as the sensor reading a lean condition and has commanded additional fuel. Once it gets through whatever is causing those readings, both return to normal ranges (STFT +/- 7 and LTFT -/+ 7 Less than 10, anyhow, and a net close to 0) The codes I am getting are P2197 and 98 which still relate to a stuck lean/rich O2 reading, but I am not sure if it relates to an intake problem as the P0171 and 74 DTC's seem to. THAT is part of my confusion. Do those numbers cross reference or do they relate to different systems? You Tube vids really only mention intake leaks and the "common" Ford lean issue as DTC's P0171 and 74.

As always, thank you for your time and consideration! It is GREATLY appreciated.

So here is a more complete history and my thoughts:

Vacuum leaks on B2: No apparent leaks during smoke test. I am considering using propane and listening to idle/watching live STFT data. I pulled top of intake off, down to the throttle body, looking for the elbow on the back of the intake. I could not locate it. Do I need to remove the intake manifold to get to it?? The exploded view of the manifold assembly Part#: 9424 shows no elbow, either. There is a part, 9G730, on the back of the manifold, but it is not an elbow, and appears to be IMRC related. I am not sure how to check the operation of the Vapor Solenoid as you suggested. I have pulled it (tapped it on the ground and blown into it LOL) and it shows no apparent damage, nor did I get smoke out of that end. I only waited about 20 minutes though, and Ford says their smoke test takes 4 hours.

Exhaust leak ahead of sensor: Truck is clean and in very good shape, no rust or damage other than wear and tear of raising 3 boys in athletics. Manifold nuts are clean and tight and I smell no exhaust under the truck.

Leaking/sticking injector: My buddy did an injector test and saw nothing to indicate this. I do understand that could be in the "unable to duplicate" category, and could still be the issue. I have replaced all of the coils within the last 5k miles. I was having that hesitation that is usually, mistakenly thought to be a transmission issue. Just a bad coil causing a "buck" at light acceleration, but NOT throwing a misfire DTC. Replaced the spark plugs at 80k (THAT was an experience, 3 broke). So I am inclined to believe it is not related to coils or plugs, either. At that time, I had had a coolant leak that sprayed onto one of the coils below causing that to fail, leading to a B1 loaded up, Cat. My Ford guy was kind enough to get the Cat covered for me.

Combustion leak: Truck has been serviced at regular intervals with synthetic, so I hope this is not the case. Other than the cyclical STFT issues, truck runs fine, and is making no unusual noises under the hood (like a valve issue). I have gotten no misfire DTC's either, but, as Richard has commented, apparently Fords don't throw misfire codes easily.

My buddy is bringing his scanner today. We'll take a ride and see what his injector test shows under driving conditions. I may just have to bite the bullet and let Ford at least diagnose it. Hopefully, it's is something simple, that has escaped me. Thanks again, Richard and Jim.
Old 01-13-2019, 01:59 PM
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Originally Posted by JHedrick View Post
As a further issue, I got another pending P2198 (B2S1 rich) code this morning after driving about 10 highway miles, then returning to idle at an exit stoplight. Started idling rough, got code, then it smoothed out after a moment while sitting there, and the fuel trims on both banks returned to normal. I happened to be watching real time data on the fuel trim and watched the STFT reduce to -29% which explains the code, just not why..
Well, it doesn’t explain the “code” to me. The P2198 DTC is saying that the O2 sensor is “stuck” in the rich reading after the PCM forced an O2 sensor test. 10 miles later when sitting at the stop light observing real time data you are not observing the situation that caused the P2198. The negative 29% shows that the PCM is reducing fuel and eventually smoothed out the rough idle.
You might be better off viewing real time data for fuel pressure and MAP sensor readings. My question would be what could cause the condiction that requires so much fuel to be withdrawn?

When your buddy did the cylinder balance test, was it done by shutting off each fuel injector in turn, or shutting off each coil in turn? And what was the variance in cylinder power?
Old 01-13-2019, 04:55 PM
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As I was watching the STFT while driving, it went from normal, to 53 in B2, to normal in both banks, then to -29 in B2, once I hit the stop light and idles for a bit. Is that not "realtime"? Maybe I still do not understand how to interpret a scanner? I have just now gotten to the point where I kind of get FT and how it relates to certain codes. My buddy only did the test in the parking lot of his shop. No load, just idle, and 2000 rpm with overlaid graphs showing each cylinder. He said it was a rough test to see if anything obvious was happening. As with most of us with family/buddies in the business, we are subject to their availability, and I cannot wait much longer. He got tied up today, and could not come over. I have already spent $200 on a higher end (than entry-level) scanner, and his is a professional model. His own Dad (my neighbor) is waiting for him to have time to look at his truck, so I can't really push it. This Exp is what my wife drives... She just wants it fixed. SOMETHING is causing major fluctuations in air:fuel in B2. As usual, in my life, there are multiple things that could be causing it, and none of them have obviously presented themselves, but the problem is getting worse. The last thing I want is another Cat issue (or worse) that my guy can't cover this time. I feel like it's a betrayal to you guys and your time, by taking it to the Dealer, but I simply do not have the time or know-how to do much more myself, or the time to wait for my buddies to have the time. Thank you for your insight and knowledge. I always try to fix these things myself, but more often than not, find myself in this position. Just what I've come to expect. No worries. Thank you for your time!!
Old 01-14-2019, 12:42 PM
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Don't worry about me spending time to help. I am retired and always learn more about fixing my own car here on the forum. You need to get your car fixed soon. Let us know what it took to make it run right.

My grandson's Ford Fiesta had a lean condition and the fuel trims indicated a vacuum leak. He let it go way too long and had to replace the catalytic converter. His vacuum leak was after the mass air flow sensor. The clamp holding the big plastic air intake tube to the engine wasn't tight enough. Also the vacuum hose from the power brake system was loose. His fuel trim readings were steady - not like yours.

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